Re: [RFC PATCH 1/2] fetch: set-head with --set-head option

[Jeff King <peff@peff.net>]

On Tue, Sep 10, 2024 at 10:24:58PM +0200, Bence Ferdinandy wrote:

> When cloning a repository refs/remotes/origin/HEAD is set automatically.
> In contrast, when using init, remote add and fetch to set a remote, one
> needs to call remote set-head --auto to achieve the same result.

Yes, I think this is a good goal, but...

> diff --git a/builtin/fetch.c b/builtin/fetch.c
> index b2b5aee5bf..6392314c6a 100644
> --- a/builtin/fetch.c
> +++ b/builtin/fetch.c
> @@ -1961,8 +1961,19 @@ static int fetch_finished(int result, struct strbuf *out,
>  	return 0;
>  }
>  
> -static int fetch_multiple(struct string_list *list, int max_children,
> -			  const struct fetch_config *config)
> +static int run_set_head(const char *name)
> +{
> +	struct child_process cmd = CHILD_PROCESS_INIT;
> +	strvec_push(&cmd.args, "remote");
> +	strvec_push(&cmd.args, "set-head");
> +	strvec_push(&cmd.args, "--auto");
> +	strvec_push(&cmd.args, name);
> +	cmd.git_cmd = 1;
> +	return run_command(&cmd);
> +}

...this is just calling "git remote" to do the real work. Which means
that git-remote is going to make its own separate connection to the
server (so slow, but may also require the user to reauthenticate, etc).

I think the intent of your patch 2 is that we'd only invoke this when we
saw a change, which mitigates the impact, but it still seems somewhat
hacky to me. We already have all of the information we need to do the
update inside fetch itself.

-Peff