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Add schema version detection and feature flags
1 parent 58e73ed commit b1d78c6

4 files changed

Lines changed: 477 additions & 0 deletions

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‎src/datamodel_code_generator/__init__.py‎

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@@ -43,12 +43,15 @@
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GraphQLScope,
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InputFileType,
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InputModelRefStrategy,
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JsonSchemaVersion,
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ModuleSplitMode,
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NamingStrategy,
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OpenAPIScope,
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OpenAPIVersion,
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ReadOnlyWriteOnlyModelType,
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ReuseScope,
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TargetPydanticVersion,
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VersionMode,
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)
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from datamodel_code_generator.format import (
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DEFAULT_FORMATTERS,
@@ -930,6 +933,8 @@ def infer_input_type(text: str) -> InputFileType:
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_LAZY_IMPORTS = {
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"clear_dynamic_models_cache": "datamodel_code_generator.dynamic",
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"detect_jsonschema_version": "datamodel_code_generator.parser.schema_version",
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"detect_openapi_version": "datamodel_code_generator.parser.schema_version",
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"generate_dynamic_models": "datamodel_code_generator.dynamic",
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}
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@@ -966,17 +971,22 @@ def __getattr__(name: str) -> Any:
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"InputModelRefStrategy",
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"InvalidClassNameError",
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"InvalidFileFormatError",
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"JsonSchemaVersion",
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"LiteralType",
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"ModuleSplitMode",
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"NamingStrategy",
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"OpenAPIScope",
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"OpenAPIVersion",
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"PythonVersion",
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"PythonVersionMin",
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"ReadOnlyWriteOnlyModelType",
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"ReuseScope",
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"SchemaParseError",
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"TargetPydanticVersion",
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"VersionMode",
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"clear_dynamic_models_cache", # noqa: F822
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"detect_jsonschema_version", # noqa: F822
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"detect_openapi_version", # noqa: F822
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"generate",
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"generate_dynamic_models", # noqa: F822
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]

‎src/datamodel_code_generator/enums.py‎

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@@ -240,6 +240,42 @@ class StrictTypes(Enum):
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bool = "bool"
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class JsonSchemaVersion(Enum):
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"""JSON Schema draft versions.
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Auto: Auto-detect from $schema field or heuristics (default).
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"""
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Draft4 = "draft-04"
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Draft6 = "draft-06"
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Draft7 = "draft-07"
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Draft201909 = "2019-09"
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Draft202012 = "2020-12"
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Auto = "auto"
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class OpenAPIVersion(Enum):
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"""OpenAPI specification versions.
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Auto: Auto-detect from openapi field (default).
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"""
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V30 = "3.0"
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V31 = "3.1"
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Auto = "auto"
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class VersionMode(Enum):
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"""Schema version validation mode.
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Lenient: Accept all features regardless of declared version (default).
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Strict: Warn on features outside declared/detected version.
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"""
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Lenient = "lenient"
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Strict = "strict"
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__all__ = [
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"DEFAULT_SHARED_MODULE_NAME",
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"MAX_VERSION",
@@ -256,12 +292,15 @@ class StrictTypes(Enum):
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"GraphQLScope",
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"InputFileType",
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"InputModelRefStrategy",
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"JsonSchemaVersion",
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"ModuleSplitMode",
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"NamingStrategy",
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"OpenAPIScope",
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"OpenAPIVersion",
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"ReadOnlyWriteOnlyModelType",
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"ReuseScope",
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"StrictTypes",
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"TargetPydanticVersion",
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"UnionMode",
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"VersionMode",
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]

‎src/datamodel_code_generator/parser/schema_version.py‎

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"""Schema version features and detection utilities.
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Provides SchemaFeatures classes for version-dependent feature flags
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and utility functions for detecting schema versions.
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"""
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from __future__ import annotations
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from dataclasses import dataclass
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from typing import Any, TypeVar
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from datamodel_code_generator.enums import JsonSchemaVersion, OpenAPIVersion
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@dataclass(frozen=True)
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class JsonSchemaFeatures:
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"""Feature flags for JSON Schema versions.
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This is the base class for schema features. OpenAPISchemaFeatures
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extends this to add OpenAPI-specific features.
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Attributes:
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null_in_type_array: Draft 2020-12 allows null in type arrays.
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defs_not_definitions: Draft 2019-09+ uses $defs instead of definitions.
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prefix_items: Draft 2020-12 uses prefixItems instead of items array.
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boolean_schemas: Draft 6+ allows boolean values as schemas.
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id_field: The field name for schema ID ("id" for Draft 4, "$id" for Draft 6+).
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definitions_key: The key for definitions ("definitions" or "$defs").
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"""
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null_in_type_array: bool
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defs_not_definitions: bool
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prefix_items: bool
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boolean_schemas: bool
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id_field: str
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definitions_key: str
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@classmethod
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def from_version(cls, version: JsonSchemaVersion) -> JsonSchemaFeatures:
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"""Create JsonSchemaFeatures from a JSON Schema version."""
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if version == JsonSchemaVersion.Draft4:
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return cls(
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null_in_type_array=False,
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defs_not_definitions=False,
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prefix_items=False,
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boolean_schemas=False,
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id_field="id",
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definitions_key="definitions",
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)
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if version in {JsonSchemaVersion.Draft6, JsonSchemaVersion.Draft7}:
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return cls(
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null_in_type_array=False,
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defs_not_definitions=False,
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prefix_items=False,
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boolean_schemas=True,
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id_field="$id",
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definitions_key="definitions",
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)
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if version == JsonSchemaVersion.Draft201909:
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return cls(
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null_in_type_array=False,
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defs_not_definitions=True,
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prefix_items=False,
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boolean_schemas=True,
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id_field="$id",
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definitions_key="$defs",
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)
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# Draft 2020-12 or Auto (default to latest features in lenient mode)
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return cls(
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null_in_type_array=True,
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defs_not_definitions=True,
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prefix_items=True,
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boolean_schemas=True,
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id_field="$id",
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definitions_key="$defs",
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)
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@dataclass(frozen=True)
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class OpenAPISchemaFeatures(JsonSchemaFeatures):
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"""Feature flags for OpenAPI versions.
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Extends JsonSchemaFeatures with OpenAPI-specific features.
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Attributes:
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nullable_keyword: OpenAPI 3.0 uses nullable: true (deprecated in 3.1).
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discriminator_support: All OpenAPI versions support discriminator.
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"""
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nullable_keyword: bool
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discriminator_support: bool
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@classmethod
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def from_openapi_version(cls, version: OpenAPIVersion) -> OpenAPISchemaFeatures:
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"""Create OpenAPISchemaFeatures from an OpenAPI version."""
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if version == OpenAPIVersion.V30:
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# OpenAPI 3.0 does not support boolean schemas (only 3.1+ does)
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return cls(
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null_in_type_array=False,
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defs_not_definitions=False,
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prefix_items=False,
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boolean_schemas=False,
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id_field="$id",
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definitions_key="definitions",
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nullable_keyword=True,
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discriminator_support=True,
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)
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# OpenAPI 3.1 or Auto (default to latest features in lenient mode)
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return cls(
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null_in_type_array=True,
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defs_not_definitions=True,
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prefix_items=True,
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boolean_schemas=True,
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id_field="$id",
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definitions_key="$defs",
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nullable_keyword=False,
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discriminator_support=True,
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)
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# Type variable for SchemaFeatures subclasses
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SchemaFeaturesT = TypeVar("SchemaFeaturesT", bound=JsonSchemaFeatures)
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def detect_jsonschema_version(data: dict[str, Any]) -> JsonSchemaVersion: # noqa: PLR0911
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"""Detect JSON Schema version from $schema field or heuristics.
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Detection priority:
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1. $schema field explicit declaration
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2. Heuristics ($defs vs definitions, etc.)
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3. Fallback: Draft7 (most widely used)
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Note: In Lenient mode, detection result is only used for optimization hints.
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In Strict mode, detection result is used to warn on version violations.
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Args:
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data: The schema dictionary to analyze.
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Returns:
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The detected JSON Schema version.
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"""
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schema_url = data.get("$schema", "")
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if isinstance(schema_url, str):
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if "draft-04" in schema_url:
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return JsonSchemaVersion.Draft4
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if "draft-06" in schema_url:
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return JsonSchemaVersion.Draft6
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if "draft-07" in schema_url:
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return JsonSchemaVersion.Draft7
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if "2019-09" in schema_url:
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return JsonSchemaVersion.Draft201909
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if "2020-12" in schema_url:
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return JsonSchemaVersion.Draft202012
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# Heuristic detection (when $schema is missing)
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if "$defs" in data:
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# $defs was introduced in Draft 2019-09
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# prefixItems is specific to Draft 2020-12
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if "prefixItems" in data:
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return JsonSchemaVersion.Draft202012
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return JsonSchemaVersion.Draft201909
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if "definitions" in data:
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return JsonSchemaVersion.Draft7
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# Fallback: Draft7 is the most widely used
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return JsonSchemaVersion.Draft7
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def detect_openapi_version(data: dict[str, Any]) -> OpenAPIVersion:
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"""Detect OpenAPI version from openapi field.
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Args:
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data: The schema dictionary to analyze.
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Returns:
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The detected OpenAPI version.
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"""
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version = data.get("openapi", "")
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if isinstance(version, str):
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if version.startswith("3.1"):
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return OpenAPIVersion.V31
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if version.startswith("3.0"):
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return OpenAPIVersion.V30
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# Fallback: 3.1 (latest, best JSON Schema compatibility)
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return OpenAPIVersion.V31
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__all__ = [
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"JsonSchemaFeatures",
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"OpenAPISchemaFeatures",
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"SchemaFeaturesT",
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"detect_jsonschema_version",
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"detect_openapi_version",
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]

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