git pull: Support --preserve-merges as a flag to rebase

Now that "git rebase" supports non-interactive rebases preserving merges, this patch is the next logical step for those who wish to use such a workflow.

Since this patch makes the last test marked as expecting failure in t3409-rebase-preserve-merges, we now alter it to expect success.

---

Documentation/git-pull.txt        |    4 ++++
git-pull.sh                       |    6 +++++-
t/t3409-rebase-preserve-merges.sh |    2 +-
3 files changed, 10 insertions(+), 2 deletions(-)

index 7578623..333fc55 100644
@@ -47,6 +47,10 @@ unless you have read linkgit:git-rebase[1] carefully.
--no-rebase::

	Override earlier --rebase.

+--preserve-merges::
+ Preserves merge commits when rebasing. Implies --rebase,
+ so the same warnings naturally apply.
+
include::fetch-options.txt[]

include::pull-fetch-param.txt[]

index 75c3610..270a50d 100755
@@ -58,6 +58,10 @@ do

	-r|--r|--re|--reb|--reba|--rebas|--rebase)
		rebase=true
		;;
+	--preserve-merges) # no short option for this
+		preserve_merges="--preserve-merges"
+		rebase=true
+		;;
	--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
		rebase=false
		;;

@@ -179,7 +183,7 @@ fi

merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit test true = "$rebase" &&
- exec git-rebase $strategy_args --onto $merge_head \

+	exec git-rebase $preserve_merges $strategy_args --onto $merge_head \
	${oldremoteref:-$merge_head}

exec git-merge $no_stat $no_commit $squash $no_ff $log_arg $strategy_args \
"$merge_name" HEAD $merge_head

index 21b8c79..9a376ef 100644
@@ -51,7 +51,7 @@ test_expect_success 'setup for merge-preserving rebase' \

git commit -a -m "Modify B2"
'

-test_expect_failure 'git pull --rebase -p on moved topic' ' +test_expect_success 'git pull --rebase -p on moved topic' '

	cd clone1 &&
	git pull --rebase --preserve-merges &&
	test $(git rev-list --all --pretty=oneline | grep "Modify A" | wc -l) = 1

1.6.0.2.307.gc4275.dirty

Does anyone know the current status of this?

The first 1/3 and 2/3 of this series is in next now (which grant non-interactive merge-preserving rebasing), but this additional --preserve-merges flag to git pull didn't seem to make it.

(Correct me if I'm wrong, I cannot pin point exactly where 1/2 and 2/3 got merged in, I'm just cheating and looking at the files as they exist in next's tip.)

My grandeur plan is to have this 3/3 go in as well and then follow it up with my patch to add a branch.name.preservemerges config variable.

This will make our internal workflow of "always rebase local changes/always preserve local merges" just work with "git pull".

Does this seem reasonable?

Thanks,
Stephen