Fix ModelConverter when impl is not callable

sqladmin/forms.py

@@ -77,7 +77,7 @@ def __init__(self) -> None:
         super().__init__()
         self._register_converters()
 
-    def _register_converters(self):
+    def _register_converters(self) -> None:
         converters = {}
 
         for name in dir(self):
@@ -94,13 +94,12 @@ async def _prepare_kwargs(
         engine: Union[Engine, AsyncEngine],
         field_args: Dict[str, Any] = None,
         label: Optional[str] = None,
-    ) -> Dict[str, Any]:
+    ) -> Optional[Dict[str, Any]]:
         if field_args:
             kwargs = field_args.copy()
         else:
             kwargs = {}
 
-        kwargs: Dict[str, Any]
         kwargs.setdefault("label", label)
         kwargs.setdefault("validators", [])
         kwargs.setdefault("filters", [])
@@ -115,7 +114,7 @@ async def _prepare_kwargs(
             column = prop.columns[0]
 
             if column.primary_key or column.foreign_keys:
-                return
+                return None
 
             default = getattr(column, "default", None)
 
@@ -198,8 +197,13 @@ def get_converter(
 
             # Support for custom types like SQLModel which inherit TypeDecorator
             if hasattr(col_type, "impl"):
-                if col_type.impl.__name__ in self._converters:  # type: ignore
-                    return self._converters[col_type.impl.__name__]  # type: ignore
+                if callable(col_type.impl):  # type: ignore
+                    impl = col_type.impl  # type: ignore
+                else:
+                    impl = col_type.impl.__class__  # type: ignore
+
+                if impl.__name__ in self._converters:
+                    return self._converters[impl.__name__]
 
         raise NoConverterFound(  # pragma: nocover
             f"Could not find field converter for column {column.name} ({types[0]!r})."

tests/test_forms.py

@@ -12,6 +12,7 @@
     Numeric,
     String,
     Text,
+    TypeDecorator,
 )
 from sqlalchemy.dialects.postgresql import INET, MACADDR, UUID
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -178,3 +179,31 @@ class UserAdmin(ModelAdmin, model=User):
     assert isinstance(form, MyForm)
     assert len(form._fields) == 1
     assert "foo" in form._fields
+
+
+async def test_form_converter_when_impl_is_callable() -> None:
+    class MyType(TypeDecorator):
+        impl = String
+
+    class CustomModel(Base):
+        __tablename__ = "impl_callable"
+
+        id = Column(Integer, primary_key=True)
+        custom = Column(MyType)
+
+    Form = await get_model_form(model=CustomModel, engine=engine)
+    assert "custom" in Form()._fields
+
+
+async def test_form_converter_when_impl_not_callable() -> None:
+    class MyType(TypeDecorator):
+        impl = String(length=100)
+
+    class CustomModel(Base):
+        __tablename__ = "impl_non_callable"
+
+        id = Column(Integer, primary_key=True)
+        custom = Column(MyType)
+
+    Form = await get_model_form(model=CustomModel, engine=engine)
+    assert "custom" in Form()._fields