py3: fix headencode() with display=False We previously called str() on a email.header.Header object. On Python 2, this returns a bytestring and the __str__ method is actually an alias to .encode() method. On Python 3, __str__ does not perform encoding (and returns a unicode string). To keep a consistent behavior across Python versions, we explicitly use .encode() and we wrap the result with encoding.strtolocal() to get a bytestring in all cases. As a side effect of forcing bytes conversion, we need to decode back in _addressencode(). This is to make test-notify.t pass on Python 3. Also note that headers are now encoded in some patchbomb tests; this is because the charset is not always "us-ascii" ("iso-8859-1" otherwise) on Python 3.

--- a/mercurial/mail.py	Thu Oct 24 14:31:24 2019 +0200
+++ b/mercurial/mail.py	Thu Oct 24 17:16:43 2019 +0200
@@ -362,13 +362,13 @@
     if not display:
         # split into words?
         s, cs = _encode(ui, s, charsets)
-        return str(email.header.Header(s, cs))
+        return encoding.strtolocal(email.header.Header(s, cs).encode())
     return s
 
 
 def _addressencode(ui, name, addr, charsets=None):
     assert isinstance(addr, bytes)
-    name = headencode(ui, name, charsets)
+    name = encoding.strfromlocal(headencode(ui, name, charsets))
     try:
         acc, dom = addr.split(b'@')
         acc.decode('ascii')