Merge part of the trunk changes into the p3yk branch. This merges from 43030

(branch-creation time) up to 43067. 43068 and 43069 contain a little
swapping action between re.py and sre.py, and this mightily confuses svn
merge, so later changes are going in separately.

This merge should break no additional tests.

The last-merged revision is going in a 'last_merge' property on '.' (the
branch directory.) Arbitrarily chosen, really; if there's a BCP for this, I
couldn't find it, but we can easily change it afterwards ;)

Lib/logging/__init__.py

@@ -1058,13 +1058,16 @@ class Logger(Filterer):
         file name, line number and function name.
         """
         f = currentframe().f_back
-        while 1:
+        rv = "(unknown file)", 0, "(unknown function)"
+        while hasattr(f, "f_code"):
             co = f.f_code
             filename = os.path.normcase(co.co_filename)
             if filename == _srcfile:
                 f = f.f_back
                 continue
-            return filename, f.f_lineno, co.co_name
+            rv = (filename, f.f_lineno, co.co_name)
+            break
+        return rv
 
     def makeRecord(self, name, level, fn, lno, msg, args, exc_info, func=None, extra=None):
         """