Re: Minor bug: git config ignores empty sections

From: Jeff King <peff@peff.net>
Date: Aug 15, 2016, 12:09 UTC
Message-ID: <20160815120916.6iobqirqbg76exms@sigill.intra.peff.net>
In-Reply-To: <CALO-gutdz5VMgoRmbqEa9UiaTC+L2Sy2n-3AF+zfPr-X8+1U4A@mail.gmail.com>

On Sun, Aug 14, 2016 at 09:29:27PM -0400, Eli Barzilay wrote:

Show 17 quoted lines

> Looks like there's a problem with setting a config with an empty
> section, making it create a new section.  The result is:
> 
>     $ git --version
>     git version 2.9.2
>     $ git init
>     Initialized empty Git repository in /home/eli/t/.git/
>     $ t() { git config x.y x; git config --unset x.y; }
>     $ t;t;t
>     $ grep -c '\[x\]' .git/config
>     3
>     $ git config x.z x
>     $ t;t;t
>     $ git config x.z x     # adds another [x], but leaves it populated
>     $ t;t;t;t;t;t;t;t
>     $ grep -c '\[x\]' .git/config
>     4

Yep. This is a very old and well-known bug. IIRC, the problem is that config updates use the regular callback-parser, so they see only the config keys themselves. Empty section headers never trigger them. Fixing it would require rewriting the config-update code.

And implicit in your test is the other bug, which is that deleting the last key in a section leaves the empty header. I think it's related to the same issue.

Patches welcome, of course.

-Peff