Re: git-apply does not work in a sub-directory of a Git repository

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 23, 2016, 16:55 UTC
Message-ID: <xmqqlh59cexj.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <xmqqbn65dxtl.fsf@gitster.mtv.corp.google.com>

Junio C Hamano <gitster@pobox.com> writes:

Show 8 quoted lines

> See
>
>   http://thread.gmane.org/gmane.comp.version-control.git/288316/focus=288321
>
> I agree it is bad that it silently ignores the path outside the
> directory.  When run with --verbose, we should say "Skipped X that
> is outside the directory." or something like that, just like we
> issue notices when we applied with offset, etc.

Another thing we may want to do is to loosen (or redo) the logic in builtin/apply.c::use_patch()

        static int use_patch(struct patch *p)
        {
                const char *pathname = p->new_name ? p->new_name : p->old_name;
                int i;

                /* Paths outside are not touched regardless of "--include" */
                if (0 < prefix_length) {
                        int pathlen = strlen(pathname);
                        if (pathlen <= prefix_length ||
                            memcmp(prefix, pathname, prefix_length))
                                return 0;
                }

The include/exclude mechanism does use wildmatch() but does not use the pathspec mechanism (it predates the pathspec machinery that was made reusable in places like this). We should be able to

    $ cd d/e/e/p/d/i/r
    $ git apply --include=:/ ../../../../../../../patch

to lift this limitation. IOW, we can think of the use_patch() to include only the paths in the subdirectory we are in by default, but we can make it allow --include/--exclude command line option to override that default.

That way, the plain-vanilla use would still retain the "when working in subdirectory, we only touch that subdirectory" behaviour, which existing scripts may depend on, but users can loosen the default as necessary.