When parsing an mbox, it is possible to get existing In-Reply-To and References headers blindly appended into the headers of message we generate. This is probably the wrong thing to do and we should prioritize what was given in the command-line, cover letter, and previously-sent messages.
One example I've noticed in the wild was: https://public-inbox.org/git/20161111124541.8216-17-vascomalme...@sapo.pt/raw --- I'm not completely sure this is what Vasco was doing in that message, so it's an RFC for now... git-send-email.perl | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/git-send-email.perl b/git-send-email.perl index 068d60b3e6..5ab3d8585c 100755 --- a/git-send-email.perl +++ b/git-send-email.perl @@ -1543,7 +1543,13 @@ foreach my $t (@files) { elsif (!/^Date:\s/i && /^[-A-Za-z]+:\s+\S/) { push @xh, $_; } - + elsif (/^(?:References|In-Reply-To):/i) { + if (defined $initial_reply_to || $thread) { + warn +"Ignoring $_ header in mbox body since it conflicts with\n +--in-reply-to and --thread switches\n" + } + } } else { # In the traditional # "send lots of email" format, -- EW
