Merge pull request #1025 from LordGaav/fix-mro-on-jython. Fixes #1024.

Use a different method to lookup base classes on Jython

2 files changed, 20 insertions, 1 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index ebd18360..d83eb9d8 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,8 @@
+v35.0.2
+-------
+
+* #1024: Add workaround for Jython #2581 in monkey module.
+
 v35.0.1
 -------
 
diff --git a/setuptools/monkey.py b/setuptools/monkey.py
index 68fad9dd..acd0a4f4 100644
--- a/setuptools/monkey.py
+++ b/setuptools/monkey.py
@@ -21,6 +21,20 @@ if you think you need this functionality.
 """
 
 
+def _get_mro(cls):
+    """
+    Returns the bases classes for cls sorted by the MRO.
+
+    Works around an issue on Jython where inspect.getmro will not return all
+    base classes if multiple classes share the same name. Instead, this
+    function will return a tuple containing the class itself, and the contents
+    of cls.__bases__. See https://github.com/pypa/setuptools/issues/1024.
+    """
+    if platform.python_implementation() == "Jython":
+        return (cls,) + cls.__bases__
+    return inspect.getmro(cls)
+
+
 def get_unpatched(item):
     lookup = (
         get_unpatched_class if isinstance(item, six.class_types) else
@@ -38,7 +52,7 @@ def get_unpatched_class(cls):
     """
     external_bases = (
         cls
-        for cls in inspect.getmro(cls)
+        for cls in _get_mro(cls)
         if not cls.__module__.startswith('setuptools')
     )
     base = next(external_bases)