Remove pydantic v1 runtime compat layer (#3025)

* Extract shared pydantic base module for v2/dataclass/msgspec

* fix: eliminate code duplication in pydantic v1 modules for coverage

* Remove pydantic v1 runtime compat layer

* docs: update CLI reference documentation and prompt data

🤖 Generated by GitHub Actions

* Remove unnecessary pragma: no cover from process_const

* Fix coverage: remove dead v1 guards and unused test

* Remove pragma: no cover added by mistake during backup checkout

* Trigger CI

* Restore pragma: no cover for genuinely unreachable code paths

* Add pragma: no cover to unused compat functions pending removal in PR3

* Fix coverage: add pragma to return statements of unused compat functions

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: koxudaxi

.github/workflows/test.yaml

@@ -39,8 +39,6 @@ jobs:
             name: py312-isort6
           - tox_env: py312-isort5-parallel
             name: py312-isort5
-          - tox_env: py312-pydantic1-parallel
-            name: py312-pydantic1
     runs-on: ${{ matrix.os == '' && 'ubuntu-24.04' || matrix.os }}
     env:
       OS: ${{ matrix.os == '' && 'ubuntu-24.04' || matrix.os}}

pyproject.toml

@@ -216,7 +216,6 @@ skip = '.git,*.lock,tests,docs/cli-reference,CHANGELOG.md,docs/changelog.md,docs
 [tool.pytest.ini_options]
 filterwarnings = [
   "error",
-  "ignore:^.*Pydantic v1 runtime support is deprecated.*:DeprecationWarning",
   "ignore:^.*No --output-model-type specified.*:DeprecationWarning",
   "ignore:^.*Pydantic v2 with --use-annotated is recommended.*:DeprecationWarning",
   "ignore:^.*`--validation` option is deprecated.*",

src/datamodel_code_generator/__init__.py

@@ -80,16 +80,9 @@
 T = TypeVar("T")
 _ConfigT = TypeVar("_ConfigT", bound="ParserConfig")
 
-# Import is_pydantic_v2 here for module-level YamlValue type definition
-from datamodel_code_generator.util import is_pydantic_v2  # noqa: E402
-
 if not TYPE_CHECKING:  # pragma: no branch
     YamlScalar: TypeAlias = str | int | float | bool | None
-    if is_pydantic_v2():
-        YamlValue = TypeAliasType("YamlValue", "dict[str, YamlValue] | list[YamlValue] | YamlScalar")
-    else:
-        # Pydantic v1 cannot handle TypeAliasType, use Any for recursive parts
-        YamlValue: TypeAlias = dict[str, Any] | list[Any] | YamlScalar
+    YamlValue = TypeAliasType("YamlValue", "dict[str, YamlValue] | list[YamlValue] | YamlScalar")
 
 
 GeneratedModules: TypeAlias = dict[tuple[str, ...], str]
@@ -471,19 +464,13 @@ def _create_parser_config(
     Filters GenerateConfig fields to only those expected by the parser config class,
     then merges with additional_options.
     """
-    if is_pydantic_v2():
-        parser_config_fields = set(config_class.model_fields.keys())
-        all_options = {
-            k: v
-            for k, v in generate_config.model_dump().items()
-            if k in parser_config_fields and k not in additional_options
-        } | dict(additional_options)
-        return config_class.model_validate(all_options)
-    parser_config_fields = set(config_class.__fields__.keys())
+    parser_config_fields = set(config_class.model_fields.keys())
     all_options = {
-        k: v for k, v in generate_config.dict().items() if k in parser_config_fields and k not in additional_options
+        k: v
+        for k, v in generate_config.model_dump().items()
+        if k in parser_config_fields and k not in additional_options
     } | dict(additional_options)
-    return config_class.parse_obj(all_options)
+    return config_class.model_validate(all_options)
 
 
 def generate(  # noqa: PLR0912, PLR0914, PLR0915
@@ -518,18 +505,11 @@ def generate(  # noqa: PLR0912, PLR0914, PLR0915
         raise ValueError(msg)
 
     if config is None:
-        if is_pydantic_v2():
-            from datamodel_code_generator.model.pydantic_v2 import UnionMode  # noqa: PLC0415
-            from datamodel_code_generator.types import StrictTypes  # noqa: PLC0415
+        from datamodel_code_generator.model.pydantic_v2 import UnionMode  # noqa: PLC0415
+        from datamodel_code_generator.types import StrictTypes  # noqa: PLC0415
 
-            GenerateConfig.model_rebuild(_types_namespace={"StrictTypes": StrictTypes, "UnionMode": UnionMode})
-            config = GenerateConfig.model_validate(options)
-        else:
-            from datamodel_code_generator.enums import UnionMode  # noqa: PLC0415
-            from datamodel_code_generator.types import StrictTypes  # noqa: PLC0415
-
-            GenerateConfig.update_forward_refs(StrictTypes=StrictTypes, UnionMode=UnionMode)
-            config = GenerateConfig(**options)
+        GenerateConfig.model_rebuild(_types_namespace={"StrictTypes": StrictTypes, "UnionMode": UnionMode})
+        config = GenerateConfig.model_validate(options)
 
     # Variables that may be modified during processing
     input_filename = config.input_filename
@@ -979,13 +959,6 @@ def __getattr__(name: str) -> Any:
     if name in _LAZY_IMPORTS:
         import importlib  # noqa: PLC0415
 
-        if name == "GenerateConfig" and not is_pydantic_v2():  # pragma: no cover
-            msg = (
-                f"'{name}' is only available in Pydantic v2 environments. "
-                "Use 'from datamodel_code_generator.config import GenerateConfig' instead."
-            )
-            raise ImportError(msg)
-
         module = importlib.import_module(_LAZY_IMPORTS[name])
         return getattr(module, name)
     msg = f"module {__name__!r} has no attribute {name!r}"
@@ -1034,5 +1007,4 @@ def __getattr__(name: str) -> Any:
     "generate_dynamic_models",  # noqa: F822
 ]
 
-if is_pydantic_v2():  # pragma: no cover
-    __all__ += ["GenerateConfig"]
+__all__ += ["GenerateConfig"]