Fix documentation upload by fixing content_type in _build_multipart on Python 3.x.

setuptools/command/upload_docs.py

@@ -138,7 +138,7 @@ class upload_docs(upload):
         part_groups = map(builder, data.items())
         parts = itertools.chain.from_iterable(part_groups)
         body_items = itertools.chain(parts, end_items)
-        content_type = 'multipart/form-data; boundary=%s' % boundary
+        content_type = 'multipart/form-data; boundary=%s' % boundary.decode('ascii')
         return b''.join(body_items), content_type
 
     def upload_file(self, filename):

setuptools/tests/test_upload_docs.py

@@ -64,6 +64,8 @@ class TestUploadDocsTest:
         )
         body, content_type = upload_docs._build_multipart(data)
         assert 'form-data' in content_type
+        assert "b'" not in content_type
+        assert 'b"' not in content_type
         assert isinstance(body, bytes)
         assert b'foo' in body
         assert b'content' in body