Feb 11, 2026 · Feb 11, 2026
diff --git a/fastapi/_compat/v2.py b/fastapi/_compat/v2.py
 from typing import (
    Annotated,
    Any,
    Literal,
    Union,
    cast,
    get_args,
    get_origin,
 )

 from fastapi._compat import lenient_issubclass, shared
 from pydantic_core.core_schema import (
    with_info_plain_validator_function as with_info_plain_validator_function,
 )
 from typing_extensions import Literal, get_args, get_origin

 RequiredParam = PydanticUndefined
 Undefined = PydanticUndefined
    field_info: FieldInfo
    name: str
    mode: Literal["validation", "serialization"] = "validation"
    config:Union[ConfigDict,None] = None
    config: ConfigDict |None = None

    @property
    def alias(self) -> str:
        a = self.field_info.alias
        return a if a is not None else self.name

    @property
    def validation_alias(self) ->Union[str,None]:
    def validation_alias(self) -> str |None:
        va = self.field_info.validation_alias
        if isinstance(va, str) and va:
            return va
        return None

    @property
    def serialization_alias(self) ->Union[str,None]:
    def serialization_alias(self) -> str |None:
        sa = self.field_info.serialization_alias
        return sa or None

        value: Any,
        values: dict[str, Any] = {},  # noqa: B006
        *,
        loc: tuple[Union[int,str], ...] = (),
        loc: tuple[int |str, ...] = (),
    ) -> tuple[Any, list[dict[str, Any]]]:
        try:
            return (
        value: Any,
        *,
        mode: Literal["json", "python"] = "json",
        include:Union[IncEx,None] = None,
        exclude:Union[IncEx,None] = None,
        include: IncEx |None = None,
        exclude: IncEx |None = None,
        by_alias: bool = True,
        exclude_unset: bool = False,
        exclude_defaults: bool = False,
    ],
    separate_input_output_schemas: bool = True,
 ) -> dict[str, Any]:
    override_mode:Union[Literal["validation"],None] = (
    override_mode: Literal["validation"] |None = (
        None
        if (separate_input_output_schemas or _has_computed_fields(field))
        else "validation"
    return shared.sequence_annotation_to_type[origin_type](value)  # type: ignore[no-any-return,index]


 def get_missing_field_error(loc: tuple[Union[int,str], ...]) -> dict[str, Any]:
 def get_missing_field_error(loc: tuple[int |str, ...]) -> dict[str, Any]:
    error = ValidationError.from_exception_data(
        "Field required", [{"type": "missing", "loc": loc, "input": {}}]
    ).errors(include_url=False)[0]
 # Duplicate of several schema functions from Pydantic v1 to make them compatible with
 # Pydantic v2 and allow mixing the models

 TypeModelOrEnum =Union[type["BaseModel"],type[Enum]]
 TypeModelOrEnum = type["BaseModel"] |type[Enum]
 TypeModelSet = set[TypeModelOrEnum]




 def get_flat_models_from_model(
    model: type["BaseModel"], known_models:Union[TypeModelSet,None] = None
    model: type["BaseModel"], known_models: TypeModelSet |None = None
 ) -> TypeModelSet:
    known_models = known_models or set()
    fields = get_model_fields(model)


 def _regenerate_error_with_loc(
    *, errors: Sequence[Any], loc_prefix: tuple[Union[str,int], ...]
    *, errors: Sequence[Any], loc_prefix: tuple[str |int, ...]
 ) -> list[dict[str, Any]]:
    updated_loc_errors: list[Any] = [
        {**err, "loc": loc_prefix + err.get("loc", ())} for err in errors
Original file line number	Diff line number	Diff line change
Expand Up		@@ -8,8 +8,11 @@
		from typing import (
		Annotated,
		Any,
		Literal,
		Union,
		cast,
		get_args,
		get_origin,
		)

		from fastapi._compat import lenient_issubclass, shared
Expand All		@@ -32,7 +35,6 @@
		from pydantic_core.core_schema import (
		with_info_plain_validator_function as with_info_plain_validator_function,
		)
		from typing_extensions import Literal, get_args, get_origin

		RequiredParam = PydanticUndefined
		Undefined = PydanticUndefined
Expand DownExpand Up		@@ -83,22 +85,22 @@ class ModelField:
		field_info: FieldInfo
		name: str
		mode: Literal["validation", "serialization"] = "validation"
		config:Union[ConfigDict,None] = None
		config: ConfigDict \|None = None

		@property
		def alias(self) -> str:
		a = self.field_info.alias
		return a if a is not None else self.name

		@property
		def validation_alias(self) ->Union[str,None]:
		def validation_alias(self) -> str \|None:
		va = self.field_info.validation_alias
		if isinstance(va, str) and va:
		return va
		return None

		@property
		def serialization_alias(self) ->Union[str,None]:
		def serialization_alias(self) -> str \|None:
		sa = self.field_info.serialization_alias
		return sa or None

Expand DownExpand Up		@@ -143,7 +145,7 @@ def validate(
		value: Any,
		values: dict[str, Any] = {}, # noqa: B006
		*,
		loc: tuple[Union[int,str], ...] = (),
		loc: tuple[int \|str, ...] = (),
		) -> tuple[Any, list[dict[str, Any]]]:
		try:
		return (
Expand All		@@ -160,8 +162,8 @@ def serialize(
		value: Any,
		*,
		mode: Literal["json", "python"] = "json",
		include:Union[IncEx,None] = None,
		exclude:Union[IncEx,None] = None,
		include: IncEx \|None = None,
		exclude: IncEx \|None = None,
		by_alias: bool = True,
		exclude_unset: bool = False,
		exclude_defaults: bool = False,
Expand DownExpand Up		@@ -202,7 +204,7 @@ def get_schema_from_model_field(
		],
		separate_input_output_schemas: bool = True,
		) -> dict[str, Any]:
		override_mode:Union[Literal["validation"],None] = (
		override_mode: Literal["validation"] \|None = (
		None
		if (separate_input_output_schemas or _has_computed_fields(field))
		else "validation"
Expand DownExpand Up		@@ -318,7 +320,7 @@ def serialize_sequence_value(*, field: ModelField, value: Any) -> Sequence[Any]:
		return shared.sequence_annotation_to_type[origin_type](value) # type: ignore[no-any-return,index]


		def get_missing_field_error(loc: tuple[Union[int,str], ...]) -> dict[str, Any]:
		def get_missing_field_error(loc: tuple[int \|str, ...]) -> dict[str, Any]:
		error = ValidationError.from_exception_data(
		"Field required", [{"type": "missing", "loc": loc, "input": {}}]
		).errors(include_url=False)[0]
Expand DownExpand Up		@@ -360,7 +362,7 @@ def get_cached_model_fields(model: type[BaseModel]) -> list[ModelField]:
		# Duplicate of several schema functions from Pydantic v1 to make them compatible with
		# Pydantic v2 and allow mixing the models

		TypeModelOrEnum =Union[type["BaseModel"],type[Enum]]
		TypeModelOrEnum = type["BaseModel"] \|type[Enum]
		TypeModelSet = set[TypeModelOrEnum]


Expand All		@@ -377,7 +379,7 @@ def get_model_name_map(unique_models: TypeModelSet) -> dict[TypeModelOrEnum, str


		def get_flat_models_from_model(
		model: type["BaseModel"], known_models:Union[TypeModelSet,None] = None
		model: type["BaseModel"], known_models: TypeModelSet \|None = None
		) -> TypeModelSet:
		known_models = known_models or set()
		fields = get_model_fields(model)
Expand DownExpand Up		@@ -426,7 +428,7 @@ def get_flat_models_from_fields(


		def _regenerate_error_with_loc(
		*, errors: Sequence[Any], loc_prefix: tuple[Union[str,int], ...]
		*, errors: Sequence[Any], loc_prefix: tuple[str \|int, ...]
		) -> list[dict[str, Any]]:
		updated_loc_errors: list[Any] = [
		{**err, "loc": loc_prefix + err.get("loc", ())} for err in errors
Expand Down