Merge branch 'ds/ahead-behind'

"git for-each-ref" learns '%(ahead-behind:<base>)' that computes the
distances from a single reference point in the history with bunch
of commits in bulk.

* ds/ahead-behind:
  commit-reach: add tips_reachable_from_bases()
  for-each-ref: add ahead-behind format atom
  commit-reach: implement ahead_behind() logic
  commit-graph: introduce `ensure_generations_valid()`
  commit-graph: return generation from memory
  commit-graph: simplify compute_generation_numbers()
  commit-graph: refactor compute_topological_levels()
  for-each-ref: explicitly test no matches
  for-each-ref: add --stdin option

1 files changed, 50 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..e14e7620cc
--- /dev/null
+++ b/t/perf/p1500-graph-walks.sh
@@ -0,0 +1,50 @@
+#!/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 'contains: git for-each-ref --merged' '
+	git for-each-ref --merged=HEAD --stdin <refs
+'
+
+test_perf 'contains: git branch --merged' '
+	xargs git branch --merged=HEAD <branches
+'
+
+test_perf 'contains: git tag --merged' '
+	xargs git tag --merged=HEAD <tags
+'
+
+test_done