pull: avoid running both merge and rebase

When opt_rebase is true, we still first check if we can fast-forward.
If the branch is fast-forwardable, then we can avoid the rebase and just
use merge to do the fast-forward logic.  However, when commit a6d7eb2c7a
("pull: optionally rebase submodules (remote submodule changes only)",
2017-06-23) added the ability to rebase submodules it accidentally
caused us to run BOTH a merge and a rebase.  Add a flag to avoid doing
both.

This was found when a user had both pull.rebase and rebase.autosquash
set to true.  In such a case, the running of both merge and rebase would
cause ORIG_HEAD to be updated twice (and match HEAD at the end instead
of the commit before the rebase started), against expectation.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/pull.c b/builtin/pull.c
index d25ff13a60f2d08efdc160c359364ab94a5b19ae..e79ce01ecd4178e1bc56dd084ab60c8587ea1603 100644 (file)
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -986,6 +986,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 
        if (opt_rebase) {
                int ret = 0;
+               int ran_ff = 0;
                if ((recurse_submodules == RECURSE_SUBMODULES_ON ||
                     recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) &&
                    submodule_touches_in_range(the_repository, &rebase_fork_point, &curr_head))
@@ -1002,10 +1003,12 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
                        if (is_descendant_of(merge_head, list)) {
                                /* we can fast-forward this without invoking rebase */
                                opt_ff = "--ff-only";
+                               ran_ff = 1;
                                ret = run_merge();
                        }
                }
-               ret = run_rebase(&curr_head, merge_heads.oid, &rebase_fork_point);
+               if (!ran_ff)
+                       ret = run_rebase(&curr_head, merge_heads.oid, &rebase_fork_point);
 
                if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
                             recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))