mv: check if <destination> is a SKIP_WORKTREE_DIR

Originally, <destination> is assumed to be in the working tree. If it is
not found as a directory, then it is determined to be either a regular file
path, or error out if used under the second form (move into a directory)
of 'git-mv'. Such behavior is not ideal, mainly because Git does not
look into the index for <destination>, which could potentially be a
SKIP_WORKTREE_DIR, which we need to determine for the later "moving from
in-cone to out-of-cone" patch.

Change the logic so that Git first check if <destination> is a directory
with all its contents sparsified (a SKIP_WORKTREE_DIR).

If <destination> is such a sparse directory, then we should modify the
index the same way as we would if this were a non-sparse directory. We
must be careful to ensure that the <destination> is marked with
SKIP_WORKTREE_DIR.

Also add a `dst_w_slash` to reuse the result from `add_slash()`, which
was everywhere and can be simplified.

Helped-by: Derrick Stolee <derrickstolee@github.com>
Helped-by: Victoria Dye <vdye@github.com>
Signed-off-by: Shaoxuan Yuan <shaoxuan.yuan02@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/mv.c b/builtin/mv.c
index c17df2a12f6b32a1766325907fd4b542c2c71704..11aea7b4db564baa247248898a157ac8b6bb4ed8 100644 (file)
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -171,6 +171,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
                OPT_END(),
        };
        const char **source, **destination, **dest_path, **submodule_gitfile;
+       const char *dst_w_slash;
        enum update_mode *modes;
        struct stat st;
        struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
@@ -200,6 +201,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
        if (argc == 1 && is_directory(argv[0]) && !is_directory(argv[1]))
                flags = 0;
        dest_path = internal_prefix_pathspec(prefix, argv + argc, 1, flags);
+       dst_w_slash = add_slash(dest_path[0]);
        submodule_gitfile = xcalloc(argc, sizeof(char *));
 
        if (dest_path[0][0] == '\0')
@@ -207,12 +209,20 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
                destination = internal_prefix_pathspec(dest_path[0], argv, argc, DUP_BASENAME);
        else if (!lstat(dest_path[0], &st) &&
                        S_ISDIR(st.st_mode)) {
-               dest_path[0] = add_slash(dest_path[0]);
-               destination = internal_prefix_pathspec(dest_path[0], argv, argc, DUP_BASENAME);
+               destination = internal_prefix_pathspec(dst_w_slash, argv, argc, DUP_BASENAME);
        } else {
-               if (argc != 1)
+               if (!path_in_sparse_checkout(dst_w_slash, &the_index) &&
+                   empty_dir_has_sparse_contents(dst_w_slash)) {
+                       destination = internal_prefix_pathspec(dst_w_slash, argv, argc, DUP_BASENAME);
+               } else if (argc != 1) {
                        die(_("destination '%s' is not a directory"), dest_path[0]);
-               destination = dest_path;
+               } else {
+                       destination = dest_path;
+               }
+       }
+       if (dst_w_slash != dest_path[0]) {
+               free((char *)dst_w_slash);
+               dst_w_slash = NULL;
        }
 
        /* Checking */