Re: [PATCH 03/10] run-command API: add and use a run_command_l_opt()

From: Junio C Hamano <gitster@pobox.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, "Jeff King" <peff@peff.net>,
	"René Scharfe" <l.s.r@web.de>
Subject: Re: [PATCH 03/10] run-command API: add and use a run_command_l_opt()
Date: Fri, 14 Oct 2022 11:40:27 -0700	[thread overview]
Message-ID: <xmqqtu468d0k.fsf@gitster.g> (raw)
In-Reply-To: <patch-03.10-fd81d44f221-20221014T153426Z-avarab@gmail.com> (=?utf-8?B?IsOGdmFyIEFybmZqw7Zyw7A=?= Bjarmason"'s message of "Fri, 14 Oct 2022 17:40:15 +0200")

Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:

>  bisect.c                 | 19 +++++++++----------
>  builtin/clone.c          | 16 ++++++----------
>  builtin/difftool.c       | 14 ++++++--------
>  builtin/gc.c             | 22 ++++++++--------------
>  builtin/merge.c          | 35 ++++++-----------------------------
>  builtin/remote.c         | 10 ++++------
>  compat/mingw.c           |  8 +++-----
>  ll-merge.c               |  4 +---
>  run-command.c            | 15 +++++++++++++++
>  run-command.h            | 13 +++++++++++--
>  sequencer.c              |  4 +---
>  t/helper/test-fake-ssh.c |  4 +---
>  12 files changed, 71 insertions(+), 93 deletions(-)

Nice.

> @@ -862,11 +858,11 @@ static void write_refspec_config(const char *src_ref_prefix,
>  
>  static void dissociate_from_references(void)
>  {
> -	static const char* argv[] = { "repack", "-a", "-d", NULL };

Good to see that this one in a wrong scope can now go away.

>  	char *alternates = git_pathdup("objects/info/alternates");
>  
>  	if (!access(alternates, F_OK)) {
> -		if (run_command_v_opt(argv, RUN_GIT_CMD|RUN_COMMAND_NO_STDIN))
> +		if (run_command_l_opt(RUN_GIT_CMD|RUN_COMMAND_NO_STDIN,
> +				      "repack",  "-a", "-d", NULL))
>  			die(_("cannot repack to clean up"));

> diff --git a/builtin/remote.c b/builtin/remote.c
> index 910f7b9316a..1d86c14297b 100644
> --- a/builtin/remote.c
> +++ b/builtin/remote.c
> @@ -92,13 +92,11 @@ static int verbose;
>  
>  static int fetch_remote(const char *name)
>  {
> -	const char *argv[] = { "fetch", name, NULL, NULL };
> -	if (verbose) {
> -		argv[1] = "-v";
> -		argv[2] = name;
> -	}
>  	printf_ln(_("Updating %s"), name);
> -	if (run_command_v_opt(argv, RUN_GIT_CMD))
> +	if (verbose && run_command_l_opt(RUN_GIT_CMD, "-v", "fetch", name,
> +					 NULL))
> +		return error(_("Could not fetch %s"), name);
> +	else if (run_command_l_opt(RUN_GIT_CMD, "fetch", name, NULL))
>  		return error(_("Could not fetch %s"), name);
>  	return 0;
>  }

This, together with the "merge" one that used to be conditional
(which I take as a sign that new callers can legitimately wish it to
be conditional again), is where the new l_opt() variant is weak.

And the above is wrong.  If verbose option is given and run command
succeeds in running "fetch -v" (another bug is that the updated code
is running "git -v fetch <name>"), we will try running "fetch" without
"-v" option after that.

So, for simplest things (i.e. the majority of places this patch
touches), addition of l_opt() is great.  Use of it for nontrivial
things like this is not.  We need to repeat ourselves, and the use
of API is error prone.

> diff --git a/compat/mingw.c b/compat/mingw.c
> index 901375d5841..4f5392c5796 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -196,17 +196,15 @@ static int read_yes_no_answer(void)
>  static int ask_yes_no_if_possible(const char *format, ...)
>  {
>  	char question[4096];
> -	const char *retry_hook[] = { NULL, NULL, NULL };

Good to see that this one in a wrong scope can now go away.

> +	char *retry_hook;
>  	va_list args;
>  
>  	va_start(args, format);
>  	vsnprintf(question, sizeof(question), format, args);
>  	va_end(args);
>  
> -	if ((retry_hook[0] = mingw_getenv("GIT_ASK_YESNO"))) {
> -		retry_hook[1] = question;
> -		return !run_command_v_opt(retry_hook, 0);
> -	}
> +	if ((retry_hook = mingw_getenv("GIT_ASK_YESNO")))
> +		return !run_command_l_opt(0, retry_hook, question, NULL);
>  
>  	if (!isatty(_fileno(stdin)) || !isatty(_fileno(stderr)))
>  		return 0;