Re: [PATCH 2/5] run-command: allow stdin for run_processes_parallel

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 23, 2023, 22:52 UTC
Message-ID: <xmqq8rhslv8m.fsf@gitster.g>
In-Reply-To: <patch-2.5-81eef2f60a0-20230123T170551Z-avarab@gmail.com>

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

Show 16 quoted lines

> +	/*
> +	 * By default, do not inherit stdin from the parent process - otherwise,
> +	 * all children would share stdin! Users may overwrite this to provide
> +	 * something to the child's stdin by having their 'get_next_task'
> +	 * callback assign 0 to .no_stdin and an appropriate integer to .in.
> +	 */
> +	pp->children[i].process.no_stdin = 1;
> +
>  	code = opts->get_next_task(&pp->children[i].process,
>  				   opts->ungroup ? NULL : &pp->children[i].err,
>  				   opts->data,
> @@ -1601,7 +1609,6 @@ static int pp_start_one(struct parallel_processes *pp,
>  		pp->children[i].process.err = -1;
>  		pp->children[i].process.stdout_to_stderr = 1;
>  	}
> -	pp->children[i].process.no_stdin = 1;

For this single process, by default .no_stdin is set before it is passed to start_command(), so the default behaviour does not change.

This needs a new safety to ensure that processes that have .no_stdin turned off do not share the same value in their .in member, doesn't it? Hopefully that will be added in a later step in the series?

Provided that such a safety will appear in the end result, this conversion does make sense to me. Let's read on.

>  	if (start_command(&pp->children[i].process)) {
>  		if (opts->start_failure)