Ignore all dunders when checking attributes in `sqlalchemy.util.langh…

…elpers.TypingOnly`

Fixed an internal class that was testing for unexpected attributes to work
correctly under upcoming Python 3.13.   Pull request courtesy Edgar
Ramírez-Mondragón.

Fixes: #11334
Closes: #11335
Pull-request: #11335
Pull-request-sha: babd703

Change-Id: Ia2e7392c9403e25266c7d30b987b577f49d008c0
(cherry picked from commit eb118e2)

doc/build/changelog/unreleased_20/11334.rst

@@ -0,0 +1,7 @@
+.. change::
+    :tags: bug, installation
+    :tickets: 11334
+
+    Fixed an internal class that was testing for unexpected attributes to work
+    correctly under upcoming Python 3.13.   Pull request courtesy Edgar
+    Ramírez-Mondragón.

lib/sqlalchemy/util/langhelpers.py

@@ -1958,6 +1958,9 @@ def attrsetter(attrname):
     return env["set"]
 
 
+_dunders = re.compile("^__.+__$")
+
+
 class TypingOnly:
     """A mixin class that marks a class as 'typing only', meaning it has
     absolutely no methods, attributes, or runtime functionality whatsoever.
@@ -1968,15 +1971,9 @@ class TypingOnly:
 
     def __init_subclass__(cls) -> None:
         if TypingOnly in cls.__bases__:
-            remaining = set(cls.__dict__).difference(
-                {
-                    "__module__",
-                    "__doc__",
-                    "__slots__",
-                    "__orig_bases__",
-                    "__annotations__",
-                }
-            )
+            remaining = {
+                name for name in cls.__dict__ if not _dunders.match(name)
+            }
             if remaining:
                 raise AssertionError(
                     f"Class {cls} directly inherits TypingOnly but has "