mail: catch LookupError in headdecode()
We already catch this exception in _encode() (called by headencode()).
It gets raised when running test-notify.t with Python 3.
--- a/mercurial/mail.py Thu Oct 24 16:56:36 2019 +0200
+++ b/mercurial/mail.py Thu Oct 24 14:31:24 2019 +0200
@@ -458,7 +458,7 @@
try:
uparts.append(part.decode(charset))
continue
- except UnicodeDecodeError:
+ except (UnicodeDecodeError, LookupError):
pass
# On Python 3, decode_header() may return either bytes or unicode
# depending on whether the header has =?<charset>? or not