Jens Troeger <jens.troe...@gmail.com> added the comment: David, I tried to find the mentioned '\r\r…\n' issue but I could not find it here. However, from an initial investigation into the BytesGenerator, here is what’s happening.
Flattening the body and attachments of the EmailMessage object works, and eventually _write_headers() is called to flatten the headers which happens entry by entry (https://github.com/python/cpython/blob/master/Lib/email/generator.py#L417-L418). Flattening a header entry is a recursive process over the parse tree of the entry, which builds the flattened and encoded final string by descending into the parse tree and encoding & concatenating the individual “parts” (tokens of the header entry). Given the parse tree for a header entry like "Martín Córdoba <f...@bar.com>" eventually results in the correct flattened string: '=?utf-8?q?Mart=C3=ADn_C=C3=B3rdoba?= <f...@bar.com>\r\n' at the bottom of the recursion for this “Mailbox” part. The recursive callstack is then: _refold_parse_tree _header_value_parser.py:2687 fold [Mailbox] _header_value_parser.py:144 _refold_parse_tree _header_value_parser.py:2630 fold [Address] _header_value_parser.py:144 _refold_parse_tree _header_value_parser.py:2630 fold [AddressList] _header_value_parser.py:144 _refold_parse_tree _header_value_parser.py:2630 fold [Header] _header_value_parser.py:144 fold [_UniqueAddressHeader] headerregistry.py:258 _fold [EmailPolicy] policy.py:205 fold_binary [EmailPolicy] policy.py:199 _write_headers [BytesGenerator] generator.py:418 _write [BytesGenerator] generator.py:195 The problem now arises from the interplay of # https://github.com/python/cpython/blob/master/Lib/email/_header_value_parser.py#L2629 encoded_part = part.fold(policy=policy)[:-1] # strip nl which strips the '\n' from the returned string, and # https://github.com/python/cpython/blob/master/Lib/email/_header_value_parser.py#L2686 return policy.linesep.join(lines) + policy.linesep which adds the policy’s line separation string linesep="\r\n" to the end of the flattened string upon unrolling the recursion. I am not sure about a proper fix here, but considering that the linesep policy can be any string length (in this case len("\r\n") == 2) a fixed truncation of one character [:-1] seems wrong. Instead, using: encoded_part = part.fold(policy=policy)[:-len(policy.linesep)] # strip nl seems to work for entries with and without Unicode characters in their display names. David, please advise on how to proceed from here. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue24218> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
