[PATCH 1/2] t: add tests for ref tombstone scenarios
From: Kristofer Karlsson via GitGitGadget <hidden>
Date: 2026-07-06 13:36:01
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Kristofer Karlsson <redacted> Add a performance test and a correctness test for update-ref when many tombstones are present in a reftable. The performance test (p1401) exercises two scenarios: - All refs are deleted (creating tombstones) and then re-created with the same names, which currently exhibits quadratic behavior. - An asymmetric variant where refs are deleted and then new, differently-named refs are created. When the tombstones sort after the new refs, every create scans all tombstones, making this case even worse than re-creating the same refs. The correctness test (t0610) verifies that refs deleted and then re-created with the same names are visible afterwards. Helped-by: Jeff King [off-list ref] Signed-off-by: Kristofer Karlsson <redacted> --- t/perf/p1401-ref-store-tombstones.sh | 44 ++++++++++++++++++++++++++++ t/t0610-reftable-basics.sh | 22 ++++++++++++++ 2 files changed, 66 insertions(+) create mode 100755 t/perf/p1401-ref-store-tombstones.sh
diff --git a/t/perf/p1401-ref-store-tombstones.sh b/t/perf/p1401-ref-store-tombstones.sh
new file mode 100755
index 0000000000..e40a6dcbf4
--- /dev/null
+++ b/t/perf/p1401-ref-store-tombstones.sh@@ -0,0 +1,44 @@ +#!/bin/sh + +test_description="Tests performance of ref operations with many tombstones" + +. ./perf-lib.sh + +test_expect_success "setup" ' + git init --ref-format=reftable repo && + blob=$(echo foo | git -C repo hash-object -w --stdin) && + for i in $(test_seq 8000) + do + printf "create refs/tags/tag-%d %s\n" "$i" "$blob" || + return 1 + done >repo/input && + git -C repo update-ref --stdin <repo/input && + git -C repo for-each-ref --format="delete %(refname)" | + git -C repo update-ref --stdin +' + +test_perf "recreate refs after mass delete" ' + git -C repo update-ref --stdin <repo/input && + git -C repo for-each-ref --format="delete %(refname)" | + git -C repo update-ref --stdin +' + +test_expect_success "setup asymmetric" ' + for i in $(test_seq 8000) + do + printf "create refs/tags/old-%d %s\n" "$i" "$blob" || + return 1 + done >repo/input-old && + sed "s/old-/new-/" <repo/input-old >repo/input-new && + git -C repo update-ref --stdin <repo/input-old && + git -C repo for-each-ref --format="delete %(refname)" | + git -C repo update-ref --stdin +' + +test_perf "create new refs after deleting differently-named refs" ' + git -C repo update-ref --stdin <repo/input-new && + git -C repo for-each-ref --format="delete %(refname)" | + git -C repo update-ref --stdin +' + +test_done
diff --git a/t/t0610-reftable-basics.sh b/t/t0610-reftable-basics.sh
index e19e036898..4b7cfe38e4 100755
--- a/t/t0610-reftable-basics.sh
+++ b/t/t0610-reftable-basics.sh@@ -1163,4 +1163,26 @@ test_expect_success 'writes do not persist peeled value for invalid tags' ' ) ' +test_expect_success 'delete and re-create refs with tombstones' ' + test_when_finished "rm -rf repo" && + git init repo && + test_commit -C repo A && + A=$(git -C repo rev-parse HEAD) && + cat >input <<-EOF && + create refs/tags/a $A + create refs/tags/b $A + create refs/tags/c $A + EOF + git -C repo update-ref --stdin <input && + + # delete all tags, leaving tombstones + git -C repo for-each-ref --format="delete %(refname)" refs/tags/ | + git -C repo update-ref --stdin && + + # re-create the same refs and verify they are visible + git -C repo update-ref --stdin <input && + git -C repo tag -l >actual && + test_line_count = 3 actual +' + test_done
--
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