Merge "establish mypy / typing approach for v2.0" into main

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/sqlalchemy/util/langhelpers.py b/lib/sqlalchemy/util/langhelpers.py
index 9401c249f..ed879894d 100644
--- a/lib/sqlalchemy/util/langhelpers.py
+++ b/lib/sqlalchemy/util/langhelpers.py
@@ -30,6 +30,7 @@ from typing import FrozenSet
 from typing import Generic
 from typing import Iterator
 from typing import List
+from typing import Mapping
 from typing import Optional
 from typing import overload
 from typing import Sequence
@@ -54,6 +55,30 @@ _HP = TypeVar("_HP", bound="hybridproperty")
 _HM = TypeVar("_HM", bound="hybridmethod")
 
 
+if compat.py310:
+
+    def get_annotations(obj: Any) -> Mapping[str, Any]:
+        return inspect.get_annotations(obj)
+
+else:
+
+    def get_annotations(obj: Any) -> Mapping[str, Any]:
+        # it's been observed that cls.__annotations__ can be non present.
+        # it's not clear what causes this, running under tox py37/38 it
+        # happens, running straight pytest it doesnt
+
+        # https://docs.python.org/3/howto/annotations.html#annotations-howto
+        if isinstance(obj, type):
+            ann = obj.__dict__.get("__annotations__", None)
+        else:
+            ann = getattr(obj, "__annotations__", None)
+
+        if ann is None:
+            return _collections.EMPTY_DICT
+        else:
+            return cast("Mapping[str, Any]", ann)
+
+
 def md5_hex(x: Any) -> str:
     x = x.encode("utf-8")
     m = hashlib.md5()