Subject: Re: [PATCH] clone: handle empty config values in -c

From: Brandon Williams <[email-masked]>
Date: Mon, 1 May 2017 17:08:56 -0700

On 05/01, Jonathan Nieder wrote:
> "git clone --config" uses the following incantation to add an item to
> a config file, instead of replacing an existing value:
> 
> 	git_config_set_multivar_gently(key, value, "^$", 0)
> 
> As long as no existing value matches the regex ^$, that works as
> intended and adds to the config.  When a value is empty, though, it
> replaces the existing value.
> 
> Noticed while trying to set credential.helper during a clone to use a
> specific helper without inheriting from ~/.gitconfig and
> /etc/gitconfig.  That is, I ran
> 
> 	git clone -c credential.helper= \
> 		-c credential.helper=myhelper \
> 		https://example.com/repo
> 
> intending to produce the configuration
> 
> 	[credential]
> 		helper =
> 		helper = myhelper
> 
> Without this patch, the 'helper =' line is not included and the
> credential helper from /etc/gitconfig gets used.
> 
> Signed-off-by: Jonathan Nieder <[email-masked]>
> ---
> Thoughts?

After reading this I'm still a little fuzzy on why the empty helper line
is needed to avoid using the credential helper from /etc/gitconfig.

> 
> Thanks,
> Jonathan
> 
>  builtin/clone.c         | 4 +++-
>  t/t5611-clone-config.sh | 8 ++++++++
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/builtin/clone.c b/builtin/clone.c
> index de85b85254..a6ae7d6180 100644
> --- a/builtin/clone.c
> +++ b/builtin/clone.c
> @@ -773,7 +773,9 @@ static int checkout(int submodule_progress)
>  
>  static int write_one_config(const char *key, const char *value, void *data)
>  {
> -	return git_config_set_multivar_gently(key, value ? value : "true", "^$", 0);
> +	return git_config_set_multivar_gently(key,
> +					      value ? value : "true",
> +					      CONFIG_REGEX_NONE, 0);
>  }
>  
>  static void write_config(struct string_list *config)
> diff --git a/t/t5611-clone-config.sh b/t/t5611-clone-config.sh
> index e4850b778c..39329eb7a8 100755
> --- a/t/t5611-clone-config.sh
> +++ b/t/t5611-clone-config.sh
> @@ -19,6 +19,14 @@ test_expect_success 'clone -c can set multi-keys' '
>  	test_cmp expect actual
>  '
>  
> +test_expect_success 'clone -c can set multi-keys, including some empty' '
> +	rm -rf child &&
> +	git clone -c credential.helper= -c credential.helper=hi . child &&
> +	printf "%s\n" "" hi >expect &&
> +	git --git-dir=child/.git config --get-all credential.helper >actual &&
> +	test_cmp expect actual
> +'
> +
>  test_expect_success 'clone -c without a value is boolean true' '
>  	rm -rf child &&
>  	git clone -c core.foo . child &&
> -- 
> 2.13.0.rc1.294.g07d810a77f
> 

-- 
Brandon Williams