describe: Refresh the index when run with --dirty

When running git describe --dirty the index should be refreshed.  Previously
the cached index would cause describe to think that the index was dirty when,
in reality, it was just stale.

The issue was exposed by python setuptools which hardlinks files into another
directory when building a distribution.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/describe.c b/builtin/describe.c
index 66fc291c8a81de71dee7b597c9ab0dc9d70e8e29..9f63067f50a6f49d61d40474608535905bec905b 100644 (file)
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -462,8 +462,21 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
                die(_("No names found, cannot describe anything."));
 
        if (argc == 0) {
-               if (dirty && !cmd_diff_index(ARRAY_SIZE(diff_index_args) - 1, diff_index_args, prefix))
-                       dirty = NULL;
+               if (dirty) {
+                       static struct lock_file index_lock;
+                       int fd;
+
+                       read_cache_preload(NULL);
+                       refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED,
+                                     NULL, NULL, NULL);
+                       fd = hold_locked_index(&index_lock, 0);
+                       if (0 <= fd)
+                               update_index_if_able(&the_index, &index_lock);
+
+                       if (!cmd_diff_index(ARRAY_SIZE(diff_index_args) - 1,
+                                           diff_index_args, prefix))
+                               dirty = NULL;
+               }
                describe("HEAD", 1);
        } else if (dirty) {
                die(_("--dirty is incompatible with committishes"));