Re: git config set --file, key-value pair without '= value', gives Segmentation fault

[Junio C Hamano <gitster@pobox.com>]

> So I think that the behavior dates back to c90702a1f6 (config: plumb
> --fixed-value into config API, 2020-11-25). I think that the fix looks
> something like:
>
> --- 8< ---
> diff --git a/config.c b/config.c
> index 6421894614..05f369ec0d 100644
> --- a/config.c
> +++ b/config.c
> @@ -2914,7 +2914,7 @@ static int matches(const char *key, const char *value,
>  {
>  	if (strcmp(key, store->key))
>  		return 0; /* not ours */
> -	if (store->fixed_value)
> +	if (store->fixed_value && value)
>  		return !strcmp(store->fixed_value, value);
>  	if (!store->value_pattern)
>  		return 1; /* always matches */

Hmph. fixed_value is about the string given on the command line
being not a pattern.  And value that is NULL is the valueless "true"
in this case.

I would have actually expected the fix that follow your analysis (by
the way, I found it really well done) would say something more like

	if (strcmp(key, store->key))
		return 0; /* not ours */
+	if (!value)
+		value = "true";
	if (store->fixed_value)
		return !strcmp(store->fixed_value, value);

but I am not sure exactly how we want to handle synonymous Boolean
values here.  Regardless of how "true" value is spelled in the
configuration file, e.g.

        [section]               [section]
                key                     key = true

I wonder if "git config set --value=yes [--fixed-value] section.key
false" should replace either of them to false.

It would especially true if the command is invoked with --type=bool
but it seems that the --type option does not participate in the
matching with the current value.

> I'd like to hear from Stolee (CC'd), who is the author of c90702a1f6
> before submitting this as a standalone patch.