Re: [BUG] git-am silently applying patches incorrectly

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 4, 2011, 17:27 UTC
Message-ID: <7vvczy7q4c.fsf@alter.siamese.dyndns.org>
In-Reply-To: <4D711639.4070706@colin.guthr.ie>

Colin Guthrie <gmane@colin.guthr.ie> writes:

Show 6 quoted lines

>> If you just send the output of "git format-patch" untouched as an
>> attachment you can expect problems.
>
> Wow! I've never heard of this before... So you're saying it's actually
> invalid to do a git format-patch and then a git am on the files it
> generates?

I don't think you understand what Drew is saying.

The output from format-patch mimics mbox format already; it specifically was designed so that "format-patch --stdout | am" pipeline would work without your doing anything funky.

If you include the output from format-patch in your MUA, however, the message your MUA will send out would look like:

 * From: ... you ...
 * Subject: Hi, I am sending a patch (the message typed to your MUA)
 * Date: ... date ...

 % From <object name> <date looking format-patch signature string>
 % From: ... author name output by format patch
 % Subject: [PATCH] ... first paragraph from commit log message ...

 . The second paragraph and what follows...
 . ---
 . patch

In the above illustration, the lines marked with "*" are what your MUA would add as the header, and the ones marked with '%' are the headers format-patch placed to make its output look like mbox. You are supposed to move the "Subject: " line marked with '%' to the Subject input field of your MUA and drop all other lines marked with '%'.

Drew is talking about the problem it causes to the recipient if you did not do so, and left '%' lines in your MUA.