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

Tanay Abhra [off-list ref] writes:

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.

I would have prefered two separate patches (or even better, 3, the first
one being "demonstrate failure of ..." with test_expect_failure) for
each issues.

But the fixes are straightforward, and the test actually test what it
has to test, so I think we can keep the patch as-is.

Thanks,

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/