📝 Refactor type alias handling to improve compatibility with Python 3.10 and enhance type resolution logic

Author: stickm4n

sqlmodel/_compat.py

@@ -1,6 +1,5 @@
 import sys
 import types
-import typing
 from contextlib import contextmanager
 from contextvars import ContextVar
 from dataclasses import dataclass
@@ -20,7 +19,6 @@
     Union,
 )
 
-import typing_extensions
 from pydantic import VERSION as P_VERSION
 from pydantic import BaseModel
 from pydantic.fields import FieldInfo
@@ -200,47 +198,10 @@ def is_field_noneable(field: "FieldInfo") -> bool:
             return False
         return False
 
-    def _is_typing_type_instance(annotation: Any, type_name: str) -> bool:
-        check_type = []
-        if hasattr(typing, type_name):
-            check_type.append(getattr(typing, type_name))
-        if hasattr(typing_extensions, type_name):
-            check_type.append(getattr(typing_extensions, type_name))
-
-        return bool(check_type) and isinstance(annotation, tuple(check_type))
-
-    def _is_new_type_instance(annotation: Any) -> bool:
-        if sys.version_info >= (3, 10):
-            return _is_typing_type_instance(annotation, "NewType")
-        else:
-            return hasattr(annotation, "__supertype__")
-
-    def _is_type_var_instance(annotation: Any) -> bool:
-        return _is_typing_type_instance(annotation, "TypeVar")
-
-    def _is_type_alias_type_instance(annotation: Any) -> bool:
-        if sys.version_info[:2] == (3, 10):
-            if type(annotation) is types.GenericAlias:
-                # In Python 3.10, GenericAlias instances are of type TypeAliasType
-                return False
-
-        return _is_typing_type_instance(annotation, "TypeAliasType")
-
     def get_sa_type_from_type_annotation(annotation: Any) -> Any:
         # Resolve Optional fields
         if annotation is None:
             raise ValueError("Missing field type")
-        if _is_type_var_instance(annotation):
-            annotation = annotation.__bound__
-            if not annotation:
-                raise ValueError(
-                    "TypeVars without a bound type cannot be converted to SQLAlchemy types"
-                )
-            # annotations.__constraints__ could be used and defined Union[*constraints], but ORM does not support it
-        elif _is_new_type_instance(annotation):
-            annotation = annotation.__supertype__
-        elif _is_type_alias_type_instance(annotation):
-            annotation = annotation.__value__
         origin = get_origin(annotation)
         if origin is None:
             return annotation

sqlmodel/main.py

@@ -1,6 +1,9 @@
 from __future__ import annotations
 
 import ipaddress
+import sys
+import types
+import typing
 import uuid
 import weakref
 from datetime import date, datetime, time, timedelta
@@ -27,6 +30,7 @@
     overload,
 )
 
+import typing_extensions
 from pydantic import BaseModel, EmailStr
 from pydantic.fields import FieldInfo as PydanticFieldInfo
 from sqlalchemy import (
@@ -519,7 +523,7 @@ def __new__(
             if k in relationships:
                 relationship_annotations[k] = v
             else:
-                pydantic_annotations[k] = v
+                pydantic_annotations[k] = resolve_type_alias(v)
         dict_used = {
             **dict_for_pydantic,
             "__weakref__": None,
@@ -763,6 +767,54 @@ def get_column_from_field(field: Any) -> Column:  # type: ignore
     return Column(sa_type, *args, **kwargs)  # type: ignore
 
 
+def _is_typing_type_instance(annotation: Any, type_name: str) -> bool:
+    check_type = []
+    if hasattr(typing, type_name):
+        check_type.append(getattr(typing, type_name))
+    if hasattr(typing_extensions, type_name):
+        check_type.append(getattr(typing_extensions, type_name))
+
+    return bool(check_type) and isinstance(annotation, tuple(check_type))
+
+
+def _is_new_type_instance(annotation: Any) -> bool:
+    if sys.version_info >= (3, 10):
+        return _is_typing_type_instance(annotation, "NewType")
+    else:
+        return hasattr(annotation, "__supertype__")
+
+
+def _is_type_var_instance(annotation: Any) -> bool:
+    return _is_typing_type_instance(annotation, "TypeVar")
+
+
+def _is_type_alias_type_instance(annotation: Any) -> bool:
+    if sys.version_info[:2] == (3, 10):
+        if type(annotation) is types.GenericAlias:
+            # In Python 3.10, GenericAlias instances are of type TypeAliasType
+            return False
+
+    return _is_typing_type_instance(annotation, "TypeAliasType")
+
+
+def resolve_type_alias(annotation: Any) -> Any:
+    if _is_type_var_instance(annotation):
+        resolution = annotation.__bound__
+        if not annotation:
+            raise ValueError(
+                "TypeVars without a bound type cannot be converted to SQLAlchemy types"
+            )
+        # annotations.__constraints__ could be used and defined Union[*constraints], but ORM does not support it
+    elif _is_new_type_instance(annotation):
+        resolution = annotation.__supertype__
+    elif _is_type_alias_type_instance(annotation):
+        resolution = annotation.__value__
+    else:
+        resolution = annotation
+
+    return resolution
+
+
 class_registry = weakref.WeakValueDictionary()  # type: ignore
 
 default_registry = registry()

tests/test_field_sa_type.py

@@ -5,7 +5,7 @@
 import typing_extensions as te
 from sqlmodel import Field, SQLModel
 
-from tests.conftest import needs_py312, needs_pydanticv2
+from tests.conftest import needs_py312
 
 
 def test_sa_type_typing_1() -> None:
@@ -44,7 +44,6 @@ class Hero(SQLModel, table=True):
 
 
 @needs_py312
-@needs_pydanticv2
 def test_sa_type_typing_5() -> None:
     test_code = dedent("""
     type Type5_t = str
@@ -57,7 +56,6 @@ class Hero(SQLModel, table=True):
 
 
 @needs_py312
-@needs_pydanticv2
 def test_sa_type_typing_6() -> None:
     test_code = dedent("""
     type Type6_t = t.Annotated[str, "Just a comment"]
@@ -131,7 +129,6 @@ class Hero(SQLModel, table=True):
 
 
 @needs_py312
-@needs_pydanticv2
 def test_sa_type_typing_extensions_5() -> None:
     test_code = dedent("""
     type Type5_te = str
@@ -144,7 +141,6 @@ class Hero(SQLModel, table=True):
 
 
 @needs_py312
-@needs_pydanticv2
 def test_sa_type_typing_extensions_6() -> None:
     test_code = dedent("""
     type Type6_te = te.Annotated[str, "Just a comment"]
@@ -156,7 +152,6 @@ class Hero(SQLModel, table=True):
     exec(test_code, globals())
 
 
-@needs_pydanticv2
 def test_sa_type_typing_extensions_7() -> None:
     Type7_te = te.NewType("Type7_te", str)