Vendor inspect.formatannotation

Vendored the ``inspect.formatannotation`` function inside of
``sqlalchemy.util.compat``, which is needed for the vendored version of
``inspect.formatargspec``.  The function is not documented in cPython and
is not guaranteed to be available in future Python versions.

Fixes: #5138
Change-Id: I76bdddc28507fb1b4403f1b718d6f9cc2fb6d93c

1 files changed, 13 insertions, 2 deletions

diff --git a/lib/sqlalchemy/util/compat.py b/lib/sqlalchemy/util/compat.py
index ea9ac0f11..8967955cd 100644
--- a/lib/sqlalchemy/util/compat.py
+++ b/lib/sqlalchemy/util/compat.py
@@ -270,7 +270,18 @@ else:
 
 
 if py35:
-    from inspect import formatannotation
+
+    def _formatannotation(annotation, base_module=None):
+        """vendored from python 3.7
+        """
+
+        if getattr(annotation, "__module__", None) == "typing":
+            return repr(annotation).replace("typing.", "")
+        if isinstance(annotation, type):
+            if annotation.__module__ in ("builtins", base_module):
+                return annotation.__qualname__
+            return annotation.__module__ + "." + annotation.__qualname__
+        return repr(annotation)
 
     def inspect_formatargspec(
         args,
@@ -285,7 +296,7 @@ if py35:
         formatvarkw=lambda name: "**" + name,
         formatvalue=lambda value: "=" + repr(value),
         formatreturns=lambda text: " -> " + text,
-        formatannotation=formatannotation,
+        formatannotation=_formatannotation,
     ):
         """Copy formatargspec from python 3.7 standard library.