[PATCH v5 04/10] t6099, t6600: add side-exhaustion regression tests
From: Kristofer Karlsson via GitGitGadget <hidden>
Date: 2026-07-01 16:37:22
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Kristofer Karlsson <redacted> Add t6099 to test the case where multiple merge-base candidates exist and one is an ancestor of another. This exercises the side-exhaustion optimization in paint_down_to_common together with the remove_redundant safety net in get_merge_bases_many_0. Add a mixed finite/INFINITY test to t6600 where one tip is outside the commit-graph (INFINITY generation) and the other is inside. This exercises the region transition: the walk starts in the INFINITY region where side-exhaustion is disabled, then crosses into the finite region where it can fire. Signed-off-by: Kristofer Karlsson <redacted> --- t/meson.build | 1 + t/t6099-merge-base-side-exhaustion.sh | 82 +++++++++++++++++++++++++++ 2 files changed, 83 insertions(+) create mode 100755 t/t6099-merge-base-side-exhaustion.sh
diff --git a/t/meson.build b/t/meson.build
index 3219264fe7..ee6ebdffb9 100644
--- a/t/meson.build
+++ b/t/meson.build@@ -786,6 +786,7 @@ integration_tests = [ 't6041-bisect-submodule.sh', 't6050-replace.sh', 't6060-merge-index.sh', + 't6099-merge-base-side-exhaustion.sh', 't6100-rev-list-in-order.sh', 't6101-rev-parse-parents.sh', 't6102-rev-list-unexpected-objects.sh',
diff --git a/t/t6099-merge-base-side-exhaustion.sh b/t/t6099-merge-base-side-exhaustion.sh
new file mode 100755
index 0000000000..4f1e0d50ef
--- /dev/null
+++ b/t/t6099-merge-base-side-exhaustion.sh@@ -0,0 +1,82 @@ +#!/bin/sh + +test_description='merge-base with ancestor among merge-base candidates + +Test that merge-base --all correctly handles cases where +multiple merge-base candidates exist and one is an ancestor +of another. The side-exhaustion optimization in +paint_down_to_common may exit before STALE propagation +removes the ancestor, but remove_redundant catches it. + +Graph shape (parents are below children): + + A ----------- X + |\ /| + | B---------/ | + | | | + e2 \ f2 + | | | + e1 d1 f1 + \ | / + \ | / + \| / + C + +A and X are the two tips. +B and C are both reachable from A and X. +B reaches C through d1. +Only B should appear in merge-base --all output. +' + +GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main +export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME + +TEST_PASSES_SANITIZE_LEAK=true +. ./test-lib.sh + +test_expect_success 'setup ancestor merge-base candidate' ' + test_commit C && + + git checkout -b d-chain HEAD && + test_commit d1 && + test_commit B && + + git checkout -b e-path C && + test_commit e1 && + test_commit e2 && + + git checkout -b f-path C && + test_commit f1 && + test_commit f2 && + + git checkout -b branch-A e-path && + test_merge A B && + + git checkout -b branch-X f-path && + test_merge X B && + + git commit-graph write --reachable +' + +test_expect_success 'merge-base --all excludes ancestor candidate' ' + git rev-parse B >expected && + git merge-base --all A X >actual && + test_cmp expected actual +' + +test_expect_success 'merge-base (single) finds shallowest' ' + git rev-parse B >expected && + git merge-base A X >actual && + test_cmp expected actual +' + +# Without commit-graph: generation numbers are INFINITY, +# side-exhaustion optimization does not fire. +test_expect_success 'merge-base --all without commit-graph' ' + rm -f .git/objects/info/commit-graph && + git rev-parse B >expected && + git merge-base --all A X >actual && + test_cmp expected actual +' + +test_done
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