Fix failures when resolving forward references from dataclass parameter types

CHANGELOG.rst

@@ -31,6 +31,8 @@ Fixed
   <https://github.com/omni-us/jsonargparse/pull/603>`__).
 - Custom instantiators not working for nested dependency injection (`#608
   <https://github.com/omni-us/jsonargparse/pull/608>`__).
+- Failure when resolving forward references from dataclass parameter types
+  (`#611 <https://github.com/omni-us/jsonargparse/pull/611>`__).
 
 Changed
 ^^^^^^^

jsonargparse/_postponed_annotations.py

@@ -259,8 +259,20 @@ def type_requires_eval(typehint):
     return isinstance(typehint, (str, ForwardRef))
 
 
-def get_types(obj: Any, logger: Optional[logging.Logger] = None) -> dict:
+def get_global_vars(obj: Any, logger: Optional[logging.Logger]) -> dict:
     global_vars = vars(import_module(obj.__module__))
+    try:
+        module_source = inspect.getsource(sys.modules[obj.__module__]) if obj.__module__ in sys.modules else ""
+        if "TYPE_CHECKING" in module_source:
+            TypeCheckingVisitor().update_aliases(module_source, obj.__module__, global_vars, logger)
+    except Exception as ex:
+        if logger:
+            logger.debug(f"Failed to update aliases for TYPE_CHECKING blocks in {obj.__module__}", exc_info=ex)
+    return global_vars
+
+
+def get_types(obj: Any, logger: Optional[logging.Logger] = None) -> dict:
+    global_vars = get_global_vars(obj, logger)
     try:
         types = get_type_hints(obj, global_vars)
     except Exception as ex1:
@@ -288,10 +300,6 @@ def get_types(obj: Any, logger: Optional[logging.Logger] = None) -> dict:
         ex = types
         types = {}
 
-    module_source = inspect.getsource(sys.modules[obj.__module__]) if obj.__module__ in sys.modules else ""
-    if "TYPE_CHECKING" in module_source:
-        TypeCheckingVisitor().update_aliases(module_source, obj.__module__, aliases, logger)
-
     if isinstance(node, ast.FunctionDef):
         arg_asts = [(a.arg, a.annotation) for a in node.args.args + node.args.kwonlyargs]
     else:

jsonargparse_tests/test_postponed_annotations.py

@@ -256,7 +256,7 @@ def function_type_checking_list(p1: List[Union["TypeCheckingClass1", TypeCheckin
 def test_get_types_type_checking_list():
     types = get_types(function_type_checking_list)
     assert list(types.keys()) == ["p1"]
-    lst = "typing.List" if sys.version_info < (3, 10) else "list"
+    lst = "typing.List"
     assert str(types["p1"]) == f"{lst}[typing.Union[{__name__}.TypeCheckingClass1, {__name__}.TypeCheckingClass2]]"
 
 
@@ -267,7 +267,7 @@ def function_type_checking_tuple(p1: Tuple[TypeCheckingClass1, "TypeCheckingClas
 def test_get_types_type_checking_tuple():
     types = get_types(function_type_checking_tuple)
     assert list(types.keys()) == ["p1"]
-    tpl = "typing.Tuple" if sys.version_info < (3, 10) else "tuple"
+    tpl = "typing.Tuple"
     assert str(types["p1"]) == f"{tpl}[{__name__}.TypeCheckingClass1, {__name__}.TypeCheckingClass2]"
 
 
@@ -278,7 +278,7 @@ def function_type_checking_type(p1: Type["TypeCheckingClass2"]):
 def test_get_types_type_checking_type():
     types = get_types(function_type_checking_type)
     assert list(types.keys()) == ["p1"]
-    tpl = "typing.Type" if sys.version_info < (3, 10) else "type"
+    tpl = "typing.Type"
     assert str(types["p1"]) == f"{tpl}[{__name__}.TypeCheckingClass2]"
 
 
@@ -289,7 +289,7 @@ def function_type_checking_dict(p1: Dict[str, Union[TypeCheckingClass1, "TypeChe
 def test_get_types_type_checking_dict():
     types = get_types(function_type_checking_dict)
     assert list(types.keys()) == ["p1"]
-    dct = "typing.Dict" if sys.version_info < (3, 10) else "dict"
+    dct = "typing.Dict"
     assert str(types["p1"]) == f"{dct}[str, typing.Union[{__name__}.TypeCheckingClass1, {__name__}.TypeCheckingClass2]]"
 
 
@@ -305,6 +305,18 @@ def test_get_types_type_checking_undefined_forward_ref(logger):
     assert "NameError: Name 'Undefined' is not defined" in logs.getvalue()
 
 
+@dataclasses.dataclass
+class DataclassForwardRef:
+    p1: "int"
+    p2: Optional["xml.dom.Node"] = None
+
+
+@pytest.mark.skipif(sys.version_info < (3, 9), reason="not working in python 3.8")
+def test_get_types_type_checking_dataclass_init_forward_ref():
+    types = get_types(DataclassForwardRef.__init__)
+    assert types == {"p1": int, "p2": Optional[xml.dom.Node], "return": type(None)}
+
+
 def function_source_unavailable(p1: List["TypeCheckingClass1"]):
     return p1