Fix ForwardRef collection bug

docs/examples/forward_ref.py

@@ -4,12 +4,14 @@
 Foo = ForwardRef('Foo')
 
 class Foo(BaseModel):
-    a: int = 123
-    b: Foo = None
+    a: int = None
+    b: Dict[str, FooType] = {}
+    c: List[Foo] = []
+
 
 Foo.update_forward_refs()
 
 print(Foo())
-#> Foo a=123 b=None
-print(Foo(b={'a': '321'}))
-#> Foo a=123 b=<Foo a=321 b=None>
+#> Foo a=123 b={} c=[]
+print(Foo(b={'bar': {'a': '321'}}, c=[{'a': 345}]))
+#> Foo a=123 b={'bar': <Foo a=321 b={} c=[]>} c=[<Foo a=345 b={} c=[]>]

pydantic/validators.py

@@ -10,7 +10,7 @@
 
 from . import errors
 from .datetime_parse import parse_date, parse_datetime, parse_duration, parse_time
-from .utils import AnyCallable, AnyType, change_exception, display_as_type, is_callable_type, sequence_like
+from .utils import AnyCallable, AnyType, ForwardRef, change_exception, display_as_type, is_callable_type, sequence_like
 
 if TYPE_CHECKING:  # pragma: no cover
     from .fields import Field
@@ -357,7 +357,7 @@ def pattern_validator(v: Any) -> Pattern[str]:
 
 
 def find_validators(type_: AnyType, arbitrary_types_allowed: bool = False) -> List[AnyCallable]:
-    if type_ is Any:
+    if type_ is Any or type(type_) == ForwardRef:
         return []
     if type_ is Pattern:
         return pattern_validators

tests/test_py37.py

@@ -5,7 +5,7 @@
 
 import pytest
 
-from pydantic import ConfigError
+from pydantic import ConfigError, ValidationError
 
 skip_not_37 = pytest.mark.skipif(sys.version_info < (3, 7), reason='testing >= 3.7 behaviour only')
 
@@ -83,6 +83,60 @@ class Foo(BaseModel):
     assert module.Foo(b={'a': '321'}).dict() == {'a': 123, 'b': {'a': 321, 'b': None}}
 
 
+@skip_not_37
+def test_self_forward_ref_collection(create_module):
+    module = create_module(
+        """
+from typing import ForwardRef, List, Dict
+from pydantic import BaseModel
+
+Foo = ForwardRef('Foo')
+
+class Foo(BaseModel):
+    a: int = 123
+    b: Foo = None
+    c: List[Foo] = []
+    d: Dict[str, Foo] = {}
+
+Foo.update_forward_refs()
+    """
+    )
+
+    assert module.Foo().dict() == {'a': 123, 'b': None, 'c': [], 'd': {}}
+    assert module.Foo(b={'a': '321'}, c=[{'a': 234}], d={'bar': {'a': 345}}).dict() == {
+        'a': 123,
+        'b': {'a': 321, 'b': None, 'c': [], 'd': {}},
+        'c': [{'a': 234, 'b': None, 'c': [], 'd': {}}],
+        'd': {'bar': {'a': 345, 'b': None, 'c': [], 'd': {}}},
+    }
+
+
+@skip_not_37
+def test_self_forward_ref_validation(create_module):
+    module = create_module(
+        """
+from typing import ForwardRef, List, Dict
+from pydantic import BaseModel
+
+Foo = ForwardRef('Foo')
+
+class Foo(BaseModel):
+    a: int = 123
+    b: Foo = None
+    c: List[Foo] = []
+    d: Dict[str, Foo] = {}
+
+Foo.update_forward_refs()
+    """
+    )
+
+    with pytest.raises(ValidationError) as exc_info:
+        module.Foo(b={'a': '321'}, c=[{'b': 234}], d={'bar': {'a': 345}})
+    assert exc_info.value.errors() == [
+        {'loc': ('c', 0, 'b'), 'msg': 'value is not a valid dict', 'type': 'type_error.dict'}
+    ]
+
+
 @skip_not_37
 def test_self_forward_ref_local(create_module):
     module = create_module(