Re: [PATCH v4 1/2] diff: move no-index detection to builtin/diff.c

> Hi,
>
> Thomas Gummerer wrote:
>
>> Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
>
> Thanks, and sorry for the slow follow-up.
>
> [...]
>> --- a/builtin/diff.c
>> +++ b/builtin/diff.c
>> @@ -16,6 +16,9 @@
> [...]
>> @@ -283,14 +286,57 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
>>  	 * Other cases are errors.
>>  	 */
>>
>> +	/* Were we asked to do --no-index explicitly? */
>> +	for (i = 1; i < argc; i++) {
>> +		if (!strcmp(argv[i], "--")) {
>> +			i++;
>> +			break;
>> +		}
>> +		if (!strcmp(argv[i], "--no-index"))
>> +			no_index = DIFF_NO_INDEX_EXPLICIT;
>
> Neat.
>
> [...]
>> +	/*
>> +	 * Treat git diff with at least one path outside of the
>> +	 * repo the same as if the command would have been executed
>> +	 * outside of a git repository.  In this case it behaves
>> +	 * the same way as "git diff --no-index <a> <b>", which acts
>> +	 * as a colourful "diff" replacement.
>> +	 */
>> +	if (nongit || ((argc == i + 2) &&
>> +		       (!path_inside_repo(prefix, argv[i]) ||
>> +			!path_inside_repo(prefix, argv[i + 1]))))
>> +		no_index = DIFF_NO_INDEX_IMPLICIT;
>
> What happens if I run 'git diff --no-index /tmp git.c git.c' from
> within a git repository?  With this, I fear I will get

> 	Not a git repository
> 	To compare two paths outside a working tree:
> 	usage: git diff [--no-index] <path> <path>
>
> instead of the expected
>
> 	usage: git diff --no-index <path> <path>
>
> Something like
>
> 	if (no_index)
> 		;
> 	else if (nongit)
> 		no_index = DIFF_NO_INDEX_IMPLICIT;
> 	else if (argc != i + 2)
> 		;
> 	else if (!path_inside_repo(prefix, argv[i]) ||
> 		 !path_inside_repo(prefix, argv[i + 1]))
> 		no_index = DIFF_NO_INDEX_IMPLICIT;
>
> should work.  Or:
>
> 	if (!no_index) {
> 		/*
> 		 * Treat git diff with ...
> 		 */
> 		if (nongit || ...)
> 			no_index = DIFF_NO_INDEX_IMPLICIT;
> 	}
>
> Or the '!no_index &&' condition inserted some other way.
>
>> -	/* If this is a no-index diff, just run it and exit there. */
>> -	diff_no_index(&rev, argc, argv, nongit, prefix);
>> +	if (no_index) {
>> +		if (argc != i + 2) {
> [...]
>> +			/* Give the usage message for non-repository usage and exit. */
>> +			usagef("git diff %s <path> <path>",
>> +			       no_index == DIFF_NO_INDEX_EXPLICIT ?
>> +					"--no-index" : "[--no-index]");
>> +
>> +		}
>> +		/* If this is a no-index diff, just run it and exit there. */
>> +		diff_no_index(&rev, argc, argv, prefix);
>> +	}
>
> Perhaps, to avoid some nesting:
>
> 	/* A no-index diff takes exactly two path arguments. */
> 	if (no_index && argc != i + 2) {
> 		...
> 		usagef(...);
> 	}
>
> 	if (no_index)
> 		/* Just run the diff and exit. */
> 		diff_no_index(...);
>
> Jonathan