Re: "git add -p ." raises an unexpected "warning: empty strings as pathspecs will be made invalid in upcoming releases. please use . instead if you meant to match all paths"

> Kevin Daudt <me@ikke.info> writes:
>
>> On Wed, Nov 30, 2016 at 12:31:49PM -0800, Peter Urda wrote:
>>> After upgrading to version 2.11.0 I am getting a warning about empty
>>> strings as pathspecs while using 'patch'
>>> 
>>> - Ran 'git add -p .' from the root of my git repository.
>>> 
>>> - I was able to normally stage my changes, but was presented with a
>>> "warning: empty strings as pathspecs will be made invalid in upcoming
>>> releases. please use . instead if you meant to match all paths"
>>> message.
>>> 
>>> - I expected no warning message since I included a "." with my original command.
>>> 
>>> I believe that I should not be seeing this warning message as I
>>> included the requested "." pathspec.
>
> Yes, this seems to be caused by pathspec.c::prefix_pathspec()
> overwriting the original pathspec "." into "".  The callchain
> looks like this:
>
>     builtin/add.c::interactive_add()
>      -> parse_pathspec()
>         passes argv[] that has "." to the caller,
>         receives pathspec whose pathspec->items[].original
> 	is supposed to point at the unmolested original,
>         but prefix_pathspec() munges "." into ""
>      -> run_add_interactive()
>         which runs "git add--interactive" with
> 	pathspec->items[].original as pathspecs
>
>
> Perhaps this would work it around, but there should be a better way
> to fix it (like, making sure that what we call "original" indeed
> stays "original").
>
>  builtin/add.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/builtin/add.c b/builtin/add.c
> index e8fb80b36e..137097192d 100644
> --- a/builtin/add.c
> +++ b/builtin/add.c
> @@ -167,9 +167,18 @@ int run_add_interactive(const char *revision, const char *patch_mode,
>  	if (revision)
>  		argv_array_push(&argv, revision);
>  	argv_array_push(&argv, "--");
> -	for (i = 0; i < pathspec->nr; i++)
> +	for (i = 0; i < pathspec->nr; i++) {
>  		/* pass original pathspec, to be re-parsed */
> +		if (!*pathspec->items[i].original) {
> +			/*
> +			 * work around a misfeature in parse_pathspecs()
> +			 * that munges "." into "".
> +			 */
> +			argv_array_push(&argv, ".");
> +			continue;
> +		}
>  		argv_array_push(&argv, pathspec->items[i].original);
> +	}
>  
>  	status = run_command_v_opt(argv.argv, RUN_GIT_CMD);
>  	argv_array_clear(&argv);
> @@ -180,7 +189,7 @@ int interactive_add(int argc, const char **argv, const char *prefix, int patch)
>  {
>  	struct pathspec pathspec;
>  
> -	parse_pathspec(&pathspec, 0,
> +	parse_pathspec(&pathspec, 0,
>  		       PATHSPEC_PREFER_FULL |
>  		       PATHSPEC_SYMLINK_LEADING_PATH |
>  		       PATHSPEC_PREFIX_ORIGIN,