[RFC WIP PATCH v8 13/13] WIP: can_fast_forward() support for --preserve-merges and --rebase-merges

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

This seems to work, needs more tests etc...

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/rebase.c               | 6 ++++++
 t/t3432-rebase-fast-forward.sh | 7 +++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/builtin/rebase.c b/builtin/rebase.c
index 167d4fcf67..de1c5cacb8 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -892,6 +892,12 @@ static void populate_merge_bases(struct commit *head, struct commit *onto,
 
 static int should_fast_forward(struct rebase_options *opts)
 {
+	if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
+		if (opts->rebase_merges)
+			return 1;
+		if (opts->type == REBASE_PRESERVE_MERGES)
+			return 1;
+	}
 	return !is_interactive(opts);
 }
 
diff --git a/t/t3432-rebase-fast-forward.sh b/t/t3432-rebase-fast-forward.sh
index e8a9bf42b6..d3e1815057 100755
--- a/t/t3432-rebase-fast-forward.sh
+++ b/t/t3432-rebase-fast-forward.sh
@@ -44,12 +44,13 @@ test_rebase_same_head_ () {
 	test_expect_$status "git rebase$flag $* with $changes is $what with $cmp HEAD" "
 		oldhead=\$(git rev-parse HEAD) &&
 		test_when_finished 'git reset --hard \$oldhead' &&
-		git rebase$flag $* >stdout &&
+		git rebase$flag $* >stdout 2>stderr &&
 		if test $what = work
 		then
 			# Must check this case first, for 'is up to
 			# date, rebase forced[...]rewinding head' cases
-			test_i18ngrep 'rewinding head' stdout
+			test_i18ngrep 'rewinding head' stdout ||
+			test_i18ngrep 'is up to date, rebase forced' stdout
 		elif test $what = noop
 		then
 			test_i18ngrep 'is up to date' stdout &&
@@ -79,6 +80,8 @@ test_rebase_same_head success noop same success noop-force same --keep-base mast
 test_rebase_same_head success noop same success noop-force same --keep-base
 test_rebase_same_head success noop same success noop-force same --no-fork-point
 test_rebase_same_head success noop same success noop-force same --keep-base --no-fork-point
+test_rebase_same_head success noop same success noop-force same --preserve-merges
+test_rebase_same_head success noop same success noop-force same --rebase-merges
 test_rebase_same_head success noop same success work same --fork-point master
 test_rebase_same_head success noop same success work diff --fork-point --onto B B
 test_rebase_same_head success noop same success work diff --fork-point --onto B... B
-- 
2.21.0.1020.gf2820cf01a