Re: git log --pretty=format joins lines in the subject of commit message

From: Jeff King <peff@peff.net>
Date: Sep 17, 2010, 14:55 UTC
Message-ID: <20100917145522.GB2860@sigill.intra.peff.net>
In-Reply-To: <4D8D88A4-FEBF-4FA9-A39F-410D76289E4B@jetbrains.com>

On Fri, Sep 17, 2010 at 03:56:53PM +0400, Kirill Likhodedov wrote:

> I think that if it is a feature, it should be reflected in the
> documentation for custom pretty formats.

I agree it should be documented. I'm not sure where, though. The subject-munging affects more than just pretty formats. For example, at least git format-patch also has --keep-subjects to turn off munging. I guess a note should be made in a all relevant places.

> Anyway, that doesn't seem consistent enough: Git knows that the
> subject is "first line\nsecond line\nthird line" (because it shows it
> correctly in full or raw formats). Why does it join the lines in the
> custom format's %s?

Because then the consumer of "git log --format=%s" knows that they will get exactly one line per commit.

The convention in git is to do "subject\n\nbody", with subject on a single line. However, we often see commits imported from other version control systems without this format. The subject-munging is an attempt to make them useful in git-aware tools (e.g., gitk or gitweb, which show the subject). Showing just the first line of a multi-line subject is often useless. People complained, and we got the behavior we have today.

-Peff