Resolve ForwardRef on Field.outer_type_ (#4249)

* Add tests checking Field.outer_type_ ForwardRefs

* Update root ForwardRefs in field.outer_type_

* fix strings

* Add changes file

changes/4249-JacobHayes.md

@@ -0,0 +1 @@
+Update `ForwardRef`s in `Field.outer_type_`

pydantic/typing.py

@@ -507,8 +507,14 @@ def update_field_forward_refs(field: 'ModelField', globalns: Any, localns: Any)
     """
     Try to update ForwardRefs on fields based on this ModelField, globalns and localns.
     """
+    prepare = False
     if field.type_.__class__ == ForwardRef:
+        prepare = True
         field.type_ = evaluate_forwardref(field.type_, globalns, localns or None)
+    if field.outer_type_.__class__ == ForwardRef:
+        prepare = True
+        field.outer_type_ = evaluate_forwardref(field.outer_type_, globalns, localns or None)
+    if prepare:
         field.prepare()
 
     if field.sub_fields:

tests/test_forward_ref.py

@@ -1,5 +1,5 @@
 import sys
-from typing import Optional, Tuple
+from typing import Dict, List, Optional, Tuple
 
 import pytest
 
@@ -131,15 +131,12 @@ def module():
         from typing import Dict, List
 
         from pydantic import BaseModel
-        from pydantic.typing import ForwardRef
-
-        Foo = ForwardRef('Foo')
 
         class Foo(BaseModel):
             a: int = 123
-            b: Foo = None
-            c: List[Foo] = []
-            d: Dict[str, Foo] = {}
+            b: 'Foo' = None
+            c: 'List[Foo]' = []
+            d: 'Dict[str, Foo]' = {}
 
         Foo.update_forward_refs()
 
@@ -157,6 +154,14 @@ class Foo(BaseModel):
         {'loc': ('c', 0, 'b'), 'msg': 'value is not a valid dict', 'type': 'type_error.dict'}
     ]
 
+    assert module.Foo.__fields__['a'].type_ is int
+    assert module.Foo.__fields__['b'].type_ is module.Foo
+    assert module.Foo.__fields__['b'].outer_type_ is module.Foo
+    assert module.Foo.__fields__['c'].type_ is module.Foo
+    assert module.Foo.__fields__['c'].outer_type_ == List[module.Foo]
+    assert module.Foo.__fields__['d'].type_ is module.Foo
+    assert module.Foo.__fields__['d'].outer_type_ == Dict[str, module.Foo]
+
 
 def test_self_forward_ref_local(create_module):
     @create_module