Re: [PATCH v2 2/2] rebase: validate -C<n> and --whitespace=<mode> parameters early

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> It is a good idea to error out early upon seeing, say, `-Cbad`, rather
> than starting the rebase only to have the `--am` backend complain later.
>
> Let's do this.
>
> The only options accepting parameters which we pass through to `git am`
> (which may, or may not, forward them to `git apply`) are `-C` and
> `--whitespace`. The other options we pass through do not accept
> parameters, so we do not have to validate them here.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  builtin/rebase.c          | 12 +++++++++++-
>  t/t3406-rebase-message.sh |  7 +++++++
>  2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index 96ffa80b71..571cf899d5 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -1064,12 +1064,22 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
>  	}
>
>  	for (i = 0; i < options.git_am_opts.argc; i++) {
> -		const char *option = options.git_am_opts.argv[i];
> +		const char *option = options.git_am_opts.argv[i], *p;
>  		if (!strcmp(option, "--committer-date-is-author-date") ||
>  		    !strcmp(option, "--ignore-date") ||
>  		    !strcmp(option, "--whitespace=fix") ||
>  		    !strcmp(option, "--whitespace=strip"))
>  			options.flags |= REBASE_FORCE;
> +		else if (skip_prefix(option, "-C", &p)) {
> +			while (*p)
> +				if (!isdigit(*(p++)))
> +					die(_("switch `C' expects a "
> +					      "numerical value"));
> +		} else if (skip_prefix(option, "--whitespace=", &p)) {
> +			if (*p && strcmp(p, "warn") && strcmp(p, "nowarn") &&
> +			    strcmp(p, "error") && strcmp(p, "error-all"))
> +				die("Invalid whitespace option: '%s'", p);
> +		}
>  	}
>
>  	if (!(options.flags & REBASE_NO_QUIET))
> diff --git a/t/t3406-rebase-message.sh b/t/t3406-rebase-message.sh
> index 0392e36d23..2c79eed4fe 100755
> --- a/t/t3406-rebase-message.sh
> +++ b/t/t3406-rebase-message.sh
> @@ -84,4 +84,11 @@ test_expect_success 'rebase --onto outputs the invalid ref' '
>  	test_i18ngrep "invalid-ref" err
>  '
>
> +test_expect_success 'error out early upon -C<n> or --whitespace=<bad>' '
> +	test_must_fail git rebase -Cnot-a-number HEAD 2>err &&
> +	test_i18ngrep "numerical value" err &&
> +	test_must_fail git rebase --whitespace=bad HEAD 2>err &&
> +	test_i18ngrep "Invalid whitespace option" err
> +'
> +