fixed bug with type_safe decorator handling of forward refs

Author: DinisCruz

osbot_utils/decorators/methods/cache_on_self.py

@@ -1,8 +1,6 @@
-import inspect
 from functools                                         import wraps
-from typing import Any, Callable, TypeVar, Dict
-from weakref import WeakKeyDictionary
-
+from typing                                            import Any, Callable, TypeVar, Dict
+from weakref                                           import WeakKeyDictionary
 from osbot_utils.helpers.cache_on_self.Cache_On_Self   import Cache_On_Self
 
 

osbot_utils/type_safe/Type_Safe__Base.py

@@ -11,8 +11,15 @@ class Type_Safe__Base:
     def is_instance_of_type(self, item, expected_type):
         if expected_type is Any:
             return True
-        if isinstance(expected_type, ForwardRef):               # todo: add support for ForwardRef
+        if isinstance(expected_type, str):
+            if type(item).__name__ == expected_type:                                                                # happens in ForwardRefs
+                return True
+            else:
+                raise TypeError(f"Expected type '{expected_type}' but got instance of '{type(item).__name__}'.")    # Doesn't match - unresolvable forward reference
+
+        if isinstance(expected_type, ForwardRef):                    # todo: add support for ForwardRef | todo: see the side effects of this 'return true'
             return True
+
         origin = type_safe_cache.get_origin(expected_type)
         args   = get_args(expected_type)
 

tests/unit/type_safe/type_safe_core/decorators/test__decorator__type_safe__bugs.py

@@ -1,4 +1,3 @@
-import re
 import pytest
 from typing                                                                    import List, Dict, Callable
 from unittest                                                                  import TestCase
@@ -8,14 +7,6 @@
 
 class test__decorator__type_safe__bugs(TestCase):
 
-    def test__bug__type_safe__return_value__not_works__with_forward_refs(self):
-        class An_Class(Type_Safe):
-            @type_safe
-            def return_self(self) ->'An_Class':
-                return self
-        error_message = "Function 'test__decorator__type_safe__bugs.test__bug__type_safe__return_value__not_works__with_forward_refs.<locals>.An_Class.return_self' return type validation failed: isinstance() arg 2 must be a type, a tuple of types, or a union"
-        with pytest.raises(TypeError, match=re.escape(error_message)):
-            An_Class().return_self()
 
     def test__bug__type_safe__list_callable_with_signatures(self):
 

tests/unit/type_safe/type_safe_core/decorators/test__decorator__type_safe__regression.py

@@ -488,3 +488,38 @@ def an_method(texts : Dict[Safe_Str, Safe_UInt]):
         assert an_method(texts=texts_1) == texts_2
         assert an_method(texts=texts_1) == texts_3
         assert an_method(texts=texts_1) == texts_4
+
+    def test__regression__type_safe__return_value__not_works__with__bad__forward_refs(self):
+        import re
+
+        class An_Class(Type_Safe):
+            @type_safe
+            def an_method(self) -> 'An_Class2':
+                return self
+
+        error_message = ("Function 'test_decorator__type_safe__regression.test__regression__type_safe__return_value__not_works__with__bad__forward_refs."
+                         "<locals>.An_Class.an_method' return type validation failed: "                         
+                         "Expected type 'An_Class2' but got instance of 'An_Class'.")
+
+        with pytest.raises(TypeError, match=re.escape(error_message)):
+            An_Class().an_method()
+
+    def test__regression__type_safe__return_value__not_works__with_differnt__forward_refs(self):
+        class An_Class_2(Type_Safe):
+            pass
+        class An_Class_1(Type_Safe):
+            @type_safe
+            def an_method(self) -> 'An_Class_2':
+                return An_Class_2()
+
+        assert type(An_Class_1().an_method()) is An_Class_2         # FIXED: this used to fail before fix
+
+    def test__regression__type_safe__return_value__not_works__with_forward_refs(self):
+        class An_Class(Type_Safe):
+            @type_safe
+            def return_self(self) -> 'An_Class':
+                return self
+        # error_message = "Function 'test__decorator__type_safe__bugs.test__bug__type_safe__return_value__not_works__with_forward_refs.<locals>.An_Class.return_self' return type validation failed: isinstance() arg 2 must be a type, a tuple of types, or a union"
+        # with pytest.raises(TypeError, match=re.escape(error_message)):
+        #     An_Class().return_self()              # BUG
+        assert type(An_Class().return_self()) is An_Class           # FIXED