Subject: [PATCH v3 6/6] t3650: add more regression tests for failure conditions

From: [email-masked]
Date: Mon, 5 Jan 2026 20:53:22 +0100

From: Kristoffer Haugsbakk <[email-masked]>

There isn’t much test coverage for basic failure conditions. Let’s add
a few more since these are simple to write and remove if they become
obsolete.

Helped-by: Phillip Wood <[email-masked]>
Signed-off-by: Kristoffer Haugsbakk <[email-masked]>
---

Notes (series):
    v2:
    
    Improve test `option --onto or --advance is mandatory`. Phillip pointed out
    that using a pipe loses the return value. Instead let’s test the whole
    output by just appending `git replay -h` to `expect`.
    
    Also “normalize” to just using echo/printf for the `expect` since these are
    just oneliner errors.
    
    Also add two more tests (at the end).

 t/t3650-replay-basics.sh | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/t/t3650-replay-basics.sh b/t/t3650-replay-basics.sh
index d4399aa1662..d10c01506f1 100755
--- a/t/t3650-replay-basics.sh
+++ b/t/t3650-replay-basics.sh
@@ -41,10 +41,17 @@ test_expect_success 'setup' '
 
 	git switch main &&
 	test_commit L &&
 	test_commit M &&
 
+	git switch --detach topic4 &&
+	test_commit N &&
+	test_commit O &&
+	git switch -c topic-with-merge topic4 &&
+	test_merge P O --no-ff &&
+	git switch main &&
+
 	git switch -c conflict B &&
 	test_commit C.conflict C.t conflict
 '
 
 test_expect_success 'setup bare' '
@@ -63,10 +70,43 @@ test_expect_success '--onto with invalid commit-ish' '
 	printf "a valid commit-ish for --onto\n" >>expect &&
 	test_must_fail git replay --onto=refs/not-valid topic1..topic2 2>actual &&
 	test_cmp expect actual
 '
 
+test_expect_success 'option --onto or --advance is mandatory' '
+	echo "error: option --onto or --advance is mandatory" >expect &&
+	test_might_fail git replay -h >>expect &&
+	test_must_fail git replay topic1..topic2 2>actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'no base or negative ref gives no-replaying down to root error' '
+	echo "fatal: replaying down from root commit is not supported yet!" >expect &&
+	test_must_fail git replay --onto=topic1 topic2 2>actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'options --advance and --contained cannot be used together' '
+	printf "fatal: options ${SQ}--advance${SQ} " >expect &&
+	printf "and ${SQ}--contained${SQ} cannot be used together\n" >>expect &&
+	test_must_fail git replay --advance=main --contained \
+		topic1..topic2 2>actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'cannot advance target ... ordering would be ill-defined' '
+	echo "fatal: cannot advance target with multiple sources because ordering would be ill-defined" >expect &&
+	test_must_fail git replay --advance=main main topic1 topic2 2>actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'replaying merge commits is not supported yet' '
+	echo "fatal: replaying merge commits is not supported yet!" >expect &&
+	test_must_fail git replay --advance=main main..topic-with-merge 2>actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'using replay to rebase two branches, one on top of other' '
 	git replay --onto main topic1..topic2 >result &&
 
 	test_line_count = 1 result &&
 
-- 
2.52.0.383.gb1c58d6b301