Re: [PATCH] make config --add behave correctly for empty and NULL values

> Currently if we have a config file like,
> [foo]
>         baz
>         bar =
>
> and we try something like, "git config --add foo.baz roll", Git will
> segfault. Moreover, for "git config --add foo.bar roll", it will
> overwrite the original value instead of appending after the existing
> empty value.
>
> The problem lies with the regexp used for simulating --add in
> `git_config_set_multivar_in_file()`, "^$", which in ideal case should
> not match with any string but is true for empty strings. Instead use a
> regexp like "a^" which can not be true for any string, empty or not.
>
> For removing the segfault add a check for NULL values in `matches()` in
> config.c.