From: Junio C Hamano <gitster@pobox.com>
Date: Thu, 13 Feb 2025 23:45:30 GMT
Subject: Re: [PATCH RFC] mailmap: fix check-mailmap with full mailmap line
Message-ID: <xmqqwmdtmmsl.fsf@gitster.g>
In-Reply-To: <20250213-jk-fix-sendemail-mailinfo-v1-1-c0b06c215f21@gmail.com>

Jacob Keller <jacob.e.keller@intel.com> writes:

> I recently had reported to me a crash from a coworker using the recently
> added sendemail mailmap support:
>
>   3724814 Segmentation fault      (core dumped) git check-mailmap "bugs@company.xx"

Thanks for relaying the report.
    
I can easily reproduce your segfault with our own mailmap, by
picking at random an entry with both name and e-mail listed as
the mapping source, e.g.

    $ git check-mailmap ksaitoh560@gmail.com

> With a mailmap file containing:
>
> A <a@domain.com> B <b@domain.com>
>
> I get the following unexpected result:
>
> $ git check-mailmap b@domain.com
> <b@domain.com>
>
> Based on my interpretation of the mailmap documentation, I would have
> expected this to translate to "A <a@domain.com>".

After reading "git help mailmap" twice, my interpretation is
different (disclaimer: I haven't read the implementation of the
mailmap code lately, and the last time I read any part of it is
probably at least a few years ago if not before).

Unlike "please map anybody with this e-mail address to 'A <a>'"
entry, which is spelled "A <a> <b>", the "fully spelled" form limits
the damage to those that match both name and e-mail, in order to
avoid "D <b>" from getting modified, while rewriting "B <b>" to "A
<a>".  So I would not expect a request with no name to be mapped at
all.

And the command emits the e-mail intact when it does not find any
match, "b@domain.com" being answered by "<b@domain.com>" is quite
expected from my point of view.

Thanks.