Re: [PATCH 1/1] commit: make the sign-off trailer configurable

[Derrick Stolee <stolee@gmail.com>]

On 1/5/2020 12:41 PM, Hans Jerry Illikainen wrote:
> The commit builtin did not previously have a configuration option to
> enable the 'Signed-off-by' trailer by default.
> 
> For some use-cases (namely, when the user doesn't always have the right
> to contribute patches to a project) it makes sense to make it a
> conscientious decision to add the signoff trailer.  However, others'
> might always have the right to ship patches -- in which case it makes
> sense to have an option to add the trailer by default for projects that
> require it.

My initial thought was that the sign-off was supposed to be a purposeful
decision, but then I also realized that I never do anything in the Git
codebase that I _can't_ put online under the GPL. (It may not make it
upstream, but it will always be put online somewhere.)

> This patch introduces a commit.signOff configuration option that
> determine whether the trailer should be added for commits.  It can be
> overridden with the --(no-)signoff command-line option.

With that in mind, I think this is a valuable feature.
 
> Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com>

Did you generate this with your config option? ;)

> +commit.signOff::
> +	A boolean to specify whether commits should enable the
> +	`-s/--signoff` option by default.  *Note:* Adding the
> +	Signed-off-by: line to a commit message should be a conscious
> +	act and means that you certify you have the rights to submit the
> +	work under the same open source license.  Please see the
> +	'SubmittingPatches' document for further discussion.
> +

I wonder about the language of "should be a conscious act" here. It's
as if you are trying to convince someone to not use this feature. Perhaps
switch it to "is a deliberate act" and add something such as "Enable this
value only in repos where you are the only user and always have these
rights."

The multi-user scenario may be worth clarifying explicitly here. If there
is any chance that another user will join the machine and use that same
repo, then they would have a different user.name and user.email in their
global config (probably) but this as a local setting would provide their
sign-off.

> diff --git a/builtin/commit.c b/builtin/commit.c
> index c70ad01cc9..497e29c58c 100644
> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -1474,6 +1474,10 @@ static int git_commit_config(const char *k, const char *v, void *cb)
>  		sign_commit = git_config_bool(k, v) ? "" : NULL;
>  		return 0;
>  	}
> +	if (!strcmp(k, "commit.signoff")) {
> +		signoff = git_config_bool(k, v);
> +		return 0;
> +	}

Since we are directly modifying the same global used by the --[no-]signoff
option, I verified that the config options are checked before the arguments
are parsed. Thus, --no-signoff will override commit.signOff=true...

> +test_expect_success 'commit.signOff=true' '
> +	test_config commit.signOff true &&
> +	echo 1 >>positive &&
> +	git add positive &&
> +	git commit -m "thank you" &&
> +	git cat-file commit HEAD >commit.msg &&
> +	sed -ne "s/Signed-off-by: //p" commit.msg >actual &&
> +	git var GIT_COMMITTER_IDENT >ident &&
> +	sed -e "s/>.*/>/" ident >expected &&
> +	test_cmp expected actual
> +'
> +
> +test_expect_success 'commit.signOff=true and --no-signoff' '
> +	test_config commit.signOff true &&
> +	echo 2 >>positive &&
> +	git add positive &&
> +	git commit --no-signoff -m "thank you" &&
> +	git cat-file commit HEAD >commit.msg &&
> +	sed -ne "s/Signed-off-by: //p" commit.msg >actual &&
> +	git var GIT_COMMITTER_IDENT >ident &&
> +	sed -e "s/>.*/>/" ident >expected &&
> +	! test_cmp expected actual
> +'

...which you test here, too. Excellent.

> +test_expect_success 'commit.signOff=false and --signoff' '
> +	test_config commit.signOff false &&
> +	echo 1 >>positive &&
> +	git add positive &&
> +	git commit --signoff -m "thank you" &&

Perhaps it is worth adding an explicit "-c commit.signOff=false" here?

> +	git cat-file commit HEAD >commit.msg &&
> +	sed -ne "s/Signed-off-by: //p" commit.msg >actual &&
> +	git var GIT_COMMITTER_IDENT >ident &&
> +	sed -e "s/>.*/>/" ident >expected &&
> +	test_cmp expected actual
> +'
> +

I wonder if the boilerplate for these tests could be simplified or
shared across the tests?

For example: could we not just use test_i18ngrep to see if commit.msg
contains (or does not contain) the string "Signed-off-by"?

I believe this patch delivers the stated feature well. Hopefully others
can add commentary on its usefulness or possible issues in using it.

Thanks,
-Stolee