fix: Support pydantic examples in nested type annotations

polyfactory/factories/pydantic_factory.py

@@ -713,11 +713,29 @@ def get_field_value_coverage(
         if cls.is_ignored_type(field_meta.annotation):
             return
 
+        field_meta = cast("PydanticFieldMeta", field_meta)
         if cls.__use_examples__:
-            examples = getattr(field_meta, "examples", None) or []
-            if len(examples) > 0:
-                yield CoverageContainer(examples)
-                return
+
+            def examples_coverage(field_meta: PydanticFieldMeta) -> Iterable[Any]:
+                examples = field_meta.examples or []
+                if len(examples) > 0:
+                    yield CoverageContainer(examples)
+                    return
+                if field_meta.children:
+                    # NoneType children aren't included in field_meta.children,
+                    # so to ensure that they are covered we need to check for them explicitly
+                    if NoneType in field_meta.type_args:
+                        yield None
+                    for child in field_meta.children:
+                        child = cast("PydanticFieldMeta", child)
+                        yield from examples_coverage(child)
+                    return
+                yield from super(ModelFactory, cls).get_field_value_coverage(
+                    field_meta, field_build_parameters, build_context
+                )
+
+            yield from examples_coverage(field_meta)
+            return
 
         yield from super().get_field_value_coverage(field_meta, field_build_parameters, build_context)
 

tests/test_pydantic_factory.py

@@ -308,6 +308,41 @@ class FooFactory(ModelFactory[Foo]):
     assert {instance.number for instance in instances} == set(example_numbers)
 
 
+@pytest.mark.skipif(_IS_PYDANTIC_V1, reason="Pydantic 1 doesn't support examples")
+def test_factory_use_examples_coverage_when_examples_in_annotations() -> None:
+    class TopLevel(BaseModel):
+        f: Annotated[int, Field(examples=[1, 2, 3, 4])]
+
+    class WithOptional(BaseModel):
+        f: Optional[Annotated[int, Field(examples=[1, 2, 3, 4])]]
+
+    class OrNone(BaseModel):
+        f: Union[Annotated[int, Field(examples=[1, 2, 3, 4])], None]
+
+    class ExamplesInBothSubtypes(BaseModel):
+        f: Union[Annotated[int, Field(examples=[1, 2])], Annotated[int, Field(examples=[3, 4])], None]
+
+    class OuterMostExampleIsRespected(BaseModel):
+        f: Annotated[
+            Union[Annotated[int, Field(examples=[1, 2])], Annotated[int, Field(examples=[3, 4])], None],
+            Field(examples=[6, 7, 8, 9]),
+        ]
+
+    for cls, expected in (
+        (TopLevel, [1, 2, 3, 4]),
+        (WithOptional, [1, 2, 3, 4, None]),
+        (OrNone, [1, 2, 3, 4, None]),
+        (ExamplesInBothSubtypes, [1, 2, 3, 4, None]),
+        (OuterMostExampleIsRespected, [6, 7, 8, 9]),
+    ):
+
+        class ClsFactory(ModelFactory[cls]):  # type: ignore[valid-type]
+            __use_examples__ = True
+
+        instances = list(ClsFactory.coverage())
+        assert {instance.f for instance in instances} == set(expected)  # type: ignore[attr-defined]
+
+
 def test_factory_use_construct_nested() -> None:
     class Child(BaseModel):
         a: int = Field(ge=0)