git branch: avoid unnecessary object lookups

They can be expensive in the cold-cache case, so don't bother looking up
the commits for all branches unless we really need them for some reason.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-branch.c b/builtin-branch.c
index 3784dda0907d69561dbfa3838ebdb8795bce068e..0e30756b1b22f8c2fec3748411d669325245c294 100644 (file)
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -191,7 +191,7 @@ struct ref_item {
 
 struct ref_list {
        struct rev_info revs;
-       int index, alloc, maxwidth;
+       int index, alloc, maxwidth, verbose;
        struct ref_item *list;
        struct commit_list *with_commit;
        int kinds;
@@ -244,17 +244,20 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
        if ((kind & ref_list->kinds) == 0)
                return 0;
 
-       commit = lookup_commit_reference_gently(sha1, 1);
-       if (!commit)
-               return error("branch '%s' does not point at a commit", refname);
+       commit = NULL;
+       if (ref_list->verbose || ref_list->with_commit || merge_filter != NO_FILTER) {
+               commit = lookup_commit_reference_gently(sha1, 1);
+               if (!commit)
+                       return error("branch '%s' does not point at a commit", refname);
 
-       /* Filter with with_commit if specified */
-       if (!is_descendant_of(commit, ref_list->with_commit))
-               return 0;
+               /* Filter with with_commit if specified */
+               if (!is_descendant_of(commit, ref_list->with_commit))
+                       return 0;
 
-       if (merge_filter != NO_FILTER)
-               add_pending_object(&ref_list->revs,
-                                  (struct object *)commit, refname);
+               if (merge_filter != NO_FILTER)
+                       add_pending_object(&ref_list->revs,
+                                          (struct object *)commit, refname);
+       }
 
        /* Resize buffer */
        if (ref_list->index >= ref_list->alloc) {
@@ -423,6 +426,7 @@ static void print_ref_list(int kinds, int detached, int verbose, int abbrev, str
 
        memset(&ref_list, 0, sizeof(ref_list));
        ref_list.kinds = kinds;
+       ref_list.verbose = verbose;
        ref_list.with_commit = with_commit;
        if (merge_filter != NO_FILTER)
                init_revisions(&ref_list.revs, NULL);