[PATCH] pull: ff --rebase --autostash works in dirty repo

[Tyler Brazier <tyler@tylerbrazier.com>]

pull --rebase --autostash was failing on a fast-forward in a dirty repo
since we shortcut to run_merge(), which does not know how to autostash.
The shortcut is a performance optimization, and since rebase was
rewritten in C, it seemed okay to just bypass the shortcut if we
autostash.
---
 builtin/pull.c  |  5 +++--
 t/t5520-pull.sh | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index dd1a4a94e41e..609e594d3f28 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -772,6 +772,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	struct oid_array merge_heads = OID_ARRAY_INIT;
 	struct object_id orig_head, curr_head;
 	struct object_id rebase_fork_point;
+	int autostash;
 
 	if (!getenv("GIT_REFLOG_ACTION"))
 		set_reflog_message(argc, argv);
@@ -800,8 +801,8 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (!opt_rebase && opt_autostash != -1)
 		die(_("--[no-]autostash option is only valid with --rebase."));
 
+	autostash = config_autostash;
 	if (opt_rebase) {
-		int autostash = config_autostash;
 		if (opt_autostash != -1)
 			autostash = opt_autostash;
 
@@ -868,7 +869,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 		head = lookup_commit_reference(orig_head.hash);
 		commit_list_insert(head, &list);
 		merge_head = lookup_commit_reference(merge_heads.oid[0].hash);
-		if (is_descendant_of(merge_head, list)) {
+		if (!autostash && is_descendant_of(merge_head, list)) {
 			/* we can fast-forward this without invoking rebase */
 			opt_ff = "--ff-only";
 			return run_merge();
diff --git a/t/t5520-pull.sh b/t/t5520-pull.sh
index 17f4d0fe4e72..4c85be0417cf 100755
--- a/t/t5520-pull.sh
+++ b/t/t5520-pull.sh
@@ -272,6 +272,24 @@ test_expect_success '--rebase fast forward' '
 	test_cmp reflog.expected reflog.fuzzy
 '
 
+test_expect_success '--rebase --autostash fast forward' '
+	test_when_finished "
+		git reset --hard;
+		git checkout to-rebase;
+		git branch -D to-rebase-ff;
+		git branch -D behind" &&
+	git branch behind &&
+	git checkout -b to-rebase-ff &&
+	echo another modification >>file &&
+	git add file &&
+	git commit -m mod &&
+
+	git checkout behind &&
+	echo dirty >file &&
+	git pull --rebase --autostash . to-rebase-ff &&
+	test "$(git rev-parse HEAD)" = "$(git rev-parse to-rebase-ff)"
+'
+
 test_expect_success '--rebase with conflicts shows advice' '
 	test_when_finished "git rebase --abort; git checkout -f to-rebase" &&
 	git checkout -b seq &&

--
https://github.com/git/git/pull/365