Issue 8143: sync unquote in urlparse with urllib; add comment about doing so.
unquote is duplicated in the two files to avoid a circular reference.
(This is fixed in Python3.) Updates keep getting made to the public unquote
without fixing the urlparse one, however, so this fix syncs the two
and adds a comment to both to make sure changes are applied to both.
diff --git a/Lib/urllib.py b/Lib/urllib.py
index de10c7e..de67f67 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -1156,6 +1156,10 @@
if match: return match.group(1, 2)
return attr, None
+# urlparse contains a duplicate of this method to avoid a circular import. If
+# you update this method, also update the copy in urlparse. This code
+# duplication does not exist in Python3.
+
_hexdig = '0123456789ABCDEFabcdef'
_hextochr = dict((a + b, chr(int(a + b, 16)))
for a in _hexdig for b in _hexdig)