# Spec: Code Quality Improvements

## ADDED Requirements

### Requirement: Specific Exception Catching
The adapter SHALL NOT use bare `except:` clauses which catch `SystemExit` and `KeyboardInterrupt`. It SHALL catch specific exceptions when validating configuration or connection parameters.

#### Scenario: Invalid Protocol Version
- **GIVEN** a `credentials` object with an invalid `protocol_version`
- **WHEN** `ExasolConnectionManager.open()` is called
- **THEN** a `DbtRuntimeError` is raised wrapping the specific underlying error (e.g., `ValueError` or `KeyError`)
- **AND** the application remains responsive to interrupts

### Requirement: Unused Imports
The codebase SHALL NOT contain unused imports in source files or tests, unless explicitly required for side-effects or re-exports (which should be documented or included in `__all__`).

#### Scenario: Clean Module Imports
- **GIVEN** the `dbt.adapters.exasol` package
- **WHEN** inspected by a linter
- **THEN** no unused imports are reported in `__init__.py` or other modules

### Requirement: Consistent Formatting
SQL and Jinja macros SHALL follow standard formatting rules defined by the project's `sqlfluff` configuration, including indentation and spacing.

#### Scenario: Formatted Macros
- **GIVEN** a macro file in `dbt/include/exasol/macros/`
- **WHEN** `sqlfluff lint` is run on the file
- **THEN** no formatting violations are reported

### Requirement: Empty Identifier Guard
The `is_valid_identifier()` method SHALL handle empty strings gracefully without raising an exception.

#### Scenario: Empty String Input
- **GIVEN** an empty string `""`
- **WHEN** `ExasolAdapter.is_valid_identifier("")` is called
- **THEN** the method returns `False`
- **AND** no `IndexError` is raised
