Subject: [PATCH 06/13] t5538: add tests to confirm deltas in shallow pushes

From: "Derrick Stolee via GitGitGadget" <[email-masked]>
Date: Mon, 10 Mar 2025 01:50:48 +0000

From: Derrick Stolee <[email-masked]>

It can be notoriously difficult to detect if delta bases are being
computed properly during 'git push'. Construct an example where it will
make a kilobyte worth of difference when a delta base is not found. We
can then use the progress indicators to distinguish between bytes and
KiB depending on whether the delta base is found and used.

Signed-off-by: Derrick Stolee <[email-masked]>
---
 t/t5538-push-shallow.sh | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/t/t5538-push-shallow.sh b/t/t5538-push-shallow.sh
index e91fcc173e8..11b85cca9e8 100755
--- a/t/t5538-push-shallow.sh
+++ b/t/t5538-push-shallow.sh
@@ -123,4 +123,38 @@ EOF
 	git cat-file blob $(echo 1|git hash-object --stdin) >/dev/null
 	)
 '
+
+test_expect_success 'push new commit from shallow clone has correct object count' '
+	git init origin &&
+	test_commit -C origin a &&
+	test_commit -C origin b &&
+
+	git clone --depth=1 "file://$(pwd)/origin" client &&
+	git -C client checkout -b topic &&
+	git -C client commit --allow-empty -m "empty" &&
+	GIT_PROGRESS_DELAY=0 git -C client push --progress origin topic 2>err &&
+	test_grep "Enumerating objects: 1, done." err
+'
+
+test_expect_success 'push new commit from shallow clone has good deltas' '
+	git init base &&
+	test_seq 1 999 >base/a &&
+	test_commit -C base initial &&
+	git -C base add a &&
+	git -C base commit -m "big a" &&
+
+	git clone --depth=1 "file://$(pwd)/base" deltas &&
+	git -C deltas checkout -b deltas &&
+	test_seq 1 1000 >deltas/a &&
+	git -C deltas commit -a -m "bigger a" &&
+	GIT_TRACE2_PERF="$(pwd)/trace.txt" \
+	GIT_PROGRESS_DELAY=0 git -C deltas push --progress origin deltas 2>err &&
+
+	test_grep "Enumerating objects: 5, done" err &&
+
+	# If the delta base is found, then this message uses "bytes".
+	# If the delta base is not found, then this message uses "KiB".
+	test_grep "Writing objects: .* bytes" err
+'
+
 test_done
-- 
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