[PATCH v3 1/3] stash: add tests to ensure reflog --rewrite --updatref behavior

["John Cai via GitGitGadget" <gitgitgadget@gmail.com>]

From: John Cai <johncai86@gmail.com>

There is missing test coverage to ensure that the resulting reflogs
after a git stash drop has had its old oid rewritten if applicable, and
if the refs/stash has been updated if applicable.

Add two tests that verify both of these happen.

Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: John Cai <johncai86@gmail.com>
---
 t/t3903-stash.sh | 65 ++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 54 insertions(+), 11 deletions(-)

diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
index b149e2af441..73785cf862f 100755
--- a/t/t3903-stash.sh
+++ b/t/t3903-stash.sh
@@ -41,20 +41,29 @@ diff_cmp () {
 	rm -f "$1.compare" "$2.compare"
 }
 
-test_expect_success 'stash some dirty working directory' '
-	echo 1 >file &&
-	git add file &&
-	echo unrelated >other-file &&
-	git add other-file &&
+setup_stash() {
+	repo_dir=$1
+	if test -z $repo_dir; then
+		repo_dir="."
+	fi
+
+	echo 1 >$repo_dir/file &&
+	git -C $repo_dir add file &&
+	echo unrelated >$repo_dir/other-file &&
+	git -C $repo_dir add other-file &&
 	test_tick &&
-	git commit -m initial &&
-	echo 2 >file &&
+	git -C $repo_dir commit -m initial &&
+	echo 2 >$repo_dir/file &&
 	git add file &&
-	echo 3 >file &&
+	echo 3 >$repo_dir/file &&
 	test_tick &&
-	git stash &&
-	git diff-files --quiet &&
-	git diff-index --cached --quiet HEAD
+	git -C $repo_dir stash &&
+	git -C $repo_dir diff-files --quiet &&
+	git -C $repo_dir diff-index --cached --quiet HEAD
+}
+
+test_expect_success 'stash some dirty working directory' '
+	setup_stash
 '
 
 cat >expect <<EOF
@@ -185,6 +194,40 @@ test_expect_success 'drop middle stash by index' '
 	test 1 = $(git show HEAD:file)
 '
 
+test_expect_success 'drop stash reflog updates refs/stash' '
+	git reset --hard &&
+	git rev-parse refs/stash >expect &&
+	echo 9 >file &&
+	git stash &&
+	git stash drop stash@{0} &&
+	git rev-parse refs/stash >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success REFFILES 'drop stash reflog updates refs/stash with rewrite' '
+	git init repo &&
+	setup_stash repo &&
+	echo 9 >repo/file &&
+
+	old_oid="$(git -C repo rev-parse stash@{0})" &&
+	git -C repo stash &&
+	new_oid="$(git -C repo rev-parse stash@{0})" &&
+
+	cat >expect <<-EOF &&
+	$(test_oid zero) $old_oid
+	$old_oid $new_oid
+	EOF
+	cut -d" " -f1-2 repo/.git/logs/refs/stash >actual &&
+	test_cmp expect actual &&
+
+	git -C repo stash drop stash@{1} &&
+	cut -d" " -f1-2 repo/.git/logs/refs/stash >actual &&
+	cat >expect <<-EOF &&
+	$(test_oid zero) $new_oid
+	EOF
+	test_cmp expect actual
+'
+
 test_expect_success 'stash pop' '
 	git reset --hard &&
 	git stash pop &&
-- 
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