# Pydantic Type System - Comprehensive Analysis & Satya Comparison

## Document Purpose

This document provides a comprehensive analysis of ALL types supported by Pydantic (v2.x) and compares them with Satya's current implementation to identify gaps and opportunities for enhancement.

**Generated**: 2025-10-09  
**Source**: DeepWiki analysis of pydantic/pydantic repository  
**Satya Version**: 0.3.86  

---

## Table of Contents

1. [String Types](#string-types)
2. [Numeric Types](#numeric-types)
3. [Date/Time Types](#datetime-types)
4. [Network Types](#network-types)
5. [File Types](#file-types)
6. [Collection Types](#collection-types)
7. [Special Types](#special-types)
8. [Constrained Types](#constrained-types)
9. [Advanced Type Features](#advanced-type-features)
10. [Pydantic-Extra-Types](#pydantic-extra-types)
11. [Gap Analysis](#gap-analysis)
12. [Recommendations](#recommendations)

---

## 1. String Types

### Pydantic Support

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `str` | Standard string | ✅ Full | Native support |
| `bytes` | Byte string | ✅ Full | Native support |
| `StrictStr` | Strict mode string | ⚠️ Partial | Can implement with Field(strict=True) |
| `StrictBytes` | Strict mode bytes | ⚠️ Partial | Can implement with Field(strict=True) |
| `SecretStr` | Concealed string in repr | ❌ Missing | Security feature |
| `SecretBytes` | Concealed bytes in repr | ❌ Missing | Security feature |
| `ImportString` | Importable Python object | ❌ Missing | Advanced feature |

**Constrained String Parameters** (via `constr` or `Field`):
- `min_length` - ✅ Supported in Satya
- `max_length` - ✅ Supported in Satya
- `pattern` - ✅ Supported in Satya
- `strip_whitespace` - ⚠️ Partial (done in validation)
- `to_upper` - ❌ Missing
- `to_lower` - ❌ Missing
- `strict` - ⚠️ Partial

---

## 2. Numeric Types

### Integer Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `int` | Standard integer | ✅ Full | Native support |
| `StrictInt` | Strict mode integer | ⚠️ Partial | Can implement |
| `PositiveInt` | int > 0 | ✅ Full | Via Field(gt=0) |
| `NegativeInt` | int < 0 | ✅ Full | Via Field(lt=0) |
| `NonNegativeInt` | int >= 0 | ✅ Full | Via Field(ge=0) |
| `NonPositiveInt` | int <= 0 | ✅ Full | Via Field(le=0) |

**Constrained Integer Parameters** (via `conint` or `Field`):
- `gt` (greater than) - ✅ Supported
- `ge` (greater than or equal) - ✅ Supported
- `lt` (less than) - ✅ Supported
- `le` (less than or equal) - ✅ Supported
- `multiple_of` - ❌ Missing
- `strict` - ⚠️ Partial

### Float Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `float` | Standard float | ✅ Full | Native support |
| `StrictFloat` | Strict mode float | ⚠️ Partial | Can implement |
| `PositiveFloat` | float > 0 | ✅ Full | Via Field(gt=0) |
| `NegativeFloat` | float < 0 | ✅ Full | Via Field(lt=0) |
| `NonNegativeFloat` | float >= 0 | ✅ Full | Via Field(ge=0) |
| `NonPositiveFloat` | float <= 0 | ✅ Full | Via Field(le=0) |
| `FiniteFloat` | No inf/-inf/nan | ❌ Missing | Validation feature |
| `AllowInfNan` | Allow inf/nan | ❌ Missing | Validation feature |

**Constrained Float Parameters** (via `confloat` or `Field`):
- `gt`, `ge`, `lt`, `le` - ✅ Supported
- `multiple_of` - ❌ Missing
- `allow_inf_nan` - ❌ Missing
- `strict` - ⚠️ Partial

### Other Numeric Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `complex` | Complex numbers | ❌ Missing | Python builtin |
| `Decimal` | Decimal numbers | ✅ Full | Supported |
| `ByteSize` | Size in bytes | ❌ Missing | Utility type |

**Constrained Decimal Parameters** (via `condecimal`):
- `gt`, `ge`, `lt`, `le` - ✅ Supported
- `multiple_of` - ❌ Missing
- `max_digits` - ❌ Missing
- `decimal_places` - ❌ Missing
- `allow_inf_nan` - ❌ Missing

---

## 3. Date/Time Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `date` | Date object | ✅ Full | Python datetime.date |
| `datetime` | Datetime object | ✅ Full | Python datetime.datetime |
| `time` | Time object | ⚠️ Partial | Python datetime.time |
| `timedelta` | Time duration | ⚠️ Partial | Python datetime.timedelta |
| `PastDate` | Date in the past | ❌ Missing | Validation constraint |
| `FutureDate` | Date in the future | ❌ Missing | Validation constraint |
| `PastDatetime` | Datetime in the past | ❌ Missing | Validation constraint |
| `FutureDatetime` | Datetime in the future | ❌ Missing | Validation constraint |
| `AwareDatetime` | Timezone-aware datetime | ❌ Missing | Validation constraint |
| `NaiveDatetime` | Timezone-naive datetime | ❌ Missing | Validation constraint |

**Constrained Date Parameters** (via `condate`):
- `gt`, `ge`, `lt`, `le` - ❌ Missing
- `strict` - ⚠️ Partial

---

## 4. Network Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `AnyUrl` | Any URL | ⚠️ Partial | Basic URL validation |
| `AnyHttpUrl` | HTTP/HTTPS URL | ⚠️ Partial | Basic URL validation |
| `FileUrl` | File URL | ❌ Missing | Specific URL type |
| `HttpUrl` | HTTP URL | ⚠️ Partial | Basic URL validation |
| `FtpUrl` | FTP URL | ❌ Missing | Specific URL type |
| `WebsocketUrl` | WebSocket URL | ❌ Missing | Specific URL type |
| `AnyWebsocketUrl` | Any WebSocket URL | ❌ Missing | Specific URL type |
| `EmailStr` | Email address | ✅ Full | Via Field(email=True) |
| `NameEmail` | Name + Email | ❌ Missing | Composite type |
| `IPvAnyAddress` | Any IP address | ❌ Missing | Network type |
| `IPvAnyInterface` | Any IP interface | ❌ Missing | Network type |
| `IPvAnyNetwork` | Any IP network | ❌ Missing | Network type |
| `PostgresDsn` | PostgreSQL DSN | ❌ Missing | Database URL |
| `CockroachDsn` | CockroachDB DSN | ❌ Missing | Database URL |
| `AmqpDsn` | AMQP DSN | ❌ Missing | Message queue URL |
| `RedisDsn` | Redis DSN | ❌ Missing | Database URL |
| `MongoDsn` | MongoDB DSN | ❌ Missing | Database URL |
| `KafkaDsn` | Kafka DSN | ❌ Missing | Message queue URL |
| `NatsDsn` | NATS DSN | ❌ Missing | Message queue URL |
| `MySQLDsn` | MySQL DSN | ❌ Missing | Database URL |
| `MariaDBDsn` | MariaDB DSN | ❌ Missing | Database URL |
| `ClickHouseDsn` | ClickHouse DSN | ❌ Missing | Database URL |
| `SnowflakeDsn` | Snowflake DSN | ❌ Missing | Database URL |

---

## 5. File Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `FilePath` | Existing file path | ❌ Missing | Filesystem validation |
| `DirectoryPath` | Existing directory path | ❌ Missing | Filesystem validation |
| `NewPath` | Non-existing path | ❌ Missing | Filesystem validation |
| `SocketPath` | Unix socket path | ❌ Missing | Filesystem validation |

---

## 6. Collection Types

### List Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `list` | Standard list | ✅ Full | Native support |
| `List[T]` | Typed list | ✅ Full | Generic support |
| `Sequence[T]` | Sequence protocol | ⚠️ Partial | Can validate as list |
| `MutableSequence[T]` | Mutable sequence | ⚠️ Partial | Can validate as list |

**Constrained List Parameters** (via `conlist`):
- `item_type` - ✅ Supported (via List[T])
- `min_length` / `min_items` - ✅ Supported
- `max_length` / `max_items` - ✅ Supported
- `unique_items` - ✅ Supported

### Tuple Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `tuple` | Standard tuple | ⚠️ Partial | Basic support |
| `Tuple[T, ...]` | Homogeneous tuple | ⚠️ Partial | Generic support |
| `Tuple[T1, T2, ...]` | Heterogeneous tuple | ⚠️ Partial | Fixed-length tuple |
| `NamedTuple` | Named tuple | ❌ Missing | Structured tuple |

### Set Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `set` | Standard set | ⚠️ Partial | Basic support |
| `Set[T]` | Typed set | ⚠️ Partial | Generic support |
| `frozenset` | Immutable set | ❌ Missing | Immutable collection |
| `FrozenSet[T]` | Typed frozenset | ❌ Missing | Immutable collection |

**Constrained Set Parameters** (via `conset`/`confrozenset`):
- `item_type` - ⚠️ Partial
- `min_length` - ❌ Missing
- `max_length` - ❌ Missing

### Dictionary Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `dict` | Standard dict | ✅ Full | Native support |
| `Dict[K, V]` | Typed dict | ✅ Full | Generic support |
| `Mapping[K, V]` | Mapping protocol | ⚠️ Partial | Can validate as dict |
| `MutableMapping[K, V]` | Mutable mapping | ⚠️ Partial | Can validate as dict |
| `OrderedDict` | Ordered dictionary | ❌ Missing | Ordered collection |
| `DefaultDict` | Dict with default | ❌ Missing | Special dict |
| `Counter` | Counter dict | ❌ Missing | Special dict |

### Other Collections

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `Deque[T]` | Double-ended queue | ❌ Missing | Special collection |

---

## 7. Special Types

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `bool` | Boolean | ✅ Full | Native support |
| `StrictBool` | Strict boolean | ⚠️ Partial | Can implement |
| `UUID` | UUID (any version) | ⚠️ Partial | Basic support |
| `UUID1` | UUID version 1 | ❌ Missing | Specific UUID version |
| `UUID3` | UUID version 3 | ❌ Missing | Specific UUID version |
| `UUID4` | UUID version 4 | ❌ Missing | Specific UUID version |
| `UUID5` | UUID version 5 | ❌ Missing | Specific UUID version |
| `UUID6` | UUID version 6 | ❌ Missing | Specific UUID version |
| `UUID7` | UUID version 7 | ❌ Missing | Specific UUID version |
| `UUID8` | UUID version 8 | ❌ Missing | Specific UUID version |
| `Json` | JSON-serializable value | ⚠️ Partial | Can validate structure |
| `JsonValue` | Recursive JSON type | ⚠️ Partial | Type alias |
| `Base64Bytes` | Base64 encoded bytes | ❌ Missing | Encoding type |
| `Base64Str` | Base64 encoded string | ❌ Missing | Encoding type |
| `Base64UrlBytes` | Base64 URL-safe bytes | ❌ Missing | Encoding type |
| `Base64UrlStr` | Base64 URL-safe string | ❌ Missing | Encoding type |
| `EncodedBytes` | Generic encoded bytes | ❌ Missing | Encoding type |
| `EncodedStr` | Generic encoded string | ❌ Missing | Encoding type |

---

## 8. Constrained Types

### Constrained Type Functions

Pydantic provides these functions (being deprecated in v3.0 in favor of `Annotated` + `Field`):

| Function | Purpose | Satya Equivalent | Status |
|----------|---------|------------------|--------|
| `constr()` | Constrained string | `Field(min_length=, max_length=, pattern=)` | ✅ Supported |
| `conint()` | Constrained integer | `Field(gt=, ge=, lt=, le=)` | ✅ Supported |
| `confloat()` | Constrained float | `Field(gt=, ge=, lt=, le=)` | ✅ Supported |
| `conbytes()` | Constrained bytes | `Field(min_length=, max_length=)` | ⚠️ Partial |
| `conlist()` | Constrained list | `Field(min_items=, max_items=)` | ✅ Supported |
| `conset()` | Constrained set | N/A | ❌ Missing |
| `confrozenset()` | Constrained frozenset | N/A | ❌ Missing |
| `condate()` | Constrained date | N/A | ❌ Missing |
| `condecimal()` | Constrained decimal | `Field(gt=, ge=, lt=, le=)` | ⚠️ Partial |

---

## 9. Advanced Type Features

### Union and Optional Types

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `Union[A, B, ...]` | Multiple type options | ✅ Full | Native support |
| `Optional[T]` | T or None | ✅ Full | Native support |
| `Literal[...]` | Literal values | ⚠️ Partial | Via enum |
| `Annotated[T, ...]` | Type with metadata | ⚠️ Partial | Basic support |

### Discriminated Unions

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| Tagged unions | Union with discriminator field | ❌ Missing | Advanced feature |
| `Field(discriminator=...)` | Discriminator specification | ❌ Missing | Advanced feature |

### Generic Types

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `Generic[T]` | Generic models | ⚠️ Partial | Basic support |
| `TypeVar` | Type variables | ⚠️ Partial | Basic support |
| Constrained TypeVar | TypeVar with bounds | ❌ Missing | Advanced feature |
| Generic specialization | Parameterized generics | ❌ Missing | Advanced feature |

### Recursive and Forward References

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| Self-referential models | Models that reference themselves | ⚠️ Partial | Basic support |
| Forward references | String annotations | ⚠️ Partial | Basic support |
| `model_rebuild()` | Resolve forward refs | ❌ Missing | Advanced feature |

### Callable Types

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `Callable[[Args], Return]` | Function types | ❌ Missing | Advanced feature |

### Any Type

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `Any` | Accept any type | ✅ Full | Native support |

---

## 10. Pydantic-Extra-Types

These types have been moved to the `pydantic-extra-types` package:

| Type | Description | Satya Support | Notes |
|------|-------------|---------------|-------|
| `Color` | Color values | ❌ Missing | Moved to extra-types |
| `PaymentCardNumber` | Credit card numbers | ❌ Missing | Moved to extra-types |
| `PaymentCardBrand` | Card brand detection | ❌ Missing | Moved to extra-types |

**Note**: `BaseSettings` has also been moved to `pydantic-settings` package.

---

## 11. Gap Analysis

### Critical Gaps (High Priority)

1. **Numeric Constraints**
   - ❌ `multiple_of` for int/float/decimal
   - ❌ `max_digits` and `decimal_places` for Decimal
   - ❌ `allow_inf_nan` for float
   - ❌ `FiniteFloat` type

2. **Date/Time Constraints**
   - ❌ Past/Future date/datetime validation
   - ❌ Timezone-aware/naive datetime validation
   - ❌ Date range constraints (gt, ge, lt, le)

3. **Network Types**
   - ❌ Comprehensive URL types (FTP, WebSocket, etc.)
   - ❌ IP address types (IPv4, IPv6, Interface, Network)
   - ❌ Database DSN types (PostgreSQL, MySQL, Redis, etc.)

4. **File Types**
   - ❌ File/Directory path validation
   - ❌ Path existence checking

5. **Collection Constraints**
   - ❌ Set/FrozenSet with constraints
   - ❌ Deque support
   - ❌ OrderedDict, DefaultDict, Counter

### Medium Priority Gaps

6. **String Features**
   - ❌ `SecretStr`/`SecretBytes` (security)
   - ❌ `to_upper`/`to_lower` transformations
   - ❌ `ImportString` type

7. **Special Types**
   - ❌ UUID version-specific types
   - ❌ Base64 encoding types
   - ❌ `ByteSize` type

8. **Advanced Features**
   - ❌ Discriminated unions
   - ❌ Callable types
   - ❌ Generic type specialization
   - ❌ `model_rebuild()` for forward references

### Low Priority Gaps

9. **Extra Types**
   - ❌ Color validation
   - ❌ Payment card validation

10. **Other**
    - ❌ Complex number support
    - ❌ NamedTuple support

---

## 12. Recommendations

### Phase 1: Core Numeric & Date Enhancements (Immediate)

**Priority**: Critical for feature parity

1. **Add `multiple_of` constraint** for int/float/decimal
   - Implementation: Add to Field parameters
   - Validation: Python-side check
   - Estimated effort: 2-4 hours

2. **Add Decimal precision constraints**
   - `max_digits`: Maximum total digits
   - `decimal_places`: Maximum decimal places
   - Estimated effort: 4-6 hours

3. **Add date/time range constraints**
   - Past/Future validators
   - Date comparison (gt, ge, lt, le)
   - Estimated effort: 6-8 hours

4. **Add `FiniteFloat` and `allow_inf_nan`**
   - Validate against inf/-inf/nan
   - Estimated effort: 2-4 hours

### Phase 2: Network & File Types (High Value)

**Priority**: High for real-world applications

5. **Implement IP address types**
   - IPv4Address, IPv6Address
   - IPv4Network, IPv6Network
   - IPv4Interface, IPv6Interface
   - Use Python's `ipaddress` module
   - Estimated effort: 8-12 hours

6. **Implement comprehensive URL types**
   - HttpUrl, FtpUrl, WebsocketUrl
   - URL parsing and validation
   - Estimated effort: 6-10 hours

7. **Implement file path types**
   - FilePath, DirectoryPath
   - Path existence validation
   - Estimated effort: 4-6 hours

8. **Implement database DSN types**
   - PostgresDsn, MySQLDsn, RedisDsn, etc.
   - DSN parsing and validation
   - Estimated effort: 10-15 hours

### Phase 3: Collection & Special Types (Medium Priority)

9. **Add Set/FrozenSet constraints**
   - min_length, max_length
   - Estimated effort: 4-6 hours

10. **Add UUID version validation**
    - UUID1-UUID8 specific validators
    - Estimated effort: 4-6 hours

11. **Add SecretStr/SecretBytes**
    - Concealed repr for security
    - Estimated effort: 3-5 hours

12. **Add Base64 encoding types**
    - Base64Bytes, Base64Str
    - Base64UrlBytes, Base64UrlStr
    - Estimated effort: 6-8 hours

### Phase 4: Advanced Features (Future)

13. **Implement discriminated unions**
    - Tagged union support
    - Discriminator field
    - Estimated effort: 15-20 hours

14. **Implement Callable types**
    - Function signature validation
    - Estimated effort: 10-15 hours

15. **Enhance generic type support**
    - TypeVar bounds
    - Generic specialization
    - Estimated effort: 20-30 hours

---

## Summary Statistics

### Current Coverage

**Total Pydantic Types Analyzed**: ~150+

**Satya Support Breakdown**:
- ✅ **Full Support**: ~40 types (27%)
- ⚠️ **Partial Support**: ~35 types (23%)
- ❌ **Missing**: ~75 types (50%)

### Priority Distribution

- **Critical Gaps**: 15 items
- **High Priority**: 10 items
- **Medium Priority**: 20 items
- **Low Priority**: 30 items

### Estimated Implementation Effort

- **Phase 1** (Critical): 14-22 hours
- **Phase 2** (High Value): 28-43 hours
- **Phase 3** (Medium Priority): 17-25 hours
- **Phase 4** (Advanced): 45-65 hours

**Total Estimated Effort**: 104-155 hours (13-19 days)

---

## Conclusion

Satya currently supports the core type system well, with strong coverage of basic types, strings, numbers, and simple collections. However, there are significant opportunities to enhance Satya's type system to achieve feature parity with Pydantic:

### Strengths
- ✅ Excellent core type support (str, int, float, bool)
- ✅ Strong constraint system (min/max length, ge/le/gt/lt)
- ✅ Good collection support (List, Dict)
- ✅ Email and basic URL validation
- ✅ Decimal support
- ✅ Union and Optional types

### Key Gaps to Address
- ❌ Numeric constraints (multiple_of, decimal precision)
- ❌ Date/time constraints (past/future, timezone-aware)
- ❌ Comprehensive network types (IP, DSN)
- ❌ File path validation
- ❌ Advanced collection types (Set, FrozenSet, Deque)
- ❌ Security types (SecretStr, SecretBytes)
- ❌ Discriminated unions

### Strategic Recommendation

Focus on **Phase 1 and Phase 2** to achieve 80% feature parity with Pydantic for real-world use cases. This will position Satya as a high-performance, feature-complete alternative to Pydantic while maintaining its performance advantages.

**Next Action**: Prioritize implementation of Phase 1 (Core Numeric & Date Enhancements) to close the most critical gaps.

---

## 13. Validation Features

### Validation Decorators

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `@field_validator` | Field-level validation (V2) | ✅ Implemented | Custom validation logic |
| `@model_validator` | Model-level validation (V2) | ✅ Implemented | Cross-field validation |
| `@validator` | Field validation (V1, deprecated) | ❌ Missing | Legacy feature |
| `@root_validator` | Model validation (V1, deprecated) | ❌ Missing | Legacy feature |

### Functional Validators

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `BeforeValidator` | Pre-validation logic | ❌ Missing | With Annotated |
| `AfterValidator` | Post-validation logic | ❌ Missing | With Annotated |
| `PlainValidator` | Replace validation | ❌ Missing | With Annotated |
| `WrapValidator` | Wrap validation | ❌ Missing | With Annotated |

### Validation Methods

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `model_validate()` | Validate dict/object | ✅ Full | Implemented |
| `model_validate_json()` | Validate JSON string | ✅ Full | Implemented |
| `TypeAdapter` | Validate arbitrary types | ❌ Missing | Advanced feature |
| `ValidationInfo` | Access validation context | ❌ Missing | In validators |

---

## 14. Serialization Features

### Serialization Methods

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `model_dump()` | Serialize to dict | ✅ Full | Implemented |
| `model_dump_json()` | Serialize to JSON | ✅ Full | Implemented |
| `mode='json'` | JSON-safe serialization | ⚠️ Partial | Basic support |
| Include/exclude fields | Control output | ⚠️ Partial | Basic support |

### Serialization Decorators

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `@field_serializer` | Custom field serialization | ❌ Missing | Customization |
| `@model_serializer` | Custom model serialization | ❌ Missing | Customization |
| `PlainSerializer` | Functional serializer | ❌ Missing | With Annotated |
| `WrapSerializer` | Wrap serializer | ❌ Missing | With Annotated |
| `when_used='json'` | Conditional serialization | ❌ Missing | JSON-specific |

---

## 15. Computed Fields & Properties

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `@computed_field` | Computed attributes | ❌ Missing | Dynamic fields |
| `@property` | Python property | ⚠️ Partial | Basic support |
| `@cached_property` | Cached computed field | ❌ Missing | Performance |
| Computed field in schema | Include in JSON Schema | ❌ Missing | Schema generation |

---

## 16. Private Attributes

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `PrivateAttr()` | Private model attributes | ❌ Missing | Not serialized |
| `__pydantic_private__` | Private storage | ❌ Missing | Internal dict |
| Exclude from validation | Skip validation | ❌ Missing | Performance |

---

## 17. Model Configuration

### Configuration Options

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `model_config` | Configuration dict | ⚠️ Partial | Basic support |
| `ConfigDict` | Type-safe config | ⚠️ Partial | Basic support |
| `extra='allow'` | Allow extra fields | ✅ Full | Implemented |
| `extra='forbid'` | Forbid extra fields | ✅ Full | Implemented |
| `extra='ignore'` | Ignore extra fields | ✅ Full | Implemented |
| `validate_assignment` | Validate on assignment | ⚠️ Partial | Basic support |
| `alias_generator` | Auto-generate aliases | ❌ Missing | Naming convention |
| `serialize_by_alias` | Use aliases in output | ❌ Missing | Serialization |
| `populate_by_name` | Accept field name or alias | ❌ Missing | Validation |
| `str_strip_whitespace` | Strip string whitespace | ⚠️ Partial | In validation |
| `str_to_lower` | Convert to lowercase | ❌ Missing | Transformation |
| `str_to_upper` | Convert to uppercase | ❌ Missing | Transformation |
| `strict` | Strict mode validation | ⚠️ Partial | Type coercion |
| `frozen` | Immutable model | ❌ Missing | Immutability |
| `use_enum_values` | Use enum values | ❌ Missing | Enum handling |
| `arbitrary_types_allowed` | Allow custom types | ⚠️ Partial | Custom types |

---

## 18. Field Aliases

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `Field(alias=...)` | Field alias | ⚠️ Partial | Basic support |
| `Field(validation_alias=...)` | Validation-only alias | ❌ Missing | Input alias |
| `Field(serialization_alias=...)` | Serialization-only alias | ❌ Missing | Output alias |
| `AliasPath` | Nested field path | ❌ Missing | Complex aliasing |
| `AliasChoices` | Multiple alias options | ❌ Missing | Flexible input |

---

## 19. Additional Features

### Schema Generation

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `model_json_schema()` | Generate JSON Schema | ✅ Full | Implemented |
| `schema()` | Get schema dict | ✅ Full | Implemented |
| Custom schema generation | `__get_pydantic_core_schema__` | ❌ Missing | Advanced |
| Custom JSON schema | `__get_pydantic_json_schema__` | ❌ Missing | Advanced |

### Model Methods

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `model_construct()` | Skip validation | ✅ Full | Implemented |
| `model_copy()` | Copy with updates | ❌ Missing | Immutability |
| `model_rebuild()` | Rebuild schema | ❌ Missing | Forward refs |
| `model_fields` | Field metadata | ⚠️ Partial | Via __fields__ |
| `model_fields_set` | Set fields | ❌ Missing | Tracking |

### Error Handling

| Feature | Description | Satya Support | Notes |
|---------|-------------|---------------|-------|
| `ValidationError` | Validation errors | ✅ Full | Implemented |
| Error customization | Custom error messages | ⚠️ Partial | Basic support |
| Error locations | Field paths | ✅ Full | Implemented |
| Multiple errors | Collect all errors | ✅ Full | Implemented |

---

## 20. Updated Gap Analysis

### Additional Critical Gaps

**Validation Features**:
- ❌ `@field_validator` and `@model_validator` decorators
- ❌ Functional validators (Before/After/Plain/Wrap)
- ❌ `ValidationInfo` context

**Serialization Features**:
- ❌ `@field_serializer` and `@model_serializer` decorators
- ❌ Conditional serialization (`when_used='json'`)
- ❌ Functional serializers

**Computed Fields**:
- ❌ `@computed_field` decorator
- ❌ Computed fields in JSON Schema

**Configuration**:
- ❌ `alias_generator` for auto-aliasing
- ❌ `frozen` for immutable models
- ❌ `use_enum_values` for enum handling
- ❌ String transformation (to_lower, to_upper)

**Aliases**:
- ❌ `validation_alias` and `serialization_alias`
- ❌ `AliasPath` and `AliasChoices`

**Model Methods**:
- ❌ `model_copy()` for updates
- ❌ `model_rebuild()` for forward refs
- ❌ `model_fields_set` tracking

---

## 21. Updated Recommendations

### Phase 1A: Validation System (Critical)

**Priority**: Essential for custom validation logic

1. **Implement `@field_validator` decorator**
   - Support 'before', 'after', 'plain', 'wrap' modes
   - Estimated effort: 15-20 hours

2. **Implement `@model_validator` decorator**
   - Support 'before' and 'after' modes
   - Cross-field validation
   - Estimated effort: 10-15 hours

3. **Implement functional validators**
   - BeforeValidator, AfterValidator
   - PlainValidator, WrapValidator
   - Estimated effort: 12-18 hours

### Phase 1B: Serialization System (High Priority)

4. **Implement `@field_serializer` decorator**
   - Custom field serialization
   - Conditional serialization
   - Estimated effort: 10-15 hours

5. **Implement `@model_serializer` decorator**
   - Custom model serialization
   - Estimated effort: 8-12 hours

### Phase 1C: Computed Fields (Medium Priority)

6. **Implement `@computed_field` decorator**
   - Dynamic field calculation
   - Include in serialization
   - Estimated effort: 8-12 hours

### Phase 1D: Configuration Enhancements (Medium Priority)

7. **Implement `alias_generator`**
   - Auto-generate field aliases
   - Support common naming conventions
   - Estimated effort: 6-10 hours

8. **Implement `frozen` models**
   - Immutable model instances
   - Estimated effort: 4-6 hours

9. **Implement advanced alias types**
   - `validation_alias` and `serialization_alias`
   - `AliasPath` and `AliasChoices`
   - Estimated effort: 10-15 hours

---

## 22. Updated Summary Statistics

### Total Features Analyzed

**Total Pydantic Features**: ~200+

**Satya Support Breakdown**:
- ✅ **Full Support**: ~50 features (25%)
- ⚠️ **Partial Support**: ~50 features (25%)
- ❌ **Missing**: ~100 features (50%)

### Updated Priority Distribution

- **Critical Gaps**: 30 items (validation, serialization, core types)
- **High Priority**: 20 items (network types, file types, configuration)
- **Medium Priority**: 30 items (computed fields, aliases, advanced features)
- **Low Priority**: 20 items (extra types, legacy features)

### Updated Implementation Effort

- **Phase 1A** (Validation): 37-53 hours
- **Phase 1B** (Serialization): 18-27 hours
- **Phase 1C** (Computed Fields): 8-12 hours
- **Phase 1D** (Configuration): 20-31 hours
- **Phase 2** (Network & File Types): 28-43 hours
- **Phase 3** (Collection & Special Types): 17-25 hours
- **Phase 4** (Advanced Features): 45-65 hours

**Total Updated Effort**: 173-256 hours (22-32 days)

---

## 23. Final Conclusion

Satya has a solid foundation with excellent performance characteristics and good coverage of core types. However, to achieve feature parity with Pydantic and become a drop-in replacement, significant work is needed in:

### Top 5 Priority Areas

1. **Validation System** (37-53 hours)
   - Critical for custom validation logic
   - Essential for real-world applications
   - Highest user demand

2. **Serialization System** (18-27 hours)
   - Important for API responses
   - Custom output formatting
   - High user demand

3. **Core Type Enhancements** (14-22 hours)
   - Numeric constraints (multiple_of, decimal precision)
   - Date/time constraints
   - Immediate value

4. **Network & File Types** (28-43 hours)
   - High value for web applications
   - Database integrations
   - Real-world use cases

5. **Configuration & Aliases** (20-31 hours)
   - Flexible naming conventions
   - Immutable models
   - API compatibility

### Strategic Path Forward

**Short-term** (1-2 months):
- Implement validation system (Phase 1A)
- Implement serialization system (Phase 1B)
- Add core type enhancements (Phase 1 from original plan)

**Medium-term** (3-4 months):
- Implement computed fields (Phase 1C)
- Add configuration enhancements (Phase 1D)
- Implement network & file types (Phase 2)

**Long-term** (5-6 months):
- Add collection & special types (Phase 3)
- Implement advanced features (Phase 4)
- Achieve 95%+ Pydantic compatibility

### Success Metrics

- **3 months**: 60% feature parity
- **6 months**: 85% feature parity
- **9 months**: 95% feature parity
- **Performance**: Maintain 5-20x speed advantage over Pydantic

---

**Document Version**: 2.0  
**Last Updated**: 2025-10-09  
**Maintained By**: Satya Development Team
