Re: [PATCH] Documentation/git-blame.txt: --follow is a NO-OP

> On Tue, Sep 18, 2012 at 09:38:32PM -0700, Junio C Hamano wrote:
>
>> That is a totally wrong message to send.  You failed to teach the
>> reader that there is no need to do anything special to tell the
>> command to follow per-line origin across renames.
>> 
>> So if anything, I would phrase it this way instead:
>> 
>>     --follow::
>>           This option is accepted but silently ignored.  "git blame"
>> 	  follows per-line origin across renames without any special
>> 	  options, and there is no reason to use this option.
>
> I think that is much better than Drew's text. But I really wonder if the
> right solution is to simply disallow --follow. It does not do anything,
> and it is not documented. There is no special reason to think that it
> would do anything, except by people who try it. So perhaps that is the
> right time to say "no, this is not a valid option".
>
> Like this (totally untested) patch:
>
> diff --git a/builtin/blame.c b/builtin/blame.c
> index 0e102bf..412d6dd 100644
> --- a/builtin/blame.c
> +++ b/builtin/blame.c
> @@ -2365,6 +2365,10 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
>  			ctx.argv[0] = "--children";
>  			reverse = 1;
>  		}
> +		else if (!strcmp(ctx.argv[0], "--follow")) {
> +			error("unknown option `--follow`");
> +			usage_with_options(blame_opt_usage, options);
> +		}
>  		parse_revision_opt(&revs, &ctx, options, blame_opt_usage);
>  	}
>  parse_done: