Merge branch 'jc/pull-rebase-ff' into maint

diff --git a/builtin/pull.c b/builtin/pull.c
index d6e46ee6d0054c152d721e92e354795c6f6002f8..3ecb881b0bcacbf1a453bf9a6cb95ae00cdecb1d 100644 (file)
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -857,10 +857,24 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
                if (merge_heads.nr > 1)
                        die(_("Cannot merge multiple branches into empty head."));
                return pull_into_void(*merge_heads.sha1, curr_head);
-       } else if (opt_rebase) {
-               if (merge_heads.nr > 1)
-                       die(_("Cannot rebase onto multiple branches."));
+       }
+       if (opt_rebase && merge_heads.nr > 1)
+               die(_("Cannot rebase onto multiple branches."));
+
+       if (opt_rebase) {
+               struct commit_list *list = NULL;
+               struct commit *merge_head, *head;
+
+               head = lookup_commit_reference(orig_head);
+               commit_list_insert(head, &list);
+               merge_head = lookup_commit_reference(merge_heads.sha1[0]);
+               if (is_descendant_of(merge_head, list)) {
+                       /* we can fast-forward this without invoking rebase */
+                       opt_ff = "--ff-only";
+                       return run_merge();
+               }
                return run_rebase(curr_head, *merge_heads.sha1, rebase_fork_point);
-       } else
+       } else {
                return run_merge();
+       }
 }