Re: [PATCH v3 3/3] cat-file: add "--literally" option

[Eric Sunshine <sunshine@sunshineco.com>]

On Thu, Mar 5, 2015 at 1:19 PM, Karthik Nayak <karthik.188@gmail.com> wrote:
> made changes to "cat-file" to include a "--literally"

Write in imperative mood: "Teach cat-file a --literally option..."

> option which prints the type of the object without any
> complaints.

Unfortunately, this explanation is quite lacking. What "complaints"?
What problem is --literally trying to solve? To answer these
questions, you will probably want to say something about the sort of
object which requires --literally, and how cat-file fails or behaves
without it.

> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
> diff --git a/builtin/cat-file.c b/builtin/cat-file.c
> index df99df4..60b9ec4 100644
> --- a/builtin/cat-file.c
> +++ b/builtin/cat-file.c
> @@ -323,7 +332,7 @@ static int batch_objects(struct batch_options *opt)
>  }
>
>  static const char * const cat_file_usage[] = {
> -       N_("git cat-file (-t | -s | -e | -p | <type> | --textconv) <object>"),
> +       N_("git cat-file (-t|-s|-e|-p|<type>|--textconv|-t --literally) <object>"),

This might read more naturally as:

    git cat-file (-t [--literally] | -s | -e | -p | <type> |
--textconv) <object>

rather than repeating the -t option.

>         N_("git cat-file (--batch | --batch-check) < <list-of-objects>"),
>         NULL
>  };
> @@ -369,6 +379,8 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
>                 OPT_SET_INT('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
>                 OPT_SET_INT(0, "textconv", &opt,
>                             N_("for blob objects, run textconv on object's content"), 'c'),
> +               OPT_BOOL( 0, "literally", &literally,
> +                         N_("show the type of the given loose object, use for debugging")),

Taking other help strings into account, there is no need for the
long-winded "type of the given loose object" when "loose object's
type" will suffice. More importantly, thought, you should try to say
something about how --literally is actually useful, such as for
"broken" objects or objects not of a known type.

>                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
>                         N_("show info and content of objects fed from the standard input"),
>                         PARSE_OPT_OPTARG, batch_option_callback },
> @@ -380,7 +392,7 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
>
>         git_config(git_cat_file_config, NULL);
>
> -       if (argc != 3 && argc != 2)
> +       if (argc != 3 && argc != 2 && argc != 4)

Perhaps it's time to rephrase this as "if (argc < 2 || argc > 4)"?

>                 usage_with_options(cat_file_usage, options);
>
>         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
> @@ -405,5 +417,10 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
>         if (batch.enabled)
>                 return batch_objects(&batch);
>
> -       return cat_one_file(opt, exp_type, obj_name);
> +       if (literally && opt == 't')
> +               return cat_one_file(opt, exp_type, obj_name, literally);
> +       else if (literally)
> +               usage_with_options(cat_file_usage, options);

I realize that existing cases in cat-file are already guilty of this
transgression, but it is quite annoying when a program merely spits
out its usage statement without actually telling you what you did
wrong; and it's often difficult to figure out why it was rejected. It
would be much more helpful in a case like this to state explicitly
that --literally was given without -t. (But perhaps such a
"friendliness" change is fodder for a separate patch.)

> +
> +       return cat_one_file(opt, exp_type, obj_name, literally);
>  }
> --
> 2.3.1.167.g7f4ba4b.dirty