First-class Pydantic v2+ support

RELEASE.md

@@ -0,0 +1,77 @@
+Release type: minor
+
+Add first-class support for Pydantic v2+ models in Strawberry GraphQL.
+
+This release introduces a new `strawberry.pydantic` module that allows you to directly
+decorate Pydantic `BaseModel` classes to create GraphQL types, inputs, and interfaces
+without requiring separate wrapper classes.
+
+## Basic Usage
+
+```python
+import strawberry
+from pydantic import BaseModel
+
+
+@strawberry.pydantic.type
+class User(BaseModel):
+    name: str
+    age: int
+
+
+@strawberry.pydantic.input
+class CreateUserInput(BaseModel):
+    name: str
+    age: int
+```
+
+## Features
+
+- `@strawberry.pydantic.type` - Convert Pydantic models to GraphQL types
+- `@strawberry.pydantic.input` - Convert Pydantic models to GraphQL input types
+- `@strawberry.pydantic.interface` - Convert Pydantic models to GraphQL interfaces
+- Automatic field extraction from Pydantic models
+- Pydantic field descriptions preserved in GraphQL schema
+- Pydantic field aliases used as GraphQL field names
+- Support for `strawberry.Private` to exclude fields from schema
+- Support for `strawberry.field()` with `Annotated` for directives, permissions, deprecation
+- Generic Pydantic model support
+- `strawberry.pydantic.Error` type for validation error handling in union return types
+
+## Migration from Experimental
+
+The experimental `strawberry.experimental.pydantic` integration is now deprecated.
+See the documentation for migration guide.
+
+---
+
+## TODO: Improvements Needed Before/After Release
+
+### Documentation Fixes
+- [x] Remove or implement `from_pydantic()`/`to_pydantic()` methods mentioned in docs
+- [x] Update test snapshots for Pydantic version (2.11 → 2.12) - made assertions version-agnostic
+
+### Code Quality
+- [x] Replace `typing._GenericAlias` private API usage - now uses `is_generic_alias` utility
+- [x] Narrow exception handling in `schema_converter.py` - refactored to `_maybe_convert_validation_error`
+- [x] Add computed field tests to verify `include_computed` works with `@computed_field`
+
+### Future Pydantic v2 Features to Implement
+
+#### High Priority
+- [ ] Validation context - Pass `strawberry.Info` to Pydantic validators
+- [ ] Honor `model_config` settings (`strict`, `extra='forbid'`, etc.)
+- [ ] Expose `@field_validator` errors in a structured way
+
+#### Medium Priority
+- [ ] Discriminated unions - Use `__typename` as discriminator
+- [ ] `@model_validator` support for cross-field validation
+- [ ] Separate input/output aliases (`validation_alias` vs `serialization_alias`)
+- [ ] Strict mode configuration per field/type
+
+#### Low Priority
+- [ ] `TypeAdapter` support for non-model types
+- [ ] `RootModel` support for custom scalar-like types
+- [ ] Custom serializers via `@model_serializer`
+- [ ] JSON schema generation integration
+- [ ] Functional validators (`BeforeValidator`, `AfterValidator`, etc.)