Re: [RFC] send-email: support validate hook

>
> Changes there:
>
>  * use catdir instead of string concat, I don't know if we run
> format-patch on any platform where this matters in theory (e.g. VMS I
> think), but the file uses that API already, so continue using it.
>  * Just make this more brief by moving the -x test into the loop,
> we're sending E-Mail here, no need to optimize stat calls (you did ask
> for style advice :)
> * Check the return value of chdir & die appropriately
> * localize GIT_DIR
> * "die if system" is more idiomatic than "die unless system == 0"

> I wonder if we were designing this interface today whether whether the
> existing behavior of  --validate wouldn't just be shipped as a
> *.sample hook instead. There's also the caveat now that your hook
> might be OK with really long lines, but the existing validate function
> denies it, and there's no way to override that. I think a better way
> to do this is:
>
>         foreach my $f (@files) {
>                 unless (-p $f) {
> -                       my $error;
> -                       if ($use_hook) {
> -                               $hook[1] = abs_path($f);
> -                               my $cwd_save = cwd();
> -                               chdir($repo->wc_path() or $repo->repo_path());
> -                               $error = "rejected by sendemail-validate hook"
> -                                       unless system(@hook) == 0;
> -                               chdir($cwd_save);
> -                       }
> -                       $error = validate_patch($f) unless $error;
> +                       my $error = -x $validate_hook
> +                               ? validate_via_hook($validate_hook, $f)
> +                               : validate_patch($f);
>
> I.e. if you specify a validate hook it replaces the existing hardcoded behavior.