for-each-ref: add ahead-behind format atom
The previous change implemented the ahead_behind() method, including an
algorithm to compute the ahead/behind values for a number of commit tips
relative to a number of commit bases. Now, integrate that algorithm as
part of 'git for-each-ref' hidden behind a new format atom,
ahead-behind. This naturally extends to 'git branch' and 'git tag'
builtins, as well.
This format allows specifying multiple bases, if so desired, and all
matching references are compared against all of those bases. For this
reason, failing to read a reference provided from these atoms results in
an error.
In order to translate the ahead_behind() method information to the
format output code in ref-filter.c, we must populate arrays of
ahead_behind_count structs. In struct ref_array, we store the full array
that will be passed to ahead_behind(). In struct ref_array_item, we
store an array of pointers that point to the relvant items within the
full array. In this way, we can pull all relevant ahead/behind values
directly when formatting output for a specific item. It also ensures the
lifetime of the ahead_behind_count structs matches the time that the
array is being used.
Add specific tests of the ahead/behind counts in t6600-test-reach.sh, as
it has an interesting repository shape. In particular, its merging
strategy and its use of different commit-graphs would demonstrate over-
counting if the ahead_behind() method did not already account for that
possibility.
Also add tests for the specific for-each-ref, branch, and tag builtins.
In the case of 'git tag', there are intersting cases that happen when
some of the selected tips are not commits. This requires careful logic
around commits_nr in the second loop of filter_ahead_behind(). Also, the
test in t7004 is carefully located to avoid being dependent on the GPG
prereq. It also avoids using the test_commit helper, as that will add
ticks to the time and disrupt the expected timestamps in later tag
tests.
Also add performance tests in a new p1300-graph-walks.sh script. This
will be useful for more uses in the future, but for now compare the
ahead-behind counting algorithm in 'git for-each-ref' to the naive
implementation by running 'git rev-list --count' processes for each
input.
For the Git source code repository, the improvement is already obvious:
Test this tree
---------------------------------------------------------------
1500.2: ahead-behind counts: git for-each-ref 0.07(0.07+0.00)
1500.3: ahead-behind counts: git branch 0.07(0.06+0.00)
1500.4: ahead-behind counts: git tag 0.07(0.06+0.00)
1500.5: ahead-behind counts: git rev-list 1.32(1.04+0.27)
But the standard performance benchmark is the Linux kernel repository,
which demosntrates a significant improvement:
Test this tree
---------------------------------------------------------------
1500.2: ahead-behind counts: git for-each-ref 0.27(0.24+0.02)
1500.3: ahead-behind counts: git branch 0.27(0.24+0.03)
1500.4: ahead-behind counts: git tag 0.28(0.27+0.01)
1500.5: ahead-behind counts: git rev-list 4.57(4.03+0.54)
The 'git rev-list' test exists in this change as a demonstration, but it
will be removed in the next change to avoid wasting time on this
comparison.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/perf/p1500-graph-walks.sh b/t/perf/p1500-graph-walks.sh
new file mode 100755
index 0000000..439a448
--- /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 d34d77f..1c0f7ea 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -337,6 +337,20 @@
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 bfda1f4..2667dd1 100755
--- a/t/t6301-for-each-ref-errors.sh
+++ b/t/t6301-for-each-ref-errors.sh
@@ -54,4 +54,18 @@
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 338a9c4..0cb5079 100755
--- a/t/t6600-test-reach.sh
+++ b/t/t6600-test-reach.sh
@@ -443,4 +443,90 @@
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 9aa1660..04a4b44 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -792,6 +792,34 @@
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 \
