Document and test the resolution of issue 3445 (tolerate missing attributes in functools.update_wrapper, previously implemented as a side effect of the __annotations__ copying patch) and implement issue 9567 (add a __wrapped__ attribute when using update_wrapper)

1 files changed, 7 insertions, 2 deletions

diff --git a/Lib/functools.py b/Lib/functools.py
index c2c2282..bd1334b 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -38,9 +38,14 @@ def update_wrapper(wrapper,
        are updated with the corresponding attribute from the wrapped
        function (defaults to functools.WRAPPER_UPDATES)
     """
+    wrapper.__wrapped__ = wrapped
     for attr in assigned:
-        if hasattr(wrapped, attr):
-            setattr(wrapper, attr, getattr(wrapped, attr))
+        try:
+            value = getattr(wrapped, attr)
+        except AttributeError:
+            pass
+        else:
+            setattr(wrapper, attr, value)
     for attr in updated:
         getattr(wrapper, attr).update(getattr(wrapped, attr, {}))
     # Return the wrapper so this can be used as a decorator via partial()