[PATCH v8 13/16] rebase --rebase-merges: avoid "empty merges"
- From
Johannes Schindelin <johannes.schindelin@gmx.de>
- Date
- Apr 21, 2018, 10:47 UTC
- Message-ID
- <nycvar.QRO.7.76.6.1804211247230.4241@ZVAVAG-6OXH6DA.rhebcr.pbec.zvpebfbsg.pbz>
- In-Reply-To
- <cover.1524306546.git.johannes.schindelin@gmx.de>
The `git merge` command does not allow merging commits that are already reachable from HEAD: `git merge HEAD^`, for example, will report that we are already up to date and not change a thing.
In an interactive rebase, such a merge could occur previously, e.g. when competing (or slightly modified) versions of a patch series were applied upstream, and the user had to `git rebase --skip` all of the local commits, and the topic branch becomes "empty" as a consequence.
Let's teach the todo command `merge` to behave the same as `git merge`.
Seeing as it requires some low-level trickery to create such merges with Git's commands in the first place, we do not even have to bother to introduce an option to force `merge` to create such merge commits.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> --- sequencer.c | 7 +++++++ t/t3430-rebase-merges.sh | 8 ++++++++ 2 files changed, 15 insertions(+)
diff --git a/sequencer.c b/sequencer.c index f3b4fe4d75f..443a0a0ee87 100644 --- a/sequencer.c +++ b/sequencer.c @@ -2803,6 +2803,13 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len, write_message("no-ff", 5, git_path_merge_mode(), 0); bases = get_merge_bases(head_commit, merge_commit); + if (bases && !oidcmp(&merge_commit->object.oid, + &bases->item->object.oid)) { + ret = 0; + /* skip merging an ancestor of HEAD */ + goto leave_merge; + } + for (j = bases; j; j = j->next) commit_list_insert(j->item, &reversed); free_commit_list(bases); diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh index e9c5dc1cd95..1628c8dcc20 100755 --- a/t/t3430-rebase-merges.sh +++ b/t/t3430-rebase-merges.sh @@ -215,4 +215,12 @@ test_expect_success 'post-rewrite hook and fixups work for merges' ' test_cmp expect actual ' +test_expect_success 'refuse to merge ancestors of HEAD' ' + echo "merge HEAD^" >script-from-scratch && + test_config -C wt sequence.editor \""$PWD"/replace-editor.sh\" && + before="$(git rev-parse HEAD)" && + git rebase -i HEAD && + test_cmp_rev HEAD $before +' + test_done
-- 2.17.0.windows.1.15.gaa56ade3205