feat: Add support for type: ignore comments in stub generation

[konn]

Summary

This PR adds support for # type: ignore comments in generated Python stub files, enabling developers to suppress specific type checker warnings from MyPy and Pyright.

Key Features

• Comprehensive rule support: 70+ predefined MyPy error codes and Pyright diagnostic rules
• Custom rule fallback: Unknown rules are preserved as Custom variants
• Dual target support: Works for both standalone functions and class methods
• Compile-time validation: Warnings for empty rule lists and unknown rules
• Clean syntax: #[gen_stub(type_ignore = ["rule1", "rule2"])] attribute

Usage Examples

// Functions
#[gen_stub_pyfunction]
#[gen_stub(type_ignore = ["arg-type", "return-value"])]
#[pyfunction]
fn my_function() -> i32 { 42 }

// Methods
#[pymethods]
#[gen_stub_pymethods]
impl MyClass {
    #[gen_stub(type_ignore = ["union-attr", "return-value"])]
    fn my_method(&self) -> i32 { 42 }
}

Generated Output

def my_function() -> builtins.int:  # type: ignore[arg-type,return-value]
    """Function docstring"""

class MyClass:
    def my_method(self) -> builtins.int:  # type: ignore[union-attr,return-value]
        """Method docstring"""

Implementation Details

• New module: type_check_rule.rs with comprehensive RuleName enum
• Extended data structures: Added type_ignored field to PyFunctionInfo and MethodInfo
• Proc-macro support: Enhanced attribute parsing for type_ignore parameter
• Standard traits: Implements FromStr and Display for RuleName
• Backward compatibility: No breaking changes to existing APIs

Supported Rule Categories

• MyPy error codes: arg-type, return-value, attr-defined, union-attr, etc.
• Pyright diagnostics: reportGeneralTypeIssues, reportReturnType, etc.
• Custom rules: Any unknown rule name is preserved for future compatibility

Test Coverage

• Comprehensive test cases for functions and methods
• Validation of MyPy and Pyright rule parsing
• Custom rule handling verification
• Warning generation for empty rule lists

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR adds comprehensive support for generating # type: ignore comments in Python stub files, enabling developers to suppress specific type checker warnings from MyPy and Pyright. The implementation includes a new rule name system with 70+ predefined error codes and custom rule support.

Key changes:

• New RuleName enum with comprehensive MyPy and Pyright diagnostic rule support
• Enhanced proc-macro attribute parsing for type_ignore parameter
• Extended data structures to store type ignore rules in function and method metadata

Reviewed Changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
pyo3-stub-gen/src/type_info.rs	Added type_ignored field to MethodInfo and PyFunctionInfo structs
pyo3-stub-gen/src/rule_name.rs	New module defining comprehensive RuleName enum with MyPy/Pyright rules
pyo3-stub-gen/src/lib.rs	Added rule_name module export
pyo3-stub-gen/src/generate/function.rs	Enhanced function generation with type ignore comment support
pyo3-stub-gen/src/generate/method.rs	Enhanced method generation with type ignore comment support
pyo3-stub-gen/src/generate/class.rs	Updated auto-generated methods to include None type_ignored field
pyo3-stub-gen/src/generate/variant_methods.rs	Updated variant methods to include None type_ignored field
pyo3-stub-gen-derive/src/gen_stub/pyfunction.rs	Added type_ignore attribute parsing for functions
pyo3-stub-gen-derive/src/gen_stub/method.rs	Added type_ignore attribute parsing for methods
pyo3-stub-gen-derive/src/gen_stub/attr.rs	Enhanced attribute parser with TypeIgnore variant
examples/pure/src/lib.rs	Added comprehensive test cases for type ignore functionality
examples/pure/pure.pyi	Generated stub examples showing type ignore comments

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[termoshtt]

LGTM