#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

"""
Worker that receives input from Piped RDD.
"""
import itertools
import os
import sys
import dataclasses
import time
import inspect
import itertools
import json
from typing import Any, Callable, Iterable, Iterator, Optional, Tuple

from pyspark.accumulators import (
    SpecialAccumulatorIds,
    _accumulatorRegistry,
    _deserialize_accumulator,
)
from pyspark.sql.streaming.stateful_processor_api_client import StatefulProcessorApiClient
from pyspark.sql.streaming.stateful_processor_util import TransformWithStateInPandasFuncMode
from pyspark.taskcontext import BarrierTaskContext, TaskContext
from pyspark.resource import ResourceInformation
from pyspark.util import PythonEvalType, local_connect_and_auth
from pyspark.serializers import (
    write_int,
    read_long,
    read_bool,
    write_long,
    read_int,
    SpecialLengths,
    CPickleSerializer,
    BatchedSerializer,
)
from pyspark.sql.conversion import LocalDataToArrowConversion, ArrowTableToRowsConversion
from pyspark.sql.functions import SkipRestOfInputTableException
from pyspark.sql.pandas.serializers import (
    ArrowStreamPandasUDFSerializer,
    ArrowStreamPandasUDTFSerializer,
    GroupPandasUDFSerializer,
    GroupArrowUDFSerializer,
    CogroupArrowUDFSerializer,
    CogroupPandasUDFSerializer,
    ArrowStreamUDFSerializer,
    ApplyInPandasWithStateSerializer,
    GroupPandasIterUDFSerializer,
    GroupPandasUDFSerializer,
    TransformWithStateInPandasSerializer,
    TransformWithStateInPandasInitStateSerializer,
    TransformWithStateInPySparkRowSerializer,
    TransformWithStateInPySparkRowInitStateSerializer,
    ArrowStreamArrowUDFSerializer,
    ArrowStreamAggArrowUDFSerializer,
    ArrowBatchUDFSerializer,
    ArrowStreamUDTFSerializer,
    ArrowStreamArrowUDTFSerializer,
)
from pyspark.sql.pandas.types import to_arrow_type
from pyspark.sql.types import (
    ArrayType,
    BinaryType,
    DataType,
    MapType,
    Row,
    StringType,
    StructType,
    _create_row,
    _parse_datatype_json_string,
)
from pyspark.util import (
    fail_on_stopiteration,
    handle_worker_exception,
    with_faulthandler,
    start_faulthandler_periodic_traceback,
)
from pyspark import shuffle
from pyspark.errors import PySparkRuntimeError, PySparkTypeError, PySparkValueError
from pyspark.worker_util import (
    check_python_version,
    read_command,
    pickleSer,
    send_accumulator_updates,
    setup_broadcasts,
    setup_memory_limits,
    setup_spark_files,
    utf8_deserializer,
)
from pyspark.logger.worker_io import capture_outputs

try:
    import memory_profiler  # noqa: F401

    has_memory_profiler = True
except Exception:
    has_memory_profiler = False


def report_times(outfile, boot, init, finish):
    write_int(SpecialLengths.TIMING_DATA, outfile)
    write_long(int(1000 * boot), outfile)
    write_long(int(1000 * init), outfile)
    write_long(int(1000 * finish), outfile)


def chain(f, g):
    """chain two functions together"""
    return lambda *a: g(f(*a))


def wrap_udf(f, args_offsets, kwargs_offsets, return_type):
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    if return_type.needConversion():
        toInternal = return_type.toInternal
        return args_kwargs_offsets, lambda *a: toInternal(func(*a))
    else:
        return args_kwargs_offsets, lambda *a: func(*a)


def wrap_scalar_pandas_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def verify_result_type(result):
        if not hasattr(result, "__len__"):
            pd_type = "pandas.DataFrame" if type(return_type) == StructType else "pandas.Series"
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": pd_type,
                    "actual": type(result).__name__,
                },
            )
        return result

    def verify_result_length(result, length):
        if len(result) != length:
            raise PySparkRuntimeError(
                errorClass="SCHEMA_MISMATCH_FOR_PANDAS_UDF",
                messageParameters={
                    "udf_type": "pandas_udf",
                    "expected": str(length),
                    "actual": str(len(result)),
                },
            )
        return result

    return (
        args_kwargs_offsets,
        lambda *a: (
            verify_result_length(verify_result_type(func(*a)), len(a[0])),
            arrow_return_type,
        ),
    )


def wrap_scalar_arrow_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def verify_result_type(result):
        if not hasattr(result, "__len__"):
            pd_type = "pyarrow.Array"
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": pd_type,
                    "actual": type(result).__name__,
                },
            )
        return result

    def verify_result_length(result, length):
        if len(result) != length:
            raise PySparkRuntimeError(
                errorClass="SCHEMA_MISMATCH_FOR_PANDAS_UDF",
                messageParameters={
                    "udf_type": "arrow_udf",
                    "expected": str(length),
                    "actual": str(len(result)),
                },
            )
        return result

    return (
        args_kwargs_offsets,
        lambda *a: (
            verify_result_length(verify_result_type(func(*a)), len(a[0])),
            arrow_return_type,
        ),
    )


def wrap_arrow_batch_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    if use_legacy_pandas_udf_conversion(runner_conf):
        return wrap_arrow_batch_udf_legacy(
            f, args_offsets, kwargs_offsets, return_type, runner_conf
        )
    else:
        return wrap_arrow_batch_udf_arrow(f, args_offsets, kwargs_offsets, return_type, runner_conf)


def wrap_arrow_batch_udf_arrow(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    from pyspark.sql.pandas.types import to_arrow_type

    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    zero_arg_exec = False
    if len(args_kwargs_offsets) == 0:
        args_kwargs_offsets = (0,)
        zero_arg_exec = True

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    if zero_arg_exec:

        def get_args(*args: list):
            return [() for _ in args[0]]

    else:

        def get_args(*args: list):
            return zip(*args)

    if "spark.sql.execution.pythonUDF.arrow.concurrency.level" in runner_conf:
        from concurrent.futures import ThreadPoolExecutor

        c = int(runner_conf["spark.sql.execution.pythonUDF.arrow.concurrency.level"])

        @fail_on_stopiteration
        def evaluate(*args):
            with ThreadPoolExecutor(max_workers=c) as pool:
                """
                Takes list of Python objects and returns tuple of
                (results, arrow_return_type, return_type).
                """
                return list(pool.map(lambda row: func(*row), get_args(*args)))

    else:

        @fail_on_stopiteration
        def evaluate(*args):
            """
            Takes list of Python objects and returns tuple of
            (results, arrow_return_type, return_type).
            """
            return [func(*row) for row in get_args(*args)]

    def verify_result_length(result, length):
        if len(result) != length:
            raise PySparkRuntimeError(
                errorClass="SCHEMA_MISMATCH_FOR_ARROW_PYTHON_UDF",
                messageParameters={
                    "udf_type": "arrow_batch_udf",
                    "expected": str(length),
                    "actual": str(len(result)),
                },
            )
        return result

    return (
        args_kwargs_offsets,
        lambda *a: (verify_result_length(evaluate(*a), len(a[0])), arrow_return_type, return_type),
    )


def wrap_arrow_batch_udf_legacy(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    import pandas as pd

    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)
    zero_arg_exec = False
    if len(args_kwargs_offsets) == 0:
        args_kwargs_offsets = (0,)  # Series([pyspark._NoValue, ...]) is used for 0-arg execution.
        zero_arg_exec = True

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    # "result_func" ensures the result of a Python UDF to be consistent with/without Arrow
    # optimization.
    # Otherwise, an Arrow-optimized Python UDF raises "pyarrow.lib.ArrowTypeError: Expected a
    # string or bytes dtype, got ..." whereas a non-Arrow-optimized Python UDF returns
    # successfully.
    result_func = lambda pdf: pdf  # noqa: E731
    if type(return_type) == StringType:
        result_func = lambda r: str(r) if r is not None else r  # noqa: E731
    elif type(return_type) == BinaryType:
        result_func = lambda r: bytes(r) if r is not None else r  # noqa: E731

    if zero_arg_exec:

        def get_args(*args: pd.Series):
            return [() for _ in args[0]]

    else:

        def get_args(*args: pd.Series):
            return zip(*args)

    if "spark.sql.execution.pythonUDF.arrow.concurrency.level" in runner_conf:
        from concurrent.futures import ThreadPoolExecutor

        c = int(runner_conf["spark.sql.execution.pythonUDF.arrow.concurrency.level"])

        @fail_on_stopiteration
        def evaluate(*args: pd.Series) -> pd.Series:
            with ThreadPoolExecutor(max_workers=c) as pool:
                return pd.Series(
                    list(pool.map(lambda row: result_func(func(*row)), get_args(*args)))
                )

    else:

        @fail_on_stopiteration
        def evaluate(*args: pd.Series) -> pd.Series:
            return pd.Series([result_func(func(*row)) for row in get_args(*args)])

    def verify_result_length(result, length):
        if len(result) != length:
            raise PySparkRuntimeError(
                errorClass="SCHEMA_MISMATCH_FOR_PANDAS_UDF",
                messageParameters={
                    "udf_type": "arrow_batch_udf",
                    "expected": str(length),
                    "actual": str(len(result)),
                },
            )
        return result

    return (
        args_kwargs_offsets,
        lambda *a: (verify_result_length(evaluate(*a), len(a[0])), arrow_return_type, return_type),
    )


def wrap_pandas_batch_iter_udf(f, return_type, runner_conf):
    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )
    iter_type_label = "pandas.DataFrame" if type(return_type) == StructType else "pandas.Series"

    def verify_result(result):
        if not isinstance(result, Iterator) and not hasattr(result, "__iter__"):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "iterator of {}".format(iter_type_label),
                    "actual": type(result).__name__,
                },
            )
        return result

    def verify_element(elem):
        import pandas as pd

        if not isinstance(elem, pd.DataFrame if type(return_type) == StructType else pd.Series):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "iterator of {}".format(iter_type_label),
                    "actual": "iterator of {}".format(type(elem).__name__),
                },
            )

        verify_pandas_result(
            elem, return_type, assign_cols_by_name=True, truncate_return_schema=True
        )

        return elem

    return lambda *iterator: map(
        lambda res: (res, arrow_return_type), map(verify_element, verify_result(f(*iterator)))
    )


def verify_pandas_result(result, return_type, assign_cols_by_name, truncate_return_schema):
    import pandas as pd

    if type(return_type) == StructType:
        if not isinstance(result, pd.DataFrame):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "pandas.DataFrame",
                    "actual": type(result).__name__,
                },
            )

        # check the schema of the result only if it is not empty or has columns
        if not result.empty or len(result.columns) != 0:
            # if any column name of the result is a string
            # the column names of the result have to match the return type
            #   see create_array in pyspark.sql.pandas.serializers.ArrowStreamPandasSerializer
            field_names = set([field.name for field in return_type.fields])
            # only the first len(field_names) result columns are considered
            # when truncating the return schema
            result_columns = (
                result.columns[: len(field_names)] if truncate_return_schema else result.columns
            )
            column_names = set(result_columns)
            if (
                assign_cols_by_name
                and any(isinstance(name, str) for name in result.columns)
                and column_names != field_names
            ):
                missing = sorted(list(field_names.difference(column_names)))
                missing = f" Missing: {', '.join(missing)}." if missing else ""

                extra = sorted(list(column_names.difference(field_names)))
                extra = f" Unexpected: {', '.join(extra)}." if extra else ""

                raise PySparkRuntimeError(
                    errorClass="RESULT_COLUMNS_MISMATCH_FOR_PANDAS_UDF",
                    messageParameters={
                        "missing": missing,
                        "extra": extra,
                    },
                )
            # otherwise the number of columns of result have to match the return type
            elif len(result_columns) != len(return_type):
                raise PySparkRuntimeError(
                    errorClass="RESULT_LENGTH_MISMATCH_FOR_PANDAS_UDF",
                    messageParameters={
                        "expected": str(len(return_type)),
                        "actual": str(len(result.columns)),
                    },
                )
    else:
        if not isinstance(result, pd.Series):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={"expected": "pandas.Series", "actual": type(result).__name__},
            )


def wrap_arrow_array_iter_udf(f, return_type, runner_conf):
    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def verify_result(result):
        if not isinstance(result, Iterator) and not hasattr(result, "__iter__"):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "iterator of pyarrow.Array",
                    "actual": type(result).__name__,
                },
            )
        return result

    def verify_element(elem):
        import pyarrow as pa

        if not isinstance(elem, pa.Array):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "iterator of pyarrow.Array",
                    "actual": "iterator of {}".format(type(elem).__name__),
                },
            )

        return elem

    return lambda *iterator: map(
        lambda res: (res, arrow_return_type), map(verify_element, verify_result(f(*iterator)))
    )


def wrap_arrow_batch_iter_udf(f, return_type, runner_conf):
    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def verify_result(result):
        if not isinstance(result, Iterator) and not hasattr(result, "__iter__"):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "iterator of pyarrow.RecordBatch",
                    "actual": type(result).__name__,
                },
            )
        return result

    def verify_element(elem):
        import pyarrow as pa

        if not isinstance(elem, pa.RecordBatch):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "iterator of pyarrow.RecordBatch",
                    "actual": "iterator of {}".format(type(elem).__name__),
                },
            )

        return elem

    return lambda *iterator: map(
        lambda res: (res, arrow_return_type), map(verify_element, verify_result(f(*iterator)))
    )


def wrap_cogrouped_map_arrow_udf(f, return_type, argspec, runner_conf):
    _assign_cols_by_name = assign_cols_by_name(runner_conf)

    if _assign_cols_by_name:
        expected_cols_and_types = {
            col.name: to_arrow_type(col.dataType) for col in return_type.fields
        }
    else:
        expected_cols_and_types = [
            (col.name, to_arrow_type(col.dataType)) for col in return_type.fields
        ]

    def wrapped(left_key_table, left_value_table, right_key_table, right_value_table):
        if len(argspec.args) == 2:
            result = f(left_value_table, right_value_table)
        elif len(argspec.args) == 3:
            key_table = left_key_table if left_key_table.num_rows > 0 else right_key_table
            key = tuple(c[0] for c in key_table.columns)
            result = f(key, left_value_table, right_value_table)

        verify_arrow_table(result, _assign_cols_by_name, expected_cols_and_types)

        return result.to_batches()

    return lambda kl, vl, kr, vr: (wrapped(kl, vl, kr, vr), to_arrow_type(return_type))


def wrap_cogrouped_map_pandas_udf(f, return_type, argspec, runner_conf):
    _use_large_var_types = use_large_var_types(runner_conf)
    _assign_cols_by_name = assign_cols_by_name(runner_conf)

    def wrapped(left_key_series, left_value_series, right_key_series, right_value_series):
        import pandas as pd

        left_df = pd.concat(left_value_series, axis=1)
        right_df = pd.concat(right_value_series, axis=1)

        if len(argspec.args) == 2:
            result = f(left_df, right_df)
        elif len(argspec.args) == 3:
            key_series = left_key_series if not left_df.empty else right_key_series
            key = tuple(s[0] for s in key_series)
            result = f(key, left_df, right_df)
        verify_pandas_result(
            result, return_type, _assign_cols_by_name, truncate_return_schema=False
        )

        return result

    arrow_return_type = to_arrow_type(return_type, _use_large_var_types)
    return lambda kl, vl, kr, vr: [(wrapped(kl, vl, kr, vr), arrow_return_type)]


def verify_arrow_result(result, assign_cols_by_name, expected_cols_and_types):
    # the types of the fields have to be identical to return type
    # an empty table can have no columns; if there are columns, they have to match
    if result.num_columns != 0 or result.num_rows != 0:
        # columns are either mapped by name or position
        if assign_cols_by_name:
            actual_cols_and_types = {
                name: dataType for name, dataType in zip(result.schema.names, result.schema.types)
            }
            missing = sorted(
                list(set(expected_cols_and_types.keys()).difference(actual_cols_and_types.keys()))
            )
            extra = sorted(
                list(set(actual_cols_and_types.keys()).difference(expected_cols_and_types.keys()))
            )

            if missing or extra:
                missing = f" Missing: {', '.join(missing)}." if missing else ""
                extra = f" Unexpected: {', '.join(extra)}." if extra else ""

                raise PySparkRuntimeError(
                    errorClass="RESULT_COLUMNS_MISMATCH_FOR_ARROW_UDF",
                    messageParameters={
                        "missing": missing,
                        "extra": extra,
                    },
                )

            column_types = [
                (name, expected_cols_and_types[name], actual_cols_and_types[name])
                for name in sorted(expected_cols_and_types.keys())
            ]
        else:
            actual_cols_and_types = [
                (name, dataType) for name, dataType in zip(result.schema.names, result.schema.types)
            ]
            column_types = [
                (expected_name, expected_type, actual_type)
                for (expected_name, expected_type), (actual_name, actual_type) in zip(
                    expected_cols_and_types, actual_cols_and_types
                )
            ]

        type_mismatch = [
            (name, expected, actual)
            for name, expected, actual in column_types
            if actual != expected
        ]

        if type_mismatch:
            raise PySparkRuntimeError(
                errorClass="RESULT_TYPE_MISMATCH_FOR_ARROW_UDF",
                messageParameters={
                    "mismatch": ", ".join(
                        "column '{}' (expected {}, actual {})".format(name, expected, actual)
                        for name, expected, actual in type_mismatch
                    )
                },
            )


def verify_arrow_table(table, assign_cols_by_name, expected_cols_and_types):
    import pyarrow as pa

    if not isinstance(table, pa.Table):
        raise PySparkTypeError(
            errorClass="UDF_RETURN_TYPE",
            messageParameters={
                "expected": "pyarrow.Table",
                "actual": type(table).__name__,
            },
        )

    verify_arrow_result(table, assign_cols_by_name, expected_cols_and_types)


def verify_arrow_batch(batch, assign_cols_by_name, expected_cols_and_types):
    import pyarrow as pa

    if not isinstance(batch, pa.RecordBatch):
        raise PySparkTypeError(
            errorClass="UDF_RETURN_TYPE",
            messageParameters={
                "expected": "pyarrow.RecordBatch",
                "actual": type(batch).__name__,
            },
        )

    verify_arrow_result(batch, assign_cols_by_name, expected_cols_and_types)


def wrap_grouped_map_arrow_udf(f, return_type, argspec, runner_conf):
    import pyarrow as pa

    _assign_cols_by_name = assign_cols_by_name(runner_conf)

    if _assign_cols_by_name:
        expected_cols_and_types = {
            col.name: to_arrow_type(col.dataType) for col in return_type.fields
        }
    else:
        expected_cols_and_types = [
            (col.name, to_arrow_type(col.dataType)) for col in return_type.fields
        ]

    def wrapped(key_batch, value_batches):
        value_table = pa.Table.from_batches(value_batches)
        if len(argspec.args) == 1:
            result = f(value_table)
        elif len(argspec.args) == 2:
            key = tuple(c[0] for c in key_batch.columns)
            result = f(key, value_table)

        verify_arrow_table(result, _assign_cols_by_name, expected_cols_and_types)

        yield from result.to_batches()

    arrow_return_type = to_arrow_type(return_type, use_large_var_types(runner_conf))
    return lambda k, v: (wrapped(k, v), arrow_return_type)


def wrap_grouped_map_arrow_iter_udf(f, return_type, argspec, runner_conf):
    _assign_cols_by_name = assign_cols_by_name(runner_conf)

    if _assign_cols_by_name:
        expected_cols_and_types = {
            col.name: to_arrow_type(col.dataType) for col in return_type.fields
        }
    else:
        expected_cols_and_types = [
            (col.name, to_arrow_type(col.dataType)) for col in return_type.fields
        ]

    def wrapped(key_batch, value_batches):
        if len(argspec.args) == 1:
            result = f(value_batches)
        elif len(argspec.args) == 2:
            key = tuple(c[0] for c in key_batch.columns)
            result = f(key, value_batches)

        def verify_element(batch):
            verify_arrow_batch(batch, _assign_cols_by_name, expected_cols_and_types)
            return batch

        yield from map(verify_element, result)

    arrow_return_type = to_arrow_type(return_type, use_large_var_types(runner_conf))
    return lambda k, v: (wrapped(k, v), arrow_return_type)


def wrap_grouped_map_pandas_udf(f, return_type, argspec, runner_conf):
    _use_large_var_types = use_large_var_types(runner_conf)
    _assign_cols_by_name = assign_cols_by_name(runner_conf)

    def wrapped(key_series, value_series):
        import pandas as pd

        if len(argspec.args) == 1:
            result = f(pd.concat(value_series, axis=1))
        elif len(argspec.args) == 2:
            key = tuple(s[0] for s in key_series)
            result = f(key, pd.concat(value_series, axis=1))
        verify_pandas_result(
            result, return_type, _assign_cols_by_name, truncate_return_schema=False
        )

        return result

    arrow_return_type = to_arrow_type(return_type, _use_large_var_types)
    return lambda k, v: [(wrapped(k, v), arrow_return_type)]


def wrap_grouped_map_pandas_iter_udf(f, return_type, argspec, runner_conf):
    _use_large_var_types = use_large_var_types(runner_conf)
    _assign_cols_by_name = assign_cols_by_name(runner_conf)

    def wrapped(key_series_list, value_series_gen):
        import pandas as pd

        # value_series_gen is a generator that yields multiple lists of Series (one per batch)
        # Convert each list of Series into a DataFrame
        def dataframe_iter():
            for value_series in value_series_gen:
                yield pd.concat(value_series, axis=1)

        # Extract key from the first batch
        if len(argspec.args) == 1:
            result = f(dataframe_iter())
        elif len(argspec.args) == 2:
            # key_series_list is a list of Series for the key columns from the first batch
            key = tuple(s[0] for s in key_series_list)
            result = f(key, dataframe_iter())

        def verify_element(df):
            verify_pandas_result(
                df, return_type, _assign_cols_by_name, truncate_return_schema=False
            )
            return df

        yield from map(verify_element, result)

    arrow_return_type = to_arrow_type(return_type, _use_large_var_types)
    return lambda k, v: (wrapped(k, v), arrow_return_type)


def wrap_grouped_transform_with_state_pandas_udf(f, return_type, runner_conf):
    def wrapped(stateful_processor_api_client, mode, key, value_series_gen):
        result_iter = f(stateful_processor_api_client, mode, key, value_series_gen)

        # TODO(SPARK-49100): add verification that elements in result_iter are
        # indeed of type pd.DataFrame and confirm to assigned cols

        return result_iter

    arrow_return_type = to_arrow_type(return_type, use_large_var_types(runner_conf))
    return lambda p, m, k, v: [(wrapped(p, m, k, v), arrow_return_type)]


def wrap_grouped_transform_with_state_pandas_init_state_udf(f, return_type, runner_conf):
    def wrapped(stateful_processor_api_client, mode, key, value_series_gen):
        import pandas as pd

        state_values_gen, init_states_gen = itertools.tee(value_series_gen, 2)
        state_values = (df for x, _ in state_values_gen if not (df := pd.concat(x, axis=1)).empty)
        init_states = (df for _, x in init_states_gen if not (df := pd.concat(x, axis=1)).empty)

        result_iter = f(stateful_processor_api_client, mode, key, state_values, init_states)

        # TODO(SPARK-49100): add verification that elements in result_iter are
        # indeed of type pd.DataFrame and confirm to assigned cols

        return result_iter

    arrow_return_type = to_arrow_type(return_type, use_large_var_types(runner_conf))
    return lambda p, m, k, v: [(wrapped(p, m, k, v), arrow_return_type)]


def wrap_grouped_transform_with_state_udf(f, return_type, runner_conf):
    def wrapped(stateful_processor_api_client, mode, key, values):
        result_iter = f(stateful_processor_api_client, mode, key, values)

        # TODO(SPARK-XXXXX): add verification that elements in result_iter are
        # indeed of type Row and confirm to assigned cols

        return result_iter

    arrow_return_type = to_arrow_type(return_type, use_large_var_types(runner_conf))
    return lambda p, m, k, v: [(wrapped(p, m, k, v), arrow_return_type)]


def wrap_grouped_transform_with_state_init_state_udf(f, return_type, runner_conf):
    def wrapped(stateful_processor_api_client, mode, key, values):
        if mode == TransformWithStateInPandasFuncMode.PROCESS_DATA:
            values_gen = values[0]
            init_states_gen = values[1]
        else:
            values_gen = iter([])
            init_states_gen = iter([])

        result_iter = f(stateful_processor_api_client, mode, key, values_gen, init_states_gen)

        # TODO(SPARK-XXXXX): add verification that elements in result_iter are
        # indeed of type pd.DataFrame and confirm to assigned cols

        return result_iter

    arrow_return_type = to_arrow_type(return_type, use_large_var_types(runner_conf))
    return lambda p, m, k, v: [(wrapped(p, m, k, v), arrow_return_type)]


def wrap_grouped_map_pandas_udf_with_state(f, return_type, runner_conf):
    """
    Provides a new lambda instance wrapping user function of applyInPandasWithState.

    The lambda instance receives (key series, iterator of value series, state) and performs
    some conversion to be adapted with the signature of user function.

    See the function doc of inner function `wrapped` for more details on what adapter does.
    See the function doc of `mapper` function for
    `eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE` for more details on
    the input parameters of lambda function.

    Along with the returned iterator, the lambda instance will also produce the return_type as
    converted to the arrow schema.
    """
    _use_large_var_types = use_large_var_types(runner_conf)

    def wrapped(key_series, value_series_gen, state):
        """
        Provide an adapter of the user function performing below:

        - Extract the first value of all columns in key series and produce as a tuple.
        - If the state has timed out, call the user function with empty pandas DataFrame.
        - If not, construct a new generator which converts each element of value series to
          pandas DataFrame (lazy evaluation), and call the user function with the generator
        - Verify each element of returned iterator to check the schema of pandas DataFrame.
        """
        import pandas as pd

        key = tuple(s[0] for s in key_series)

        if state.hasTimedOut:
            # Timeout processing pass empty iterator. Here we return an empty DataFrame instead.
            values = [
                pd.DataFrame(columns=pd.concat(next(value_series_gen), axis=1).columns),
            ]
        else:
            values = (pd.concat(x, axis=1) for x in value_series_gen)

        result_iter = f(key, values, state)

        def verify_element(result):
            if not isinstance(result, pd.DataFrame):
                raise PySparkTypeError(
                    errorClass="UDF_RETURN_TYPE",
                    messageParameters={
                        "expected": "iterator of pandas.DataFrame",
                        "actual": "iterator of {}".format(type(result).__name__),
                    },
                )
            # the number of columns of result have to match the return type
            # but it is fine for result to have no columns at all if it is empty
            if not (
                len(result.columns) == len(return_type)
                or (len(result.columns) == 0 and result.empty)
            ):
                raise PySparkRuntimeError(
                    errorClass="RESULT_LENGTH_MISMATCH_FOR_PANDAS_UDF",
                    messageParameters={
                        "expected": str(len(return_type)),
                        "actual": str(len(result.columns)),
                    },
                )

            return result

        if isinstance(result_iter, pd.DataFrame):
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={
                    "expected": "iterable of pandas.DataFrame",
                    "actual": type(result_iter).__name__,
                },
            )

        try:
            iter(result_iter)
        except TypeError:
            raise PySparkTypeError(
                errorClass="UDF_RETURN_TYPE",
                messageParameters={"expected": "iterable", "actual": type(result_iter).__name__},
            )

        result_iter_with_validation = (verify_element(x) for x in result_iter)

        return (
            result_iter_with_validation,
            state,
        )

    arrow_return_type = to_arrow_type(return_type, _use_large_var_types)
    return lambda k, v, s: [(wrapped(k, v, s), arrow_return_type)]


def wrap_grouped_agg_pandas_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def wrapped(*series):
        import pandas as pd

        result = func(*series)
        return pd.Series([result])

    return (
        args_kwargs_offsets,
        lambda *a: (wrapped(*a), arrow_return_type),
    )


def wrap_grouped_agg_arrow_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def wrapped(*series):
        import pyarrow as pa

        result = func(*series)
        return pa.array([result])

    return (
        args_kwargs_offsets,
        lambda *a: (wrapped(*a), arrow_return_type),
    )


def wrap_window_agg_pandas_udf(
    f, args_offsets, kwargs_offsets, return_type, runner_conf, udf_index
):
    window_bound_types_str = runner_conf.get("window_bound_types")
    window_bound_type = [t.strip().lower() for t in window_bound_types_str.split(",")][udf_index]
    if window_bound_type == "bounded":
        return wrap_bounded_window_agg_pandas_udf(
            f, args_offsets, kwargs_offsets, return_type, runner_conf
        )
    elif window_bound_type == "unbounded":
        return wrap_unbounded_window_agg_pandas_udf(
            f, args_offsets, kwargs_offsets, return_type, runner_conf
        )
    else:
        raise PySparkRuntimeError(
            errorClass="INVALID_WINDOW_BOUND_TYPE",
            messageParameters={
                "window_bound_type": window_bound_type,
            },
        )


def wrap_window_agg_arrow_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf, udf_index):
    window_bound_types_str = runner_conf.get("window_bound_types")
    window_bound_type = [t.strip().lower() for t in window_bound_types_str.split(",")][udf_index]
    if window_bound_type == "bounded":
        return wrap_bounded_window_agg_arrow_udf(
            f, args_offsets, kwargs_offsets, return_type, runner_conf
        )
    elif window_bound_type == "unbounded":
        return wrap_unbounded_window_agg_arrow_udf(
            f, args_offsets, kwargs_offsets, return_type, runner_conf
        )
    else:
        raise PySparkRuntimeError(
            errorClass="INVALID_WINDOW_BOUND_TYPE",
            messageParameters={
                "window_bound_type": window_bound_type,
            },
        )


def wrap_unbounded_window_agg_pandas_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    # This is similar to grouped_agg_pandas_udf, the only difference
    # is that window_agg_pandas_udf needs to repeat the return value
    # to match window length, where grouped_agg_pandas_udf just returns
    # the scalar value.
    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def wrapped(*series):
        import pandas as pd

        result = func(*series)
        return pd.Series([result]).repeat(len(series[0]))

    return (
        args_kwargs_offsets,
        lambda *a: (wrapped(*a), arrow_return_type),
    )


def wrap_unbounded_window_agg_arrow_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets, kwargs_offsets)

    # This is similar to wrap_unbounded_window_agg_pandas_udf, the only difference
    # is that this function is for arrow udf.
    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def wrapped(*series):
        import pyarrow as pa

        result = func(*series)
        return pa.repeat(result, len(series[0]))

    return (
        args_kwargs_offsets,
        lambda *a: (wrapped(*a), arrow_return_type),
    )


def wrap_bounded_window_agg_pandas_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    # args_offsets should have at least 2 for begin_index, end_index.
    assert len(args_offsets) >= 2, len(args_offsets)
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets[2:], kwargs_offsets)

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def wrapped(begin_index, end_index, *series):
        import pandas as pd

        result = []

        # Index operation is faster on np.ndarray,
        # So we turn the index series into np array
        # here for performance
        begin_array = begin_index.values
        end_array = end_index.values

        for i in range(len(begin_array)):
            # Note: Create a slice from a series for each window is
            #       actually pretty expensive. However, there
            #       is no easy way to reduce cost here.
            # Note: s.iloc[i : j] is about 30% faster than s[i: j], with
            #       the caveat that the created slices shares the same
            #       memory with s. Therefore, user are not allowed to
            #       change the value of input series inside the window
            #       function. It is rare that user needs to modify the
            #       input series in the window function, and therefore,
            #       it is be a reasonable restriction.
            # Note: Calling reset_index on the slices will increase the cost
            #       of creating slices by about 100%. Therefore, for performance
            #       reasons we don't do it here.
            series_slices = [s.iloc[begin_array[i] : end_array[i]] for s in series]
            result.append(func(*series_slices))
        return pd.Series(result)

    return (
        args_offsets[:2] + args_kwargs_offsets,
        lambda *a: (wrapped(*a), arrow_return_type),
    )


def wrap_bounded_window_agg_arrow_udf(f, args_offsets, kwargs_offsets, return_type, runner_conf):
    # args_offsets should have at least 2 for begin_index, end_index.
    assert len(args_offsets) >= 2, len(args_offsets)
    func, args_kwargs_offsets = wrap_kwargs_support(f, args_offsets[2:], kwargs_offsets)

    arrow_return_type = to_arrow_type(
        return_type, prefers_large_types=use_large_var_types(runner_conf)
    )

    def wrapped(begin_index, end_index, *series):
        import pyarrow as pa

        assert isinstance(begin_index, pa.Int32Array), type(begin_index)
        assert isinstance(end_index, pa.Int32Array), type(end_index)

        result = []
        for i in range(len(begin_index)):
            offset = begin_index[i].as_py()
            length = end_index[i].as_py() - offset
            series_slices = [s.slice(offset=offset, length=length) for s in series]
            result.append(func(*series_slices))
        return pa.array(result)

    return (
        args_offsets[:2] + args_kwargs_offsets,
        lambda *a: (wrapped(*a), arrow_return_type),
    )


def wrap_kwargs_support(f, args_offsets, kwargs_offsets):
    if len(kwargs_offsets):
        keys = list(kwargs_offsets.keys())

        len_args_offsets = len(args_offsets)
        if len_args_offsets > 0:

            def func(*args):
                return f(*args[:len_args_offsets], **dict(zip(keys, args[len_args_offsets:])))

        else:

            def func(*args):
                return f(**dict(zip(keys, args)))

        return func, args_offsets + [kwargs_offsets[key] for key in keys]
    else:
        return f, args_offsets


def _is_iter_based(eval_type: int) -> bool:
    return eval_type in (
        PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF,
        PythonEvalType.SQL_SCALAR_ARROW_ITER_UDF,
        PythonEvalType.SQL_MAP_PANDAS_ITER_UDF,
        PythonEvalType.SQL_MAP_ARROW_ITER_UDF,
        PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE,
        PythonEvalType.SQL_GROUPED_MAP_ARROW_ITER_UDF,
        PythonEvalType.SQL_GROUPED_MAP_PANDAS_ITER_UDF,
    )


def wrap_perf_profiler(f, eval_type, result_id):
    import cProfile
    import pstats

    from pyspark.sql.profiler import ProfileResultsParam

    accumulator = _deserialize_accumulator(
        SpecialAccumulatorIds.SQL_UDF_PROFIER, None, ProfileResultsParam
    )

    if _is_iter_based(eval_type):

        def profiling_func(*args, **kwargs):
            iterator = iter(f(*args, **kwargs))
            pr = cProfile.Profile()
            while True:
                try:
                    with pr:
                        item = next(iterator)
                    yield item
                except StopIteration:
                    break

            st = pstats.Stats(pr)
            st.stream = None  # make it picklable
            st.strip_dirs()

            accumulator.add({result_id: (st, None)})

    else:

        def profiling_func(*args, **kwargs):
            with cProfile.Profile() as pr:
                ret = f(*args, **kwargs)
            st = pstats.Stats(pr)
            st.stream = None  # make it picklable
            st.strip_dirs()

            accumulator.add({result_id: (st, None)})

            return ret

    return profiling_func


def wrap_memory_profiler(f, eval_type, result_id):
    from pyspark.sql.profiler import ProfileResultsParam
    from pyspark.profiler import UDFLineProfilerV2

    if not has_memory_profiler:
        return f

    accumulator = _deserialize_accumulator(
        SpecialAccumulatorIds.SQL_UDF_PROFIER, None, ProfileResultsParam
    )

    if _is_iter_based(eval_type):

        def profiling_func(*args, **kwargs):
            profiler = UDFLineProfilerV2()
            profiler.add_function(f)

            iterator = iter(f(*args, **kwargs))

            while True:
                try:
                    with profiler:
                        item = next(iterator)
                    yield item
                except StopIteration:
                    break

            codemap_dict = {
                filename: list(line_iterator)
                for filename, line_iterator in profiler.code_map.items()
            }
            accumulator.add({result_id: (None, codemap_dict)})

    else:

        def profiling_func(*args, **kwargs):
            profiler = UDFLineProfilerV2()
            profiler.add_function(f)

            with profiler:
                ret = f(*args, **kwargs)

            codemap_dict = {
                filename: list(line_iterator)
                for filename, line_iterator in profiler.code_map.items()
            }
            accumulator.add({result_id: (None, codemap_dict)})
            return ret

    return profiling_func


def read_single_udf(pickleSer, infile, eval_type, runner_conf, udf_index, profiler):
    num_arg = read_int(infile)

    if eval_type in (
        PythonEvalType.SQL_BATCHED_UDF,
        PythonEvalType.SQL_ARROW_BATCHED_UDF,
        PythonEvalType.SQL_SCALAR_PANDAS_UDF,
        PythonEvalType.SQL_SCALAR_ARROW_UDF,
        PythonEvalType.SQL_GROUPED_AGG_PANDAS_UDF,
        PythonEvalType.SQL_WINDOW_AGG_PANDAS_UDF,
        PythonEvalType.SQL_WINDOW_AGG_ARROW_UDF,
        # The below doesn't support named argument, but shares the same protocol.
        PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF,
        PythonEvalType.SQL_SCALAR_ARROW_ITER_UDF,
        PythonEvalType.SQL_GROUPED_AGG_ARROW_UDF,
    ):
        args_offsets = []
        kwargs_offsets = {}
        for _ in range(num_arg):
            offset = read_int(infile)
            if read_bool(infile):
                name = utf8_deserializer.loads(infile)
                kwargs_offsets[name] = offset
            else:
                args_offsets.append(offset)
    else:
        args_offsets = [read_int(infile) for i in range(num_arg)]
        kwargs_offsets = {}

    chained_func = None
    for i in range(read_int(infile)):
        f, return_type = read_command(pickleSer, infile)
        if chained_func is None:
            chained_func = f
        else:
            chained_func = chain(chained_func, f)

    if profiler == "perf":
        result_id = read_long(infile)

        profiling_func = wrap_perf_profiler(chained_func, eval_type, result_id)

    elif profiler == "memory":
        result_id = read_long(infile)

        profiling_func = wrap_memory_profiler(chained_func, eval_type, result_id)
    else:
        profiling_func = chained_func

    if eval_type in (
        PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF,
        PythonEvalType.SQL_ARROW_BATCHED_UDF,
    ):
        func = profiling_func
    else:
        # make sure StopIteration's raised in the user code are not ignored
        # when they are processed in a for loop, raise them as RuntimeError's instead
        func = fail_on_stopiteration(profiling_func)

    # the last returnType will be the return type of UDF
    if eval_type == PythonEvalType.SQL_SCALAR_PANDAS_UDF:
        return wrap_scalar_pandas_udf(func, args_offsets, kwargs_offsets, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_SCALAR_ARROW_UDF:
        return wrap_scalar_arrow_udf(func, args_offsets, kwargs_offsets, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_ARROW_BATCHED_UDF:
        return wrap_arrow_batch_udf(func, args_offsets, kwargs_offsets, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF:
        return args_offsets, wrap_pandas_batch_iter_udf(func, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_SCALAR_ARROW_ITER_UDF:
        return args_offsets, wrap_arrow_array_iter_udf(func, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_MAP_PANDAS_ITER_UDF:
        return args_offsets, wrap_pandas_batch_iter_udf(func, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_MAP_ARROW_ITER_UDF:
        return args_offsets, wrap_arrow_batch_iter_udf(func, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF:
        argspec = inspect.getfullargspec(chained_func)  # signature was lost when wrapping it
        return args_offsets, wrap_grouped_map_pandas_udf(func, return_type, argspec, runner_conf)
    elif eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_ITER_UDF:
        argspec = inspect.getfullargspec(chained_func)  # signature was lost when wrapping it
        return args_offsets, wrap_grouped_map_pandas_iter_udf(
            func, return_type, argspec, runner_conf
        )
    elif eval_type == PythonEvalType.SQL_GROUPED_MAP_ARROW_UDF:
        argspec = inspect.getfullargspec(chained_func)  # signature was lost when wrapping it
        return args_offsets, wrap_grouped_map_arrow_udf(func, return_type, argspec, runner_conf)
    elif eval_type == PythonEvalType.SQL_GROUPED_MAP_ARROW_ITER_UDF:
        argspec = inspect.getfullargspec(chained_func)  # signature was lost when wrapping it
        return args_offsets, wrap_grouped_map_arrow_iter_udf(
            func, return_type, argspec, runner_conf
        )
    elif eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE:
        return args_offsets, wrap_grouped_map_pandas_udf_with_state(func, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_UDF:
        return args_offsets, wrap_grouped_transform_with_state_pandas_udf(
            func, return_type, runner_conf
        )
    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_INIT_STATE_UDF:
        return args_offsets, wrap_grouped_transform_with_state_pandas_init_state_udf(
            func, return_type, runner_conf
        )
    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_UDF:
        return args_offsets, wrap_grouped_transform_with_state_udf(func, return_type, runner_conf)
    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_INIT_STATE_UDF:
        return args_offsets, wrap_grouped_transform_with_state_init_state_udf(
            func, return_type, runner_conf
        )
    elif eval_type == PythonEvalType.SQL_COGROUPED_MAP_PANDAS_UDF:
        argspec = inspect.getfullargspec(chained_func)  # signature was lost when wrapping it
        return args_offsets, wrap_cogrouped_map_pandas_udf(func, return_type, argspec, runner_conf)
    elif eval_type == PythonEvalType.SQL_COGROUPED_MAP_ARROW_UDF:
        argspec = inspect.getfullargspec(chained_func)  # signature was lost when wrapping it
        return args_offsets, wrap_cogrouped_map_arrow_udf(func, return_type, argspec, runner_conf)
    elif eval_type == PythonEvalType.SQL_GROUPED_AGG_PANDAS_UDF:
        return wrap_grouped_agg_pandas_udf(
            func, args_offsets, kwargs_offsets, return_type, runner_conf
        )
    elif eval_type == PythonEvalType.SQL_GROUPED_AGG_ARROW_UDF:
        return wrap_grouped_agg_arrow_udf(
            func, args_offsets, kwargs_offsets, return_type, runner_conf
        )
    elif eval_type == PythonEvalType.SQL_WINDOW_AGG_PANDAS_UDF:
        return wrap_window_agg_pandas_udf(
            func, args_offsets, kwargs_offsets, return_type, runner_conf, udf_index
        )
    elif eval_type == PythonEvalType.SQL_WINDOW_AGG_ARROW_UDF:
        return wrap_window_agg_arrow_udf(
            func, args_offsets, kwargs_offsets, return_type, runner_conf, udf_index
        )
    elif eval_type == PythonEvalType.SQL_BATCHED_UDF:
        return wrap_udf(func, args_offsets, kwargs_offsets, return_type)
    else:
        raise ValueError("Unknown eval type: {}".format(eval_type))


# Used by SQL_GROUPED_MAP_PANDAS_UDF, SQL_GROUPED_MAP_ARROW_UDF,
# SQL_COGROUPED_MAP_PANDAS_UDF, SQL_COGROUPED_MAP_ARROW_UDF,
# SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE,
# SQL_SCALAR_PANDAS_UDF and SQL_ARROW_BATCHED_UDF when
# returning StructType
def assign_cols_by_name(runner_conf):
    return (
        runner_conf.get(
            "spark.sql.legacy.execution.pandas.groupedMap.assignColumnsByName", "true"
        ).lower()
        == "true"
    )


def use_large_var_types(runner_conf):
    return runner_conf.get("spark.sql.execution.arrow.useLargeVarTypes", "false").lower() == "true"


def use_legacy_pandas_udf_conversion(runner_conf):
    return (
        runner_conf.get(
            "spark.sql.legacy.execution.pythonUDF.pandas.conversion.enabled", "false"
        ).lower()
        == "true"
    )


# Read and process a serialized user-defined table function (UDTF) from a socket.
# It expects the UDTF to be in a specific format and performs various checks to
# ensure the UDTF is valid. This function also prepares a mapper function for applying
# the UDTF logic to input rows.
def read_udtf(pickleSer, infile, eval_type):
    prefers_large_var_types = False
    legacy_pandas_conversion = False
    binary_as_bytes = True

    if eval_type == PythonEvalType.SQL_ARROW_TABLE_UDF:
        runner_conf = {}
        # Load conf used for arrow evaluation.
        num_conf = read_int(infile)
        for i in range(num_conf):
            k = utf8_deserializer.loads(infile)
            v = utf8_deserializer.loads(infile)
            runner_conf[k] = v
        prefers_large_var_types = use_large_var_types(runner_conf)
        legacy_pandas_conversion = (
            runner_conf.get(
                "spark.sql.legacy.execution.pythonUDTF.pandas.conversion.enabled", "false"
            ).lower()
            == "true"
        )
        binary_as_bytes = (
            runner_conf.get("spark.sql.execution.pyspark.binaryAsBytes", "true").lower() == "true"
        )
        input_types = [
            field.dataType for field in _parse_datatype_json_string(utf8_deserializer.loads(infile))
        ]
        if legacy_pandas_conversion:
            # NOTE: if timezone is set here, that implies respectSessionTimeZone is True
            safecheck = (
                runner_conf.get(
                    "spark.sql.execution.pandas.convertToArrowArraySafely", "false"
                ).lower()
                == "true"
            )
            int_to_decimal_coercion_enabled = (
                runner_conf.get(
                    "spark.sql.execution.pythonUDF.pandas.intToDecimalCoercionEnabled", "false"
                ).lower()
                == "true"
            )
            timezone = runner_conf.get("spark.sql.session.timeZone", None)
            ser = ArrowStreamPandasUDTFSerializer(
                timezone,
                safecheck,
                input_types=input_types,
                int_to_decimal_coercion_enabled=int_to_decimal_coercion_enabled,
            )
        else:
            ser = ArrowStreamUDTFSerializer()
    elif eval_type == PythonEvalType.SQL_ARROW_UDTF:
        runner_conf = {}
        num_conf = read_int(infile)
        for i in range(num_conf):
            k = utf8_deserializer.loads(infile)
            v = utf8_deserializer.loads(infile)
            runner_conf[k] = v
        prefers_large_var_types = use_large_var_types(runner_conf)
        # Read the table argument offsets
        num_table_arg_offsets = read_int(infile)
        table_arg_offsets = [read_int(infile) for _ in range(num_table_arg_offsets)]
        # Use PyArrow-native serializer for Arrow UDTFs with potential UDT support
        ser = ArrowStreamArrowUDTFSerializer(table_arg_offsets=table_arg_offsets)
    else:
        # Each row is a group so do not batch but send one by one.
        ser = BatchedSerializer(CPickleSerializer(), 1)

    # See 'PythonUDTFRunner.PythonUDFWriterThread.writeCommand'
    num_arg = read_int(infile)
    args_offsets = []
    kwargs_offsets = {}
    for _ in range(num_arg):
        offset = read_int(infile)
        if read_bool(infile):
            name = utf8_deserializer.loads(infile)
            kwargs_offsets[name] = offset
        else:
            args_offsets.append(offset)
    num_partition_child_indexes = read_int(infile)
    partition_child_indexes = [read_int(infile) for i in range(num_partition_child_indexes)]
    has_pickled_analyze_result = read_bool(infile)
    if has_pickled_analyze_result:
        pickled_analyze_result = pickleSer._read_with_length(infile)
    else:
        pickled_analyze_result = None
    # Initially we assume that the UDTF __init__ method accepts the pickled AnalyzeResult,
    # although we may set this to false later if we find otherwise.
    handler = read_command(pickleSer, infile)
    if not isinstance(handler, type):
        raise PySparkRuntimeError(
            f"Invalid UDTF handler type. Expected a class (type 'type'), but "
            f"got an instance of {type(handler).__name__}."
        )

    return_type = _parse_datatype_json_string(utf8_deserializer.loads(infile))
    if not isinstance(return_type, StructType):
        raise PySparkRuntimeError(
            f"The return type of a UDTF must be a struct type, but got {type(return_type)}."
        )
    udtf_name = utf8_deserializer.loads(infile)

    # Update the handler that creates a new UDTF instance to first try calling the UDTF constructor
    # with one argument containing the previous AnalyzeResult. If that fails, then try a constructor
    # with no arguments. In this way each UDTF class instance can decide if it wants to inspect the
    # AnalyzeResult.
    udtf_init_args = inspect.getfullargspec(handler)
    if has_pickled_analyze_result:
        if len(udtf_init_args.args) > 2:
            raise PySparkRuntimeError(
                errorClass="UDTF_CONSTRUCTOR_INVALID_IMPLEMENTS_ANALYZE_METHOD",
                messageParameters={"name": udtf_name},
            )
        elif len(udtf_init_args.args) == 2:
            prev_handler = handler

            def construct_udtf():
                # Here we pass the AnalyzeResult to the UDTF's __init__ method.
                return prev_handler(dataclasses.replace(pickled_analyze_result))

            handler = construct_udtf
    elif len(udtf_init_args.args) > 1:
        raise PySparkRuntimeError(
            errorClass="UDTF_CONSTRUCTOR_INVALID_NO_ANALYZE_METHOD",
            messageParameters={"name": udtf_name},
        )

    class UDTFWithPartitions:
        """
        This implements the logic of a UDTF that accepts an input TABLE argument with one or more
        PARTITION BY expressions.

        For example, let's assume we have a table like:
            CREATE TABLE t (c1 INT, c2 INT) USING delta;
        Then for the following queries:
            SELECT * FROM my_udtf(TABLE (t) PARTITION BY c1, c2);
            The partition_child_indexes will be: 0, 1.
            SELECT * FROM my_udtf(TABLE (t) PARTITION BY c1, c2 + 4);
            The partition_child_indexes will be: 0, 2 (where we add a projection for "c2 + 4").
        """

        def __init__(self, create_udtf: Callable, partition_child_indexes: list):
            """
            Creates a new instance of this class to wrap the provided UDTF with another one that
            checks the values of projected partitioning expressions on consecutive rows to figure
            out when the partition boundaries change.

            Parameters
            ----------
            create_udtf: function
                Function to create a new instance of the UDTF to be invoked.
            partition_child_indexes: list
                List of integers identifying zero-based indexes of the columns of the input table
                that contain projected partitioning expressions. This class will inspect these
                values for each pair of consecutive input rows. When they change, this indicates
                the boundary between two partitions, and we will invoke the 'terminate' method on
                the UDTF class instance and then destroy it and create a new one to implement the
                desired partitioning semantics.
            """
            self._create_udtf: Callable = create_udtf
            self._udtf = create_udtf()
            self._prev_arguments: list = list()
            self._partition_child_indexes: list = partition_child_indexes
            self._eval_raised_skip_rest_of_input_table: bool = False

        def eval(self, *args, **kwargs) -> Iterator:
            changed_partitions = self._check_partition_boundaries(
                list(args) + list(kwargs.values())
            )
            if changed_partitions:
                if hasattr(self._udtf, "terminate"):
                    result = self._udtf.terminate()
                    if result is not None:
                        for row in result:
                            yield row
                self._udtf = self._create_udtf()
                self._eval_raised_skip_rest_of_input_table = False
            if self._udtf.eval is not None and not self._eval_raised_skip_rest_of_input_table:
                # Filter the arguments to exclude projected PARTITION BY values added by Catalyst.
                filtered_args = [self._remove_partition_by_exprs(arg) for arg in args]
                filtered_kwargs = {
                    key: self._remove_partition_by_exprs(value) for (key, value) in kwargs.items()
                }
                try:
                    result = self._udtf.eval(*filtered_args, **filtered_kwargs)
                    if result is not None:
                        for row in result:
                            yield row
                except SkipRestOfInputTableException:
                    # If the 'eval' method raised this exception, then we should skip the rest of
                    # the rows in the current partition. Set this field to True here and then for
                    # each subsequent row in the partition, we will skip calling the 'eval' method
                    # until we see a change in the partition boundaries.
                    self._eval_raised_skip_rest_of_input_table = True

        def terminate(self) -> Iterator:
            if hasattr(self._udtf, "terminate"):
                return self._udtf.terminate()
            return iter(())

        def cleanup(self) -> None:
            if hasattr(self._udtf, "cleanup"):
                self._udtf.cleanup()

        def _check_partition_boundaries(self, arguments: list) -> bool:
            result = False
            if len(self._prev_arguments) > 0:
                cur_table_arg = self._get_table_arg(arguments)
                prev_table_arg = self._get_table_arg(self._prev_arguments)
                cur_partitions_args = []
                prev_partitions_args = []
                for i in self._partition_child_indexes:
                    cur_partitions_args.append(cur_table_arg[i])
                    prev_partitions_args.append(prev_table_arg[i])
                result = any(k != v for k, v in zip(cur_partitions_args, prev_partitions_args))
            self._prev_arguments = arguments
            return result

        def _get_table_arg(self, inputs: list) -> Row:
            return [x for x in inputs if type(x) is Row][0]

        def _remove_partition_by_exprs(self, arg: Any) -> Any:
            if isinstance(arg, Row):
                new_row_keys = []
                new_row_values = []
                for i, (key, value) in enumerate(zip(arg.__fields__, arg)):
                    if i not in self._partition_child_indexes:
                        new_row_keys.append(key)
                        new_row_values.append(value)
                return _create_row(new_row_keys, new_row_values)
            else:
                return arg

    class ArrowUDTFWithPartition:
        """
        Implements logic for an Arrow UDTF (SQL_ARROW_UDTF) that accepts a TABLE argument
        with one or more PARTITION BY expressions.

        Arrow UDTFs receive data as PyArrow RecordBatch objects instead of individual Row
        objects. This wrapper ensures the UDTF's eval() method is called separately for each
        unique partition key value combination.

        How Catalyst handles PARTITION BY and ORDER BY:
        ------------------------------------------------
        When a UDTF is called with PARTITION BY and/or ORDER BY clauses, Catalyst adds
        operations to the physical plan to ensure correct data organization:

        Example SQL:
            SELECT * FROM my_udtf(TABLE(t) PARTITION BY key1, key2 ORDER BY value DESC)

        Physical Plan generated by Catalyst:
            1. Project: Adds partition_by_0 = key1, partition_by_1 = key2 columns
            2. Exchange: hashpartitioning(partition_by_0, partition_by_1, 200)
               - Shuffles data so rows with same partition keys go to same worker
            3. Sort: [partition_by_0 ASC, partition_by_1 ASC, value DESC], local=true
               - First sorts by partition keys to group them together
               - Then sorts by ORDER BY expressions within each partition
               - Local sort (not global) within each worker's data
            4. Project: Creates struct with all columns including partition_by_* columns
            5. ArrowEvalPythonUDTF: Executes this Python UDTF wrapper

        Key guarantee: After the Sort operation, all rows with the same partition key
        values are contiguous within each RecordBatch, allowing efficient boundary detection.

        Example queries:
            SELECT * FROM my_udtf(TABLE (t) PARTITION BY c1);
            partition_child_indexes: [2] (refers to partition_by_0 column at index 2)

            SELECT * FROM my_udtf(TABLE (t) PARTITION BY c1, c2);
            partition_child_indexes: [2, 3] (partition_by_0 and partition_by_1 columns)

            SELECT * FROM my_udtf(TABLE (t) PARTITION BY c1, c2 + 4);
            partition_child_indexes: 0, 2 (adds a projection for "c2 + 4").
        """

        def __init__(self, create_udtf: Callable, partition_child_indexes: list):
            """
            Create a new instance that wraps the provided Arrow UDTF with partitioning
            logic.

            Parameters
            ----------
            create_udtf: function
                Function that creates a new instance of the Arrow UDTF to invoke.
            partition_child_indexes: list
                Zero-based indexes of input-table columns that contain projected
                partitioning expressions.
            """
            self._create_udtf: Callable = create_udtf
            self._udtf = create_udtf()
            self._partition_child_indexes: list = partition_child_indexes
            # Track last partition key from previous batch
            self._last_partition_key: Optional[Tuple[Any, ...]] = None
            self._eval_raised_skip_rest_of_input_table: bool = False

        def eval(self, *args, **kwargs) -> Iterator:
            """Handle partitioning logic for Arrow UDTFs that receive RecordBatch objects."""
            import pyarrow as pa

            # Get the original batch with partition columns
            original_batch = self._get_table_arg(list(args) + list(kwargs.values()))
            if not isinstance(original_batch, pa.RecordBatch):
                # Arrow UDTFs with PARTITION BY must have a TABLE argument that
                # results in a PyArrow RecordBatch
                raise PySparkRuntimeError(
                    errorClass="INVALID_ARROW_UDTF_TABLE_ARGUMENT",
                    messageParameters={
                        "actual_type": str(type(original_batch))
                        if original_batch is not None
                        else "None"
                    },
                )

            # Remove partition columns to get the filtered arguments
            filtered_args = [self._remove_partition_by_exprs(arg) for arg in args]
            filtered_kwargs = {
                key: self._remove_partition_by_exprs(value) for (key, value) in kwargs.items()
            }

            # Get the filtered RecordBatch (without partition columns)
            filtered_batch = self._get_table_arg(filtered_args + list(filtered_kwargs.values()))

            # Process the RecordBatch by partitions
            yield from self._process_arrow_batch_by_partitions(
                original_batch, filtered_batch, filtered_args, filtered_kwargs
            )

        def _process_arrow_batch_by_partitions(
            self, original_batch, filtered_batch, filtered_args, filtered_kwargs
        ) -> Iterator:
            """Process an Arrow RecordBatch that may contain multiple partition key values.

            When using PARTITION BY with Arrow UDTFs, a single RecordBatch from Spark may contain
            rows with different partition key values. For example, with 10 distinct partition keys
            and 2 workers, each worker might receive a batch containing 5 different partition key
            values.

            According to UDTF PARTITION BY semantics, the UDTF's eval() method must be called
            separately for each unique partition key value, not for the entire batch. This method
            handles splitting the batch by partition boundaries and calling the UDTF appropriately.

            The implementation leverages two key properties:
            1. Catalyst guarantees rows with the same partition key are contiguous (pre-sorted)
            2. Arrow's columnar format allows efficient boundary detection

            Parameters:
            -----------
            original_batch : pa.RecordBatch
                The original batch including partition columns, used for detecting boundaries
            filtered_batch : pa.RecordBatch
                The batch with partition columns removed, to be passed to the UDTF
            filtered_args : list
                Arguments with partition columns filtered out
            filtered_kwargs : dict
                Keyword arguments with partition columns filtered out

            Yields:
            -------
            Iterator of pa.Table objects returned by the UDTF's eval() method
            """
            import pyarrow as pa

            # This class should only be used when partition_child_indexes is non-empty
            assert self._partition_child_indexes, (
                "ArrowUDTFWithPartition should only be instantiated when "
                "len(partition_child_indexes) > 0"
            )

            # Detect partition boundaries.
            boundaries = self._detect_partition_boundaries(original_batch)

            # Process each contiguous partition
            for i in range(len(boundaries) - 1):
                start_idx = boundaries[i]
                end_idx = boundaries[i + 1]

                # Get the partition key for this segment
                partition_key = tuple(
                    original_batch.column(idx)[start_idx].as_py()
                    for idx in self._partition_child_indexes
                )

                # Check if this is a continuation of the previous batch's partition
                # TODO: This check is only necessary for the first boundary in each batch.
                # The following boundaries are always for new partitions within the same batch.
                # This could be optimized by only checking i == 0.
                is_new_partition = (
                    self._last_partition_key is not None
                    and partition_key != self._last_partition_key
                )

                if is_new_partition:
                    # Previous partition ended, call terminate
                    if hasattr(self._udtf, "terminate"):
                        terminate_result = self._udtf.terminate()
                        if terminate_result is not None:
                            yield from terminate_result
                    # Create new UDTF instance for new partition
                    self._udtf = self._create_udtf()
                    self._eval_raised_skip_rest_of_input_table = False

                # Slice the filtered batch for this partition
                partition_batch = filtered_batch.slice(start_idx, end_idx - start_idx)

                # Update the last partition key
                self._last_partition_key = partition_key

                # Update filtered args to use the partition batch
                partition_filtered_args = []
                for arg in filtered_args:
                    if isinstance(arg, pa.RecordBatch):
                        partition_filtered_args.append(partition_batch)
                    else:
                        partition_filtered_args.append(arg)

                partition_filtered_kwargs = {}
                for key, value in filtered_kwargs.items():
                    if isinstance(value, pa.RecordBatch):
                        partition_filtered_kwargs[key] = partition_batch
                    else:
                        partition_filtered_kwargs[key] = value

                # Call the UDTF with this partition's data
                if not self._eval_raised_skip_rest_of_input_table:
                    try:
                        result = self._udtf.eval(
                            *partition_filtered_args, **partition_filtered_kwargs
                        )
                        if result is not None:
                            yield from result
                    except SkipRestOfInputTableException:
                        # Skip remaining rows in this partition
                        self._eval_raised_skip_rest_of_input_table = True

            # Don't terminate here - let the next batch or final terminate handle it

        def terminate(self) -> Iterator:
            if hasattr(self._udtf, "terminate"):
                return self._udtf.terminate()
            return iter(())

        def cleanup(self) -> None:
            if hasattr(self._udtf, "cleanup"):
                self._udtf.cleanup()

        def _get_table_arg(self, inputs: list):
            """Get the table argument (RecordBatch) from the inputs list.

            For Arrow UDTFs with TABLE arguments, we can guarantee the table argument
            will be a pa.RecordBatch, not a Row.
            """
            import pyarrow as pa

            # Find all RecordBatch arguments
            batches = [arg for arg in inputs if isinstance(arg, pa.RecordBatch)]

            if len(batches) == 0:
                # No RecordBatch found - this shouldn't happen for Arrow UDTFs with TABLE arguments
                return None
            elif len(batches) == 1:
                return batches[0]
            else:
                # Multiple RecordBatch arguments found - this is unexpected
                raise RuntimeError(
                    f"Expected exactly one pa.RecordBatch argument for TABLE parameter, "
                    f"but found {len(batches)}. Received types: "
                    f"{[type(arg).__name__ for arg in inputs]}"
                )

        def _detect_partition_boundaries(self, batch) -> list:
            """
            Efficiently detect partition boundaries in a batch with contiguous partitions.

            Since Catalyst ensures rows with the same partition key are contiguous,
            we only need to find where partition values change.

            Returns:
                List of indices where each partition starts, plus the total row count.
                For example: [0, 3, 8, 10] means partitions are rows [0:3), [3:8), [8:10)
            """
            boundaries = [0]  # First partition starts at index 0

            if batch.num_rows <= 1:
                boundaries.append(batch.num_rows)
                return boundaries

            # Get partition column arrays
            partition_arrays = [batch.column(i) for i in self._partition_child_indexes]

            # Find boundaries by comparing consecutive rows
            for row_idx in range(1, batch.num_rows):
                # Check if any partition column changed from previous row
                partition_changed = False
                for col_array in partition_arrays:
                    if col_array[row_idx].as_py() != col_array[row_idx - 1].as_py():
                        partition_changed = True
                        break

                if partition_changed:
                    boundaries.append(row_idx)

            boundaries.append(batch.num_rows)  # Last boundary at end
            return boundaries

        def _remove_partition_by_exprs(self, arg: Any) -> Any:
            """
            Remove partition columns from the RecordBatch argument.

            Why this is needed:
            When a UDTF is called with TABLE(t) PARTITION BY expressions, Catalyst transforms
            the data:
            1. Adds complex partition expressions as new columns
               (e.g., "c2 + 4" becomes a new column)
            2. Repartitions data by partition columns using hash partitioning
            3. Sends ALL columns (including partition columns) to the Python worker

            Partition columns serve two purposes:
            - Routing: decide which worker processes which partition
            - Boundary detection: know when one partition ends and another begins

            However, the user's UDTF should only receive the actual table data, not the
            partition columns. This method filters out partition columns before passing
            data to the user's UDTF eval() method.

            Example:
            - User writes: SELECT * FROM udtf(TABLE(t) PARTITION BY c1, c2)
            - Catalyst sends: RecordBatch with [c1, c2, c3, c4],
              partition_child_indexes=[0, 1]
            - This method removes columns at indexes 0, 1 if they are pure partition columns
            - UDTF.eval() receives: RecordBatch with only the non-partition columns
            """
            import pyarrow as pa

            if isinstance(arg, pa.RecordBatch):
                # Remove partition columns from the RecordBatch
                keep_indices = [
                    i
                    for i in range(len(arg.schema.names))
                    if i not in self._partition_child_indexes
                ]
                if keep_indices:
                    # Select only the columns we want to keep
                    keep_arrays = [arg.column(i) for i in keep_indices]
                    keep_names = [arg.schema.names[i] for i in keep_indices]
                    return pa.RecordBatch.from_arrays(keep_arrays, names=keep_names)
                else:
                    # If no columns remain, return an empty RecordBatch with the same number of rows
                    return pa.RecordBatch.from_arrays(
                        [], schema=pa.schema([]), num_rows=arg.num_rows
                    )

            # For non-RecordBatch arguments (like scalar pa.Arrays), return unchanged
            return arg

    # Instantiate the UDTF class.
    try:
        if len(partition_child_indexes) > 0:
            # Determine if this is an Arrow UDTF
            is_arrow_udtf = eval_type == PythonEvalType.SQL_ARROW_UDTF
            if is_arrow_udtf:
                udtf = ArrowUDTFWithPartition(handler, partition_child_indexes)
            else:
                udtf = UDTFWithPartitions(handler, partition_child_indexes)
        else:
            udtf = handler()
    except Exception as e:
        raise PySparkRuntimeError(
            errorClass="UDTF_EXEC_ERROR",
            messageParameters={"method_name": "__init__", "error": str(e)},
        )

    # Validate the UDTF
    if not hasattr(udtf, "eval"):
        raise PySparkRuntimeError(
            "Failed to execute the user defined table function because it has not "
            "implemented the 'eval' method. Please add the 'eval' method and try "
            "the query again."
        )

    # Check that the arguments provided to the UDTF call match the expected parameters defined
    # in the 'eval' method signature.
    try:
        inspect.signature(udtf.eval).bind(*args_offsets, **kwargs_offsets)
    except TypeError as e:
        raise PySparkRuntimeError(
            errorClass="UDTF_EVAL_METHOD_ARGUMENTS_DO_NOT_MATCH_SIGNATURE",
            messageParameters={"name": udtf_name, "reason": str(e)},
        ) from None

    def build_null_checker(return_type: StructType) -> Optional[Callable[[Any], None]]:
        def raise_(result_column_index):
            raise PySparkRuntimeError(
                errorClass="UDTF_EXEC_ERROR",
                messageParameters={
                    "method_name": "eval' or 'terminate",
                    "error": f"Column {result_column_index} within a returned row had a "
                    + "value of None, either directly or within array/struct/map "
                    + "subfields, but the corresponding column type was declared as "
                    + "non-nullable; please update the UDTF to return a non-None value at "
                    + "this location or otherwise declare the column type as nullable.",
                },
            )

        def checker(data_type: DataType, result_column_index: int):
            if isinstance(data_type, ArrayType):
                element_checker = checker(data_type.elementType, result_column_index)
                contains_null = data_type.containsNull

                if element_checker is None and contains_null:
                    return None

                def check_array(arr):
                    if isinstance(arr, list):
                        for e in arr:
                            if e is None:
                                if not contains_null:
                                    raise_(result_column_index)
                            elif element_checker is not None:
                                element_checker(e)

                return check_array

            elif isinstance(data_type, MapType):
                key_checker = checker(data_type.keyType, result_column_index)
                value_checker = checker(data_type.valueType, result_column_index)
                value_contains_null = data_type.valueContainsNull

                if value_checker is None and value_contains_null:

                    def check_map(map):
                        if isinstance(map, dict):
                            for k, v in map.items():
                                if k is None:
                                    raise_(result_column_index)
                                elif key_checker is not None:
                                    key_checker(k)

                else:

                    def check_map(map):
                        if isinstance(map, dict):
                            for k, v in map.items():
                                if k is None:
                                    raise_(result_column_index)
                                elif key_checker is not None:
                                    key_checker(k)
                                if v is None:
                                    if not value_contains_null:
                                        raise_(result_column_index)
                                elif value_checker is not None:
                                    value_checker(v)

                return check_map

            elif isinstance(data_type, StructType):
                field_checkers = [checker(f.dataType, result_column_index) for f in data_type]
                nullables = [f.nullable for f in data_type]

                if all(c is None for c in field_checkers) and all(nullables):
                    return None

                def check_struct(struct):
                    if isinstance(struct, tuple):
                        for value, checker, nullable in zip(struct, field_checkers, nullables):
                            if value is None:
                                if not nullable:
                                    raise_(result_column_index)
                            elif checker is not None:
                                checker(value)

                return check_struct

            else:
                return None

        field_checkers = [
            checker(f.dataType, result_column_index=i) for i, f in enumerate(return_type)
        ]
        nullables = [f.nullable for f in return_type]

        if all(c is None for c in field_checkers) and all(nullables):
            return None

        def check(row):
            if isinstance(row, tuple):
                for i, (value, checker, nullable) in enumerate(zip(row, field_checkers, nullables)):
                    if value is None:
                        if not nullable:
                            raise_(i)
                    elif checker is not None:
                        checker(value)

        return check

    check_output_row_against_schema = build_null_checker(return_type)

    if eval_type == PythonEvalType.SQL_ARROW_TABLE_UDF and legacy_pandas_conversion:

        def wrap_arrow_udtf(f, return_type):
            import pandas as pd

            arrow_return_type = to_arrow_type(
                return_type, prefers_large_types=prefers_large_var_types
            )
            return_type_size = len(return_type)

            def verify_result(result):
                if not isinstance(result, pd.DataFrame):
                    raise PySparkTypeError(
                        errorClass="INVALID_ARROW_UDTF_RETURN_TYPE",
                        messageParameters={
                            "return_type": type(result).__name__,
                            "value": str(result),
                            "func": f.__name__,
                        },
                    )

                # Validate the output schema when the result dataframe has either output
                # rows or columns. Note that we avoid using `df.empty` here because the
                # result dataframe may contain an empty row. For example, when a UDTF is
                # defined as follows: def eval(self): yield tuple().
                if len(result) > 0 or len(result.columns) > 0:
                    if len(result.columns) != return_type_size:
                        raise PySparkRuntimeError(
                            errorClass="UDTF_RETURN_SCHEMA_MISMATCH",
                            messageParameters={
                                "expected": str(return_type_size),
                                "actual": str(len(result.columns)),
                                "func": f.__name__,
                            },
                        )

                # Verify the type and the schema of the result.
                verify_pandas_result(
                    result, return_type, assign_cols_by_name=False, truncate_return_schema=False
                )
                return result

            # Wrap the exception thrown from the UDTF in a PySparkRuntimeError.
            def func(*a: Any) -> Any:
                try:
                    return f(*a)
                except SkipRestOfInputTableException:
                    raise
                except Exception as e:
                    raise PySparkRuntimeError(
                        errorClass="UDTF_EXEC_ERROR",
                        messageParameters={"method_name": f.__name__, "error": str(e)},
                    )

            def check_return_value(res):
                # Check whether the result of an arrow UDTF is iterable before
                # using it to construct a pandas DataFrame.
                if res is not None:
                    if not isinstance(res, Iterable):
                        raise PySparkRuntimeError(
                            errorClass="UDTF_RETURN_NOT_ITERABLE",
                            messageParameters={
                                "type": type(res).__name__,
                                "func": f.__name__,
                            },
                        )
                    if check_output_row_against_schema is not None:
                        for row in res:
                            if row is not None:
                                check_output_row_against_schema(row)
                            yield row
                    else:
                        yield from res

            def evaluate(*args: pd.Series, num_rows=1):
                if len(args) == 0:
                    for _ in range(num_rows):
                        yield (
                            verify_result(pd.DataFrame(list(check_return_value(func())))),
                            arrow_return_type,
                            return_type,
                        )
                else:
                    # Create tuples from the input pandas Series, each tuple
                    # represents a row across all Series.
                    row_tuples = zip(*args)
                    for row in row_tuples:
                        yield (
                            verify_result(pd.DataFrame(list(check_return_value(func(*row))))),
                            arrow_return_type,
                            return_type,
                        )

            return evaluate

        eval_func_kwargs_support, args_kwargs_offsets = wrap_kwargs_support(
            getattr(udtf, "eval"), args_offsets, kwargs_offsets
        )
        eval = wrap_arrow_udtf(eval_func_kwargs_support, return_type)

        if hasattr(udtf, "terminate"):
            terminate = wrap_arrow_udtf(getattr(udtf, "terminate"), return_type)
        else:
            terminate = None

        cleanup = getattr(udtf, "cleanup") if hasattr(udtf, "cleanup") else None

        def mapper(_, it):
            try:
                for a in it:
                    # The eval function yields an iterator. Each element produced by this
                    # iterator is a tuple in the form of (pandas.DataFrame, arrow_return_type).
                    yield from eval(*[a[o] for o in args_kwargs_offsets], num_rows=len(a[0]))
                if terminate is not None:
                    yield from terminate()
            except SkipRestOfInputTableException:
                if terminate is not None:
                    yield from terminate()
            finally:
                if cleanup is not None:
                    cleanup()

        return mapper, None, ser, ser

    elif eval_type == PythonEvalType.SQL_ARROW_TABLE_UDF and not legacy_pandas_conversion:

        def wrap_arrow_udtf(f, return_type):
            import pyarrow as pa

            arrow_return_type = to_arrow_type(
                return_type, prefers_large_types=prefers_large_var_types
            )
            return_type_size = len(return_type)

            def verify_result(result):
                if not isinstance(result, pa.Table):
                    raise PySparkTypeError(
                        errorClass="INVALID_ARROW_UDTF_RETURN_TYPE",
                        messageParameters={
                            "return_type": type(result).__name__,
                            "value": str(result),
                            "func": f.__name__,
                        },
                    )

                # Validate the output schema when the result dataframe has either output
                # rows or columns. Note that we avoid using `df.empty` here because the
                # result dataframe may contain an empty row. For example, when a UDTF is
                # defined as follows: def eval(self): yield tuple().
                if result.num_rows > 0 or result.num_columns > 0:
                    if result.num_columns != return_type_size:
                        raise PySparkRuntimeError(
                            errorClass="UDTF_RETURN_SCHEMA_MISMATCH",
                            messageParameters={
                                "expected": str(return_type_size),
                                "actual": str(result.num_columns),
                                "func": f.__name__,
                            },
                        )

                # Verify the type and the schema of the result.
                verify_arrow_result(
                    result,
                    assign_cols_by_name=False,
                    expected_cols_and_types=[
                        (field.name, field.type) for field in arrow_return_type
                    ],
                )
                return result

            # Wrap the exception thrown from the UDTF in a PySparkRuntimeError.
            def func(*a: Any) -> Any:
                try:
                    return f(*a)
                except SkipRestOfInputTableException:
                    raise
                except Exception as e:
                    raise PySparkRuntimeError(
                        errorClass="UDTF_EXEC_ERROR",
                        messageParameters={"method_name": f.__name__, "error": str(e)},
                    )

            def check_return_value(res):
                # Check whether the result of an arrow UDTF is iterable before
                # using it to construct a pandas DataFrame.
                if res is not None:
                    if not isinstance(res, Iterable):
                        raise PySparkRuntimeError(
                            errorClass="UDTF_RETURN_NOT_ITERABLE",
                            messageParameters={
                                "type": type(res).__name__,
                                "func": f.__name__,
                            },
                        )
                    for row in res:
                        if not isinstance(row, tuple) and return_type_size == 1:
                            row = (row,)
                        if check_output_row_against_schema is not None:
                            if row is not None:
                                check_output_row_against_schema(row)
                        yield row

            def convert_to_arrow(data: Iterable):
                data = list(check_return_value(data))
                if len(data) == 0:
                    # Return one empty RecordBatch to match the left side of the lateral join
                    return [
                        pa.RecordBatch.from_pylist(data, schema=pa.schema(list(arrow_return_type)))
                    ]

                def raise_conversion_error(original_exception):
                    raise PySparkRuntimeError(
                        errorClass="UDTF_ARROW_TYPE_CONVERSION_ERROR",
                        messageParameters={
                            "data": str(data),
                            "schema": return_type.simpleString(),
                            "arrow_schema": str(arrow_return_type),
                        },
                    ) from original_exception

                try:
                    table = LocalDataToArrowConversion.convert(
                        data, return_type, prefers_large_var_types
                    )
                except PySparkValueError as e:
                    if e.getErrorClass() == "AXIS_LENGTH_MISMATCH":
                        raise PySparkRuntimeError(
                            errorClass="UDTF_RETURN_SCHEMA_MISMATCH",
                            messageParameters={
                                "expected": e.getMessageParameters()[
                                    "expected_length"
                                ],  # type: ignore[index]
                                "actual": e.getMessageParameters()[
                                    "actual_length"
                                ],  # type: ignore[index]
                                "func": f.__name__,
                            },
                        ) from e
                    # Fall through to general conversion error
                    raise_conversion_error(e)
                except Exception as e:
                    raise_conversion_error(e)

                return verify_result(table).to_batches()

            def evaluate(*args: list, num_rows=1):
                if len(args) == 0:
                    for _ in range(num_rows):
                        for batch in convert_to_arrow(func()):
                            yield batch, arrow_return_type

                else:
                    for row in zip(*args):
                        for batch in convert_to_arrow(func(*row)):
                            yield batch, arrow_return_type

            return evaluate

        eval_func_kwargs_support, args_kwargs_offsets = wrap_kwargs_support(
            getattr(udtf, "eval"), args_offsets, kwargs_offsets
        )
        eval = wrap_arrow_udtf(eval_func_kwargs_support, return_type)

        if hasattr(udtf, "terminate"):
            terminate = wrap_arrow_udtf(getattr(udtf, "terminate"), return_type)
        else:
            terminate = None

        cleanup = getattr(udtf, "cleanup") if hasattr(udtf, "cleanup") else None

        def mapper(_, it):
            try:
                converters = [
                    ArrowTableToRowsConversion._create_converter(
                        dt, none_on_identity=True, binary_as_bytes=binary_as_bytes
                    )
                    for dt in input_types
                ]
                for a in it:
                    pylist = [
                        [conv(v) for v in column.to_pylist()]
                        if conv is not None
                        else column.to_pylist()
                        for column, conv in zip(a.columns, converters)
                    ]
                    # The eval function yields an iterator. Each element produced by this
                    # iterator is a tuple in the form of (pyarrow.RecordBatch, arrow_return_type).
                    yield from eval(*[pylist[o] for o in args_kwargs_offsets], num_rows=a.num_rows)
                if terminate is not None:
                    yield from terminate()
            except SkipRestOfInputTableException:
                if terminate is not None:
                    yield from terminate()
            finally:
                if cleanup is not None:
                    cleanup()

        return mapper, None, ser, ser

    elif eval_type == PythonEvalType.SQL_ARROW_UDTF:

        def wrap_pyarrow_udtf(f, return_type):
            import pyarrow as pa

            arrow_return_type = to_arrow_type(
                return_type, prefers_large_types=use_large_var_types(runner_conf)
            )
            return_type_size = len(return_type)

            def verify_result(result):
                # Validate the output schema when the result has columns
                if result.num_columns != return_type_size:
                    raise PySparkRuntimeError(
                        errorClass="UDTF_RETURN_SCHEMA_MISMATCH",
                        messageParameters={
                            "expected": str(return_type_size),
                            "actual": str(result.num_columns),
                            "func": f.__name__,
                        },
                    )

                # We verify the type of the result and do type corerion
                # in the serializer
                return result

            # Wrap the exception thrown from the UDTF in a PySparkRuntimeError.
            def func(*a: Any) -> Any:
                try:
                    return f(*a)
                except SkipRestOfInputTableException:
                    raise
                except Exception as e:
                    raise PySparkRuntimeError(
                        errorClass="UDTF_EXEC_ERROR",
                        messageParameters={"method_name": f.__name__, "error": str(e)},
                    )

            def check_return_value(res):
                # Check whether the result of a PyArrow UDTF is iterable before processing
                if res is not None:
                    if not isinstance(res, Iterable):
                        raise PySparkRuntimeError(
                            errorClass="UDTF_RETURN_NOT_ITERABLE",
                            messageParameters={
                                "type": type(res).__name__,
                                "func": f.__name__,
                            },
                        )
                    return res
                else:
                    return iter([])

            def convert_to_arrow(data: Iterable):
                data_iter = check_return_value(data)

                # Handle PyArrow Tables/RecordBatches directly
                is_empty = True
                for item in data_iter:
                    is_empty = False
                    if isinstance(item, pa.Table):
                        yield from item.to_batches()
                    elif isinstance(item, pa.RecordBatch):
                        yield item
                    else:
                        # Arrow UDTF should only return Arrow types (RecordBatch/Table)
                        raise PySparkRuntimeError(
                            errorClass="UDTF_ARROW_TYPE_CONVERSION_ERROR",
                            messageParameters={},
                        )

                if is_empty:
                    yield pa.RecordBatch.from_pylist([], schema=pa.schema(list(arrow_return_type)))

            def evaluate(*args: pa.RecordBatch):
                # For Arrow UDTFs, unpack the RecordBatches and pass them to the function
                for batch in convert_to_arrow(func(*args)):
                    yield verify_result(batch), arrow_return_type

            return evaluate

        eval_func_kwargs_support, args_kwargs_offsets = wrap_kwargs_support(
            getattr(udtf, "eval"), args_offsets, kwargs_offsets
        )
        eval = wrap_pyarrow_udtf(eval_func_kwargs_support, return_type)

        if hasattr(udtf, "terminate"):
            terminate = wrap_pyarrow_udtf(getattr(udtf, "terminate"), return_type)
        else:
            terminate = None

        cleanup = getattr(udtf, "cleanup") if hasattr(udtf, "cleanup") else None

        def mapper(_, it):
            try:
                for a in it:
                    # For PyArrow UDTFs, pass RecordBatches directly (no row conversion needed)
                    yield from eval(*[a[o] for o in args_kwargs_offsets])
                if terminate is not None:
                    yield from terminate()
            except SkipRestOfInputTableException:
                if terminate is not None:
                    yield from terminate()
            finally:
                if cleanup is not None:
                    cleanup()

        return mapper, None, ser, ser

    else:

        def wrap_udtf(f, return_type):
            assert return_type.needConversion()
            toInternal = return_type.toInternal
            return_type_size = len(return_type)

            def verify_and_convert_result(result):
                if result is not None:
                    if hasattr(result, "__UDT__"):
                        # UDT object should not be returned directly.
                        raise PySparkRuntimeError(
                            errorClass="UDTF_INVALID_OUTPUT_ROW_TYPE",
                            messageParameters={
                                "type": type(result).__name__,
                                "func": f.__name__,
                            },
                        )

                    if hasattr(result, "__len__") and len(result) != return_type_size:
                        raise PySparkRuntimeError(
                            errorClass="UDTF_RETURN_SCHEMA_MISMATCH",
                            messageParameters={
                                "expected": str(return_type_size),
                                "actual": str(len(result)),
                                "func": f.__name__,
                            },
                        )

                    if not (isinstance(result, (list, dict, tuple)) or hasattr(result, "__dict__")):
                        raise PySparkRuntimeError(
                            errorClass="UDTF_INVALID_OUTPUT_ROW_TYPE",
                            messageParameters={
                                "type": type(result).__name__,
                                "func": f.__name__,
                            },
                        )
                    if check_output_row_against_schema is not None:
                        check_output_row_against_schema(result)
                return toInternal(result)

            # Evaluate the function and return a tuple back to the executor.
            def evaluate(*a) -> tuple:
                try:
                    res = f(*a)
                except SkipRestOfInputTableException:
                    raise
                except Exception as e:
                    raise PySparkRuntimeError(
                        errorClass="UDTF_EXEC_ERROR",
                        messageParameters={"method_name": f.__name__, "error": str(e)},
                    )

                if res is None:
                    # If the function returns None or does not have an explicit return statement,
                    # an empty tuple is returned to the executor.
                    # This is because directly constructing tuple(None) results in an exception.
                    return tuple()

                if not isinstance(res, Iterable):
                    raise PySparkRuntimeError(
                        errorClass="UDTF_RETURN_NOT_ITERABLE",
                        messageParameters={
                            "type": type(res).__name__,
                            "func": f.__name__,
                        },
                    )

                # If the function returns a result, we map it to the internal representation and
                # returns the results as a tuple.
                return tuple(map(verify_and_convert_result, res))

            return evaluate

        eval_func_kwargs_support, args_kwargs_offsets = wrap_kwargs_support(
            getattr(udtf, "eval"), args_offsets, kwargs_offsets
        )
        eval = wrap_udtf(eval_func_kwargs_support, return_type)

        if hasattr(udtf, "terminate"):
            terminate = wrap_udtf(getattr(udtf, "terminate"), return_type)
        else:
            terminate = None

        cleanup = getattr(udtf, "cleanup") if hasattr(udtf, "cleanup") else None

        # Return an iterator of iterators.
        def mapper(_, it):
            try:
                for a in it:
                    yield eval(*[a[o] for o in args_kwargs_offsets])
                if terminate is not None:
                    yield terminate()
            except SkipRestOfInputTableException:
                if terminate is not None:
                    yield terminate()
            finally:
                if cleanup is not None:
                    cleanup()

        return mapper, None, ser, ser


def read_udfs(pickleSer, infile, eval_type):
    runner_conf = {}

    state_server_port = None
    key_schema = None
    if eval_type in (
        PythonEvalType.SQL_ARROW_BATCHED_UDF,
        PythonEvalType.SQL_SCALAR_PANDAS_UDF,
        PythonEvalType.SQL_SCALAR_ARROW_UDF,
        PythonEvalType.SQL_COGROUPED_MAP_PANDAS_UDF,
        PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF,
        PythonEvalType.SQL_SCALAR_ARROW_ITER_UDF,
        PythonEvalType.SQL_MAP_PANDAS_ITER_UDF,
        PythonEvalType.SQL_MAP_ARROW_ITER_UDF,
        PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF,
        PythonEvalType.SQL_GROUPED_MAP_PANDAS_ITER_UDF,
        PythonEvalType.SQL_GROUPED_AGG_PANDAS_UDF,
        PythonEvalType.SQL_GROUPED_AGG_ARROW_UDF,
        PythonEvalType.SQL_WINDOW_AGG_PANDAS_UDF,
        PythonEvalType.SQL_WINDOW_AGG_ARROW_UDF,
        PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE,
        PythonEvalType.SQL_GROUPED_MAP_ARROW_UDF,
        PythonEvalType.SQL_GROUPED_MAP_ARROW_ITER_UDF,
        PythonEvalType.SQL_COGROUPED_MAP_ARROW_UDF,
        PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_UDF,
        PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_INIT_STATE_UDF,
        PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_UDF,
        PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_INIT_STATE_UDF,
    ):
        # Load conf used for pandas_udf evaluation
        num_conf = read_int(infile)
        for i in range(num_conf):
            k = utf8_deserializer.loads(infile)
            v = utf8_deserializer.loads(infile)
            runner_conf[k] = v

        state_object_schema = None
        if eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE:
            state_object_schema = StructType.fromJson(json.loads(utf8_deserializer.loads(infile)))
        elif (
            eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_UDF
            or eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_INIT_STATE_UDF
            or eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_UDF
            or eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_INIT_STATE_UDF
        ):
            state_server_port = read_int(infile)
            if state_server_port == -1:
                state_server_port = utf8_deserializer.loads(infile)
            key_schema = StructType.fromJson(json.loads(utf8_deserializer.loads(infile)))

        # NOTE: if timezone is set here, that implies respectSessionTimeZone is True
        timezone = runner_conf.get("spark.sql.session.timeZone", None)
        prefers_large_var_types = use_large_var_types(runner_conf)
        safecheck = (
            runner_conf.get("spark.sql.execution.pandas.convertToArrowArraySafely", "false").lower()
            == "true"
        )
        int_to_decimal_coercion_enabled = (
            runner_conf.get(
                "spark.sql.execution.pythonUDF.pandas.intToDecimalCoercionEnabled", "false"
            ).lower()
            == "true"
        )
        binary_as_bytes = (
            runner_conf.get("spark.sql.execution.pyspark.binaryAsBytes", "true").lower() == "true"
        )
        _assign_cols_by_name = assign_cols_by_name(runner_conf)

        if (
            eval_type == PythonEvalType.SQL_GROUPED_MAP_ARROW_UDF
            or eval_type == PythonEvalType.SQL_GROUPED_MAP_ARROW_ITER_UDF
        ):
            ser = GroupArrowUDFSerializer(_assign_cols_by_name)
        elif eval_type in (
            PythonEvalType.SQL_GROUPED_AGG_ARROW_UDF,
            PythonEvalType.SQL_WINDOW_AGG_ARROW_UDF,
        ):
            ser = ArrowStreamAggArrowUDFSerializer(timezone, True, _assign_cols_by_name, True)
        elif eval_type in (
            PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF,
            PythonEvalType.SQL_GROUPED_AGG_PANDAS_UDF,
            PythonEvalType.SQL_WINDOW_AGG_PANDAS_UDF,
        ):
            ser = GroupPandasUDFSerializer(
                timezone, safecheck, _assign_cols_by_name, int_to_decimal_coercion_enabled
            )
        elif eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_ITER_UDF:
            ser = GroupPandasIterUDFSerializer(
                timezone, safecheck, _assign_cols_by_name, int_to_decimal_coercion_enabled
            )
        elif eval_type == PythonEvalType.SQL_COGROUPED_MAP_ARROW_UDF:
            ser = CogroupArrowUDFSerializer(_assign_cols_by_name)
        elif eval_type == PythonEvalType.SQL_COGROUPED_MAP_PANDAS_UDF:
            ser = CogroupPandasUDFSerializer(
                timezone,
                safecheck,
                _assign_cols_by_name,
                int_to_decimal_coercion_enabled=int_to_decimal_coercion_enabled,
                arrow_cast=True,
            )
        elif eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE:
            arrow_max_records_per_batch = runner_conf.get(
                "spark.sql.execution.arrow.maxRecordsPerBatch", 10000
            )
            arrow_max_records_per_batch = int(arrow_max_records_per_batch)

            ser = ApplyInPandasWithStateSerializer(
                timezone,
                safecheck,
                _assign_cols_by_name,
                state_object_schema,
                arrow_max_records_per_batch,
                prefers_large_var_types,
                int_to_decimal_coercion_enabled=int_to_decimal_coercion_enabled,
            )
        elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_UDF:
            arrow_max_records_per_batch = runner_conf.get(
                "spark.sql.execution.arrow.maxRecordsPerBatch", 10000
            )
            arrow_max_records_per_batch = int(arrow_max_records_per_batch)

            arrow_max_bytes_per_batch = runner_conf.get(
                "spark.sql.execution.arrow.maxBytesPerBatch", 2**31 - 1
            )
            arrow_max_bytes_per_batch = int(arrow_max_bytes_per_batch)

            ser = TransformWithStateInPandasSerializer(
                timezone,
                safecheck,
                _assign_cols_by_name,
                arrow_max_records_per_batch,
                arrow_max_bytes_per_batch,
                int_to_decimal_coercion_enabled=int_to_decimal_coercion_enabled,
            )
        elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_INIT_STATE_UDF:
            arrow_max_records_per_batch = runner_conf.get(
                "spark.sql.execution.arrow.maxRecordsPerBatch", 10000
            )
            arrow_max_records_per_batch = int(arrow_max_records_per_batch)

            arrow_max_bytes_per_batch = runner_conf.get(
                "spark.sql.execution.arrow.maxBytesPerBatch", 2**31 - 1
            )
            arrow_max_bytes_per_batch = int(arrow_max_bytes_per_batch)

            ser = TransformWithStateInPandasInitStateSerializer(
                timezone,
                safecheck,
                _assign_cols_by_name,
                arrow_max_records_per_batch,
                arrow_max_bytes_per_batch,
                int_to_decimal_coercion_enabled=int_to_decimal_coercion_enabled,
            )
        elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_UDF:
            arrow_max_records_per_batch = runner_conf.get(
                "spark.sql.execution.arrow.maxRecordsPerBatch", 10000
            )
            arrow_max_records_per_batch = int(arrow_max_records_per_batch)

            ser = TransformWithStateInPySparkRowSerializer(arrow_max_records_per_batch)
        elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_INIT_STATE_UDF:
            arrow_max_records_per_batch = runner_conf.get(
                "spark.sql.execution.arrow.maxRecordsPerBatch", 10000
            )
            arrow_max_records_per_batch = int(arrow_max_records_per_batch)

            ser = TransformWithStateInPySparkRowInitStateSerializer(arrow_max_records_per_batch)
        elif eval_type == PythonEvalType.SQL_MAP_ARROW_ITER_UDF:
            ser = ArrowStreamUDFSerializer()
        elif eval_type in (
            PythonEvalType.SQL_SCALAR_ARROW_UDF,
            PythonEvalType.SQL_SCALAR_ARROW_ITER_UDF,
        ):
            # Arrow cast and safe check are always enabled
            ser = ArrowStreamArrowUDFSerializer(timezone, True, _assign_cols_by_name, True)
        elif (
            eval_type == PythonEvalType.SQL_ARROW_BATCHED_UDF
            and not use_legacy_pandas_udf_conversion(runner_conf)
        ):
            input_types = [
                f.dataType for f in _parse_datatype_json_string(utf8_deserializer.loads(infile))
            ]
            ser = ArrowBatchUDFSerializer(
                timezone, safecheck, input_types, int_to_decimal_coercion_enabled, binary_as_bytes
            )
        else:
            # Scalar Pandas UDF handles struct type arguments as pandas DataFrames instead of
            # pandas Series. See SPARK-27240.
            df_for_struct = (
                eval_type == PythonEvalType.SQL_SCALAR_PANDAS_UDF
                or eval_type == PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF
                or eval_type == PythonEvalType.SQL_MAP_PANDAS_ITER_UDF
            )
            # Arrow-optimized Python UDF takes a struct type argument as a Row
            struct_in_pandas = (
                "row" if eval_type == PythonEvalType.SQL_ARROW_BATCHED_UDF else "dict"
            )
            ndarray_as_list = eval_type == PythonEvalType.SQL_ARROW_BATCHED_UDF
            # Arrow-optimized Python UDF takes input types
            input_types = (
                [f.dataType for f in _parse_datatype_json_string(utf8_deserializer.loads(infile))]
                if eval_type == PythonEvalType.SQL_ARROW_BATCHED_UDF
                else None
            )

            ser = ArrowStreamPandasUDFSerializer(
                timezone,
                safecheck,
                _assign_cols_by_name,
                df_for_struct,
                struct_in_pandas,
                ndarray_as_list,
                True,
                input_types,
                int_to_decimal_coercion_enabled=int_to_decimal_coercion_enabled,
            )
    else:
        batch_size = int(os.environ.get("PYTHON_UDF_BATCH_SIZE", "100"))
        ser = BatchedSerializer(CPickleSerializer(), batch_size)

    is_profiling = read_bool(infile)
    if is_profiling:
        profiler = utf8_deserializer.loads(infile)
    else:
        profiler = None

    num_udfs = read_int(infile)

    is_scalar_iter = eval_type in (
        PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF,
        PythonEvalType.SQL_SCALAR_ARROW_ITER_UDF,
    )
    is_map_pandas_iter = eval_type == PythonEvalType.SQL_MAP_PANDAS_ITER_UDF
    is_map_arrow_iter = eval_type == PythonEvalType.SQL_MAP_ARROW_ITER_UDF

    if is_scalar_iter or is_map_pandas_iter or is_map_arrow_iter:
        # TODO: Better error message for num_udfs != 1
        if is_scalar_iter:
            assert num_udfs == 1, "One SCALAR_ITER UDF expected here."
        if is_map_pandas_iter:
            assert num_udfs == 1, "One MAP_PANDAS_ITER UDF expected here."
        if is_map_arrow_iter:
            assert num_udfs == 1, "One MAP_ARROW_ITER UDF expected here."

        arg_offsets, udf = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )

        def func(_, iterator):
            num_input_rows = 0

            def map_batch(batch):
                nonlocal num_input_rows

                udf_args = [batch[offset] for offset in arg_offsets]
                num_input_rows += len(udf_args[0])
                if len(udf_args) == 1:
                    return udf_args[0]
                else:
                    return tuple(udf_args)

            iterator = map(map_batch, iterator)
            result_iter = udf(iterator)

            num_output_rows = 0
            for result_batch, result_type in result_iter:
                num_output_rows += len(result_batch)
                # This check is for Scalar Iterator UDF to fail fast.
                # The length of the entire input can only be explicitly known
                # by consuming the input iterator in user side. Therefore,
                # it's very unlikely the output length is higher than
                # input length.
                if is_scalar_iter and num_output_rows > num_input_rows:
                    raise PySparkRuntimeError(
                        errorClass="PANDAS_UDF_OUTPUT_EXCEEDS_INPUT_ROWS", messageParameters={}
                    )
                yield (result_batch, result_type)

            if is_scalar_iter:
                try:
                    next(iterator)
                except StopIteration:
                    pass
                else:
                    raise PySparkRuntimeError(
                        errorClass="STOP_ITERATION_OCCURRED_FROM_SCALAR_ITER_PANDAS_UDF",
                        messageParameters={},
                    )

                if num_output_rows != num_input_rows:
                    raise PySparkRuntimeError(
                        errorClass="RESULT_LENGTH_MISMATCH_FOR_SCALAR_ITER_PANDAS_UDF",
                        messageParameters={
                            "output_length": str(num_output_rows),
                            "input_length": str(num_input_rows),
                        },
                    )

        # profiling is not supported for UDF
        return func, None, ser, ser

    def extract_key_value_indexes(grouped_arg_offsets):
        """
        Helper function to extract the key and value indexes from arg_offsets for the grouped and
        cogrouped pandas udfs. See BasePandasGroupExec.resolveArgOffsets for equivalent scala code.

        Parameters
        ----------
        grouped_arg_offsets:  list
            List containing the key and value indexes of columns of the
            DataFrames to be passed to the udf. It consists of n repeating groups where n is the
            number of DataFrames.  Each group has the following format:
                group[0]: length of group
                group[1]: length of key indexes
                group[2.. group[1] +2]: key attributes
                group[group[1] +3 group[0]]: value attributes
        """
        parsed = []
        idx = 0
        while idx < len(grouped_arg_offsets):
            offsets_len = grouped_arg_offsets[idx]
            idx += 1
            offsets = grouped_arg_offsets[idx : idx + offsets_len]
            split_index = offsets[0] + 1
            offset_keys = offsets[1:split_index]
            offset_values = offsets[split_index:]
            parsed.append([offset_keys, offset_values])
            idx += offsets_len
        return parsed

    if eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF:
        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See FlatMapGroupsInPandasExec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        parsed_offsets = extract_key_value_indexes(arg_offsets)

        # Create function like this:
        #   mapper a: f([a[0]], [a[0], a[1]])
        def mapper(a):
            keys = [a[o] for o in parsed_offsets[0][0]]
            vals = [a[o] for o in parsed_offsets[0][1]]
            return f(keys, vals)

    elif eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_ITER_UDF:
        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See FlatMapGroupsInPandasExec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        parsed_offsets = extract_key_value_indexes(arg_offsets)

        # Create mapper similar to Arrow iterator:
        # `a` is an iterator of Series lists (one list per batch, containing all columns)
        # Materialize first batch to get keys, then create generator for value batches
        def mapper(a):
            import itertools

            series_iter = iter(a)
            # Need to materialize the first series list to get the keys
            first_series_list = next(series_iter)

            keys = [first_series_list[o] for o in parsed_offsets[0][0]]
            value_series_gen = (
                [series_list[o] for o in parsed_offsets[0][1]]
                for series_list in itertools.chain((first_series_list,), series_iter)
            )

            return f(keys, value_series_gen)

    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_UDF:
        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See TransformWithStateInPandasExec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        parsed_offsets = extract_key_value_indexes(arg_offsets)
        ser.key_offsets = parsed_offsets[0][0]
        stateful_processor_api_client = StatefulProcessorApiClient(state_server_port, key_schema)

        def mapper(a):
            mode = a[0]

            if mode == TransformWithStateInPandasFuncMode.PROCESS_DATA:
                key = a[1]

                def values_gen():
                    for x in a[2]:
                        retVal = x[1].iloc[:, parsed_offsets[0][1]]
                        yield retVal

                # This must be generator comprehension - do not materialize.
                return f(stateful_processor_api_client, mode, key, values_gen())
            else:
                # mode == PROCESS_TIMER or mode == COMPLETE
                return f(stateful_processor_api_client, mode, None, iter([]))

    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PANDAS_INIT_STATE_UDF:
        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See TransformWithStateInPandasExec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        # parsed offsets:
        # [
        #     [groupingKeyOffsets, dedupDataOffsets],
        #     [initStateGroupingOffsets, dedupInitDataOffsets]
        # ]
        parsed_offsets = extract_key_value_indexes(arg_offsets)
        ser.key_offsets = parsed_offsets[0][0]
        ser.init_key_offsets = parsed_offsets[1][0]
        stateful_processor_api_client = StatefulProcessorApiClient(state_server_port, key_schema)

        def mapper(a):
            mode = a[0]

            if mode == TransformWithStateInPandasFuncMode.PROCESS_DATA:
                key = a[1]

                def values_gen():
                    for x in a[2]:
                        retVal = [x[1][o] for o in parsed_offsets[0][1]]
                        initVal = [x[2][o] for o in parsed_offsets[1][1]]
                        yield retVal, initVal

                # This must be generator comprehension - do not materialize.
                return f(stateful_processor_api_client, mode, key, values_gen())
            else:
                # mode == PROCESS_TIMER or mode == COMPLETE
                return f(stateful_processor_api_client, mode, None, iter([]))

    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_UDF:
        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See TransformWithStateInPySparkExec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        parsed_offsets = extract_key_value_indexes(arg_offsets)
        ser.key_offsets = parsed_offsets[0][0]
        stateful_processor_api_client = StatefulProcessorApiClient(state_server_port, key_schema)

        def mapper(a):
            mode = a[0]

            if mode == TransformWithStateInPandasFuncMode.PROCESS_DATA:
                key = a[1]
                values = a[2]

                # This must be generator comprehension - do not materialize.
                return f(stateful_processor_api_client, mode, key, values)
            else:
                # mode == PROCESS_TIMER or mode == COMPLETE
                return f(stateful_processor_api_client, mode, None, iter([]))

    elif eval_type == PythonEvalType.SQL_TRANSFORM_WITH_STATE_PYTHON_ROW_INIT_STATE_UDF:
        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See TransformWithStateInPandasExec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        # parsed offsets:
        # [
        #     [groupingKeyOffsets, dedupDataOffsets],
        #     [initStateGroupingOffsets, dedupInitDataOffsets]
        # ]
        parsed_offsets = extract_key_value_indexes(arg_offsets)
        ser.key_offsets = parsed_offsets[0][0]
        ser.init_key_offsets = parsed_offsets[1][0]
        stateful_processor_api_client = StatefulProcessorApiClient(state_server_port, key_schema)

        def mapper(a):
            mode = a[0]

            if mode == TransformWithStateInPandasFuncMode.PROCESS_DATA:
                key = a[1]
                values = a[2]

                # This must be generator comprehension - do not materialize.
                return f(stateful_processor_api_client, mode, key, values)
            else:
                # mode == PROCESS_TIMER or mode == COMPLETE
                return f(stateful_processor_api_client, mode, None, iter([]))

    elif (
        eval_type == PythonEvalType.SQL_GROUPED_MAP_ARROW_UDF
        or eval_type == PythonEvalType.SQL_GROUPED_MAP_ARROW_ITER_UDF
    ):
        import pyarrow as pa

        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See FlatMapGroupsInPandasExec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        parsed_offsets = extract_key_value_indexes(arg_offsets)

        def batch_from_offset(batch, offsets):
            return pa.RecordBatch.from_arrays(
                arrays=[batch.columns[o] for o in offsets],
                names=[batch.schema.names[o] for o in offsets],
            )

        def mapper(a):
            batch_iter = iter(a)
            # Need to materialize the first batch to get the keys
            first_batch = next(batch_iter)

            keys = batch_from_offset(first_batch, parsed_offsets[0][0])
            value_batches = (
                batch_from_offset(b, parsed_offsets[0][1])
                for b in itertools.chain((first_batch,), batch_iter)
            )

            return f(keys, value_batches)

    elif eval_type == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF_WITH_STATE:
        # We assume there is only one UDF here because grouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1

        # See FlatMapGroupsInPandas(WithState)Exec for how arg_offsets are used to
        # distinguish between grouping attributes and data attributes
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )
        parsed_offsets = extract_key_value_indexes(arg_offsets)

        def mapper(a):
            """
            The function receives (iterator of data, state) and performs extraction of key and
            value from the data, with retaining lazy evaluation.

            See `load_stream` in `ApplyInPandasWithStateSerializer` for more details on the input
            and see `wrap_grouped_map_pandas_udf_with_state` for more details on how output will
            be used.
            """
            from itertools import tee

            state = a[1]
            data_gen = (x[0] for x in a[0])

            # We know there should be at least one item in the iterator/generator.
            # We want to peek the first element to construct the key, hence applying
            # tee to construct the key while we retain another iterator/generator
            # for values.
            keys_gen, values_gen = tee(data_gen)
            keys_elem = next(keys_gen)
            keys = [keys_elem[o] for o in parsed_offsets[0][0]]

            # This must be generator comprehension - do not materialize.
            vals = ([x[o] for o in parsed_offsets[0][1]] for x in values_gen)

            return f(keys, vals, state)

    elif eval_type == PythonEvalType.SQL_COGROUPED_MAP_PANDAS_UDF:
        # We assume there is only one UDF here because cogrouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )

        parsed_offsets = extract_key_value_indexes(arg_offsets)

        def mapper(a):
            df1_keys = [a[0][o] for o in parsed_offsets[0][0]]
            df1_vals = [a[0][o] for o in parsed_offsets[0][1]]
            df2_keys = [a[1][o] for o in parsed_offsets[1][0]]
            df2_vals = [a[1][o] for o in parsed_offsets[1][1]]
            return f(df1_keys, df1_vals, df2_keys, df2_vals)

    elif eval_type == PythonEvalType.SQL_COGROUPED_MAP_ARROW_UDF:
        import pyarrow as pa

        # We assume there is only one UDF here because cogrouped map doesn't
        # support combining multiple UDFs.
        assert num_udfs == 1
        arg_offsets, f = read_single_udf(
            pickleSer, infile, eval_type, runner_conf, udf_index=0, profiler=profiler
        )

        parsed_offsets = extract_key_value_indexes(arg_offsets)

        def batch_from_offset(batch, offsets):
            return pa.RecordBatch.from_arrays(
                arrays=[batch.columns[o] for o in offsets],
                names=[batch.schema.names[o] for o in offsets],
            )

        def table_from_batches(batches, offsets):
            return pa.Table.from_batches([batch_from_offset(batch, offsets) for batch in batches])

        def mapper(a):
            df1_keys = table_from_batches(a[0], parsed_offsets[0][0])
            df1_vals = table_from_batches(a[0], parsed_offsets[0][1])
            df2_keys = table_from_batches(a[1], parsed_offsets[1][0])
            df2_vals = table_from_batches(a[1], parsed_offsets[1][1])
            return f(df1_keys, df1_vals, df2_keys, df2_vals)

    else:
        udfs = []
        for i in range(num_udfs):
            udfs.append(
                read_single_udf(
                    pickleSer, infile, eval_type, runner_conf, udf_index=i, profiler=profiler
                )
            )

        def mapper(a):
            result = tuple(f(*[a[o] for o in arg_offsets]) for arg_offsets, f in udfs)
            # In the special case of a single UDF this will return a single result rather
            # than a tuple of results; this is the format that the JVM side expects.
            if len(result) == 1:
                return result[0]
            else:
                return result

    def func(_, it):
        return map(mapper, it)

    # profiling is not supported for UDF
    return func, None, ser, ser


@with_faulthandler
def main(infile, outfile):
    try:
        boot_time = time.time()
        split_index = read_int(infile)
        if split_index == -1:  # for unit tests
            sys.exit(-1)
        start_faulthandler_periodic_traceback()
        check_python_version(infile)

        # read inputs only for a barrier task
        isBarrier = read_bool(infile)

        memory_limit_mb = int(os.environ.get("PYSPARK_EXECUTOR_MEMORY_MB", "-1"))
        setup_memory_limits(memory_limit_mb)

        # initialize global state
        taskContext = None
        if isBarrier:
            boundPort = read_int(infile)
            secret = None
            if boundPort == -1:
                boundPort = utf8_deserializer.loads(infile)
            else:
                secret = utf8_deserializer.loads(infile)
            taskContext = BarrierTaskContext._getOrCreate()
            BarrierTaskContext._initialize(boundPort, secret)
            # Set the task context instance here, so we can get it by TaskContext.get for
            # both TaskContext and BarrierTaskContext
            TaskContext._setTaskContext(taskContext)
        else:
            taskContext = TaskContext._getOrCreate()
        # read inputs for TaskContext info
        taskContext._stageId = read_int(infile)
        taskContext._partitionId = read_int(infile)
        taskContext._attemptNumber = read_int(infile)
        taskContext._taskAttemptId = read_long(infile)
        taskContext._cpus = read_int(infile)
        taskContext._resources = {}
        for r in range(read_int(infile)):
            key = utf8_deserializer.loads(infile)
            name = utf8_deserializer.loads(infile)
            addresses = []
            taskContext._resources = {}
            for a in range(read_int(infile)):
                addresses.append(utf8_deserializer.loads(infile))
            taskContext._resources[key] = ResourceInformation(name, addresses)

        taskContext._localProperties = dict()
        for i in range(read_int(infile)):
            k = utf8_deserializer.loads(infile)
            v = utf8_deserializer.loads(infile)
            taskContext._localProperties[k] = v

        shuffle.MemoryBytesSpilled = 0
        shuffle.DiskBytesSpilled = 0
        _accumulatorRegistry.clear()

        setup_spark_files(infile)
        setup_broadcasts(infile)

        _accumulatorRegistry.clear()
        eval_type = read_int(infile)
        if eval_type == PythonEvalType.NON_UDF:
            func, profiler, deserializer, serializer = read_command(pickleSer, infile)
        elif eval_type in (
            PythonEvalType.SQL_TABLE_UDF,
            PythonEvalType.SQL_ARROW_TABLE_UDF,
            PythonEvalType.SQL_ARROW_UDTF,
        ):
            func, profiler, deserializer, serializer = read_udtf(pickleSer, infile, eval_type)
        else:
            func, profiler, deserializer, serializer = read_udfs(pickleSer, infile, eval_type)

        init_time = time.time()

        def process():
            iterator = deserializer.load_stream(infile)
            out_iter = func(split_index, iterator)
            try:
                serializer.dump_stream(out_iter, outfile)
            finally:
                if hasattr(out_iter, "close"):
                    out_iter.close()

        with capture_outputs():
            if profiler:
                profiler.profile(process)
            else:
                process()

        # Reset task context to None. This is a guard code to avoid residual context when worker
        # reuse.
        TaskContext._setTaskContext(None)
        BarrierTaskContext._setTaskContext(None)
    except BaseException as e:
        handle_worker_exception(e, outfile)
        sys.exit(-1)
    finish_time = time.time()
    report_times(outfile, boot_time, init_time, finish_time)
    write_long(shuffle.MemoryBytesSpilled, outfile)
    write_long(shuffle.DiskBytesSpilled, outfile)

    # Mark the beginning of the accumulators section of the output
    write_int(SpecialLengths.END_OF_DATA_SECTION, outfile)
    send_accumulator_updates(outfile)

    # check end of stream
    if read_int(infile) == SpecialLengths.END_OF_STREAM:
        write_int(SpecialLengths.END_OF_STREAM, outfile)
    else:
        # write a different value to tell JVM to not reuse this worker
        write_int(SpecialLengths.END_OF_DATA_SECTION, outfile)
        sys.exit(-1)


if __name__ == "__main__":
    # Read information about how to connect back to the JVM from the environment.
    conn_info = os.environ.get(
        "PYTHON_WORKER_FACTORY_SOCK_PATH", int(os.environ.get("PYTHON_WORKER_FACTORY_PORT", -1))
    )
    auth_secret = os.environ.get("PYTHON_WORKER_FACTORY_SECRET")
    (sock_file, _) = local_connect_and_auth(conn_info, auth_secret)
    # TODO: Remove the following two lines and use `Process.pid()` when we drop JDK 8.
    write_int(os.getpid(), sock_file)
    sock_file.flush()
    main(sock_file, sock_file)
