5 files changed, 187 insertions, 0 deletions
diff --git a/t/perf/p1500-graph-walks.sh b/t/perf/p1500-graph-walks.sh
new file mode 100755
index 0000000000..439a448c2e
--- /dev/null
+++ b/t/perf/p1500-graph-walks.sh
@@ -0,0 +1,45 @@
+#!/bin/sh
+
+test_description='Commit walk performance tests'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+test_expect_success 'setup' '
+	git for-each-ref --format="%(refname)" "refs/heads/*" "refs/tags/*" >allrefs &&
+	sort -r allrefs | head -n 50 >refs &&
+	for ref in $(cat refs)
+	do
+		git branch -f ref-$ref $ref &&
+		echo ref-$ref ||
+		return 1
+	done >branches &&
+	for ref in $(cat refs)
+	do
+		git tag -f tag-$ref $ref &&
+		echo tag-$ref ||
+		return 1
+	done >tags &&
+	git commit-graph write --reachable
+'
+
+test_perf 'ahead-behind counts: git for-each-ref' '
+	git for-each-ref --format="%(ahead-behind:HEAD)" --stdin <refs
+'
+
+test_perf 'ahead-behind counts: git branch' '
+	xargs git branch -l --format="%(ahead-behind:HEAD)" <branches
+'
+
+test_perf 'ahead-behind counts: git tag' '
+	xargs git tag -l --format="%(ahead-behind:HEAD)" <tags
+'
+
+test_perf 'ahead-behind counts: git rev-list' '
+	for r in $(cat refs)
+	do
+		git rev-list --count "HEAD..$r" || return 1
+	done
+'
+
+test_done
diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index d34d77f893..1c0f7ea24e 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -337,6 +337,20 @@ test_expect_success 'git branch --format option' '
 	test_cmp expect actual
 '
 
+test_expect_success 'git branch --format with ahead-behind' '
+	cat >expect <<-\EOF &&
+	(HEAD detached from fromtag) 0 0
+	refs/heads/ambiguous 0 0
+	refs/heads/branch-one 1 0
+	refs/heads/branch-two 0 0
+	refs/heads/main 1 0
+	refs/heads/ref-to-branch 1 0
+	refs/heads/ref-to-remote 1 0
+	EOF
+	git branch --format="%(refname) %(ahead-behind:HEAD)" >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'git branch with --format=%(rest) must fail' '
 	test_must_fail git branch --format="%(rest)" >actual
 '
diff --git a/t/t6301-for-each-ref-errors.sh b/t/t6301-for-each-ref-errors.sh
index bfda1f46ad..2667dd13fe 100755
--- a/t/t6301-for-each-ref-errors.sh
+++ b/t/t6301-for-each-ref-errors.sh
@@ -54,4 +54,18 @@ test_expect_success 'Missing objects are reported correctly' '
 	test_must_be_empty brief-err
 '
 
+test_expect_success 'ahead-behind requires an argument' '
+	test_must_fail git for-each-ref \
+		--format="%(ahead-behind)" 2>err &&
+	echo "fatal: expected format: %(ahead-behind:<committish>)" >expect &&
+	test_cmp expect err
+'
+
+test_expect_success 'missing ahead-behind base' '
+	test_must_fail git for-each-ref \
+		--format="%(ahead-behind:refs/heads/missing)" 2>err &&
+	echo "fatal: failed to find '\''refs/heads/missing'\''" >expect &&
+	test_cmp expect err
+'
+
 test_done
diff --git a/t/t6600-test-reach.sh b/t/t6600-test-reach.sh
index 338a9c46a2..0cb50797ef 100755
--- a/t/t6600-test-reach.sh
+++ b/t/t6600-test-reach.sh
@@ -443,4 +443,90 @@ test_expect_success 'get_reachable_subset:none' '
 	test_all_modes get_reachable_subset
 '
 
+test_expect_success 'for-each-ref ahead-behind:linear' '
+	cat >input <<-\EOF &&
+	refs/heads/commit-1-1
+	refs/heads/commit-1-3
+	refs/heads/commit-1-5
+	refs/heads/commit-1-8
+	EOF
+	cat >expect <<-\EOF &&
+	refs/heads/commit-1-1 0 8
+	refs/heads/commit-1-3 0 6
+	refs/heads/commit-1-5 0 4
+	refs/heads/commit-1-8 0 1
+	EOF
+	run_all_modes git for-each-ref \
+		--format="%(refname) %(ahead-behind:commit-1-9)" --stdin
+'
+
+test_expect_success 'for-each-ref ahead-behind:all' '
+	cat >input <<-\EOF &&
+	refs/heads/commit-1-1
+	refs/heads/commit-2-4
+	refs/heads/commit-4-2
+	refs/heads/commit-4-4
+	EOF
+	cat >expect <<-\EOF &&
+	refs/heads/commit-1-1 0 24
+	refs/heads/commit-2-4 0 17
+	refs/heads/commit-4-2 0 17
+	refs/heads/commit-4-4 0 9
+	EOF
+	run_all_modes git for-each-ref \
+		--format="%(refname) %(ahead-behind:commit-5-5)" --stdin
+'
+
+test_expect_success 'for-each-ref ahead-behind:some' '
+	cat >input <<-\EOF &&
+	refs/heads/commit-1-1
+	refs/heads/commit-5-3
+	refs/heads/commit-4-8
+	refs/heads/commit-9-9
+	EOF
+	cat >expect <<-\EOF &&
+	refs/heads/commit-1-1 0 53
+	refs/heads/commit-4-8 8 30
+	refs/heads/commit-5-3 0 39
+	refs/heads/commit-9-9 27 0
+	EOF
+	run_all_modes git for-each-ref \
+		--format="%(refname) %(ahead-behind:commit-9-6)" --stdin
+'
+
+test_expect_success 'for-each-ref ahead-behind:some, multibase' '
+	cat >input <<-\EOF &&
+	refs/heads/commit-1-1
+	refs/heads/commit-5-3
+	refs/heads/commit-7-8
+	refs/heads/commit-4-8
+	refs/heads/commit-9-9
+	EOF
+	cat >expect <<-\EOF &&
+	refs/heads/commit-1-1 0 53 0 53
+	refs/heads/commit-4-8 8 30 0 22
+	refs/heads/commit-5-3 0 39 0 39
+	refs/heads/commit-7-8 14 12 8 6
+	refs/heads/commit-9-9 27 0 27 0
+	EOF
+	run_all_modes git for-each-ref \
+		--format="%(refname) %(ahead-behind:commit-9-6) %(ahead-behind:commit-6-9)" \
+		--stdin
+'
+
+test_expect_success 'for-each-ref ahead-behind:none' '
+	cat >input <<-\EOF &&
+	refs/heads/commit-7-5
+	refs/heads/commit-4-8
+	refs/heads/commit-9-9
+	EOF
+	cat >expect <<-\EOF &&
+	refs/heads/commit-4-8 16 16
+	refs/heads/commit-7-5 7 4
+	refs/heads/commit-9-9 49 0
+	EOF
+	run_all_modes git for-each-ref \
+		--format="%(refname) %(ahead-behind:commit-8-4)" --stdin
+'
+
 test_done
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 9aa1660651..04a4b44183 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -792,6 +792,34 @@ test_expect_success 'annotations for blobs are empty' '
 	test_cmp expect actual
 '
 
+# Run this before doing any signing, so the test has the same results
+# regardless of the GPG prereq.
+test_expect_success 'git tag --format with ahead-behind' '
+	test_when_finished git reset --hard tag-one-line &&
+	git commit --allow-empty -m "left" &&
+	git tag -a -m left tag-left &&
+	git reset --hard HEAD~1 &&
+	git commit --allow-empty -m "right" &&
+	git tag -a -m left tag-right &&
+
+	# Use " !" at the end to demonstrate whitespace
+	# around empty ahead-behind token for tag-blob.
+	cat >expect <<-EOF &&
+	refs/tags/tag-blob  !
+	refs/tags/tag-left 1 1 !
+	refs/tags/tag-lines 0 1 !
+	refs/tags/tag-one-line 0 1 !
+	refs/tags/tag-right 0 0 !
+	refs/tags/tag-zero-lines 0 1 !
+	EOF
+	git tag -l --format="%(refname) %(ahead-behind:HEAD) !" >actual 2>err &&
+	grep "refs/tags/tag" actual >actual.focus &&
+	test_cmp expect actual.focus &&
+
+	# Error reported for tags that point to non-commits.
+	grep "error: object [0-9a-f]* is a blob, not a commit" err
+'
+
 # trying to verify annotated non-signed tags:
 
 test_expect_success GPG \