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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:47:53 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:47:53 +0000
commitc8bae7493d2f2910b57f13ded012e86bdcfb0532 (patch)
tree24e09d9f84dec336720cf393e156089ca2835791 /t/t5324-split-commit-graph.sh
parentInitial commit. (diff)
downloadgit-c8bae7493d2f2910b57f13ded012e86bdcfb0532.tar.xz
git-c8bae7493d2f2910b57f13ded012e86bdcfb0532.zip
Adding upstream version 1:2.39.2.upstream/1%2.39.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 't/t5324-split-commit-graph.sh')
-rwxr-xr-xt/t5324-split-commit-graph.sh651
1 files changed, 651 insertions, 0 deletions
diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
new file mode 100755
index 0000000..669ddc6
--- /dev/null
+++ b/t/t5324-split-commit-graph.sh
@@ -0,0 +1,651 @@
+#!/bin/sh
+
+test_description='split commit graph'
+. ./test-lib.sh
+
+GIT_TEST_COMMIT_GRAPH=0
+GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=0
+
+test_expect_success 'setup repo' '
+ git init &&
+ git config core.commitGraph true &&
+ git config gc.writeCommitGraph false &&
+ infodir=".git/objects/info" &&
+ graphdir="$infodir/commit-graphs" &&
+ test_oid_cache <<-EOM
+ shallow sha1:2132
+ shallow sha256:2436
+
+ base sha1:1408
+ base sha256:1528
+
+ oid_version sha1:1
+ oid_version sha256:2
+ EOM
+'
+
+graph_read_expect() {
+ NUM_BASE=0
+ if test ! -z $2
+ then
+ NUM_BASE=$2
+ fi
+ OPTIONS=
+ if test -z "$3"
+ then
+ OPTIONS=" read_generation_data"
+ fi
+ cat >expect <<- EOF
+ header: 43475048 1 $(test_oid oid_version) 4 $NUM_BASE
+ num_commits: $1
+ chunks: oid_fanout oid_lookup commit_metadata generation_data
+ options:$OPTIONS
+ EOF
+ test-tool read-graph >output &&
+ test_cmp expect output
+}
+
+test_expect_success POSIXPERM 'tweak umask for modebit tests' '
+ umask 022
+'
+
+test_expect_success 'create commits and write commit-graph' '
+ for i in $(test_seq 3)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git commit-graph write --reachable &&
+ test_path_is_file $infodir/commit-graph &&
+ graph_read_expect 3
+'
+
+graph_git_two_modes() {
+ git ${2:+ -C "$2"} -c core.commitGraph=true $1 >output &&
+ git ${2:+ -C "$2"} -c core.commitGraph=false $1 >expect &&
+ test_cmp expect output
+}
+
+graph_git_behavior() {
+ MSG=$1
+ BRANCH=$2
+ COMPARE=$3
+ DIR=$4
+ test_expect_success "check normal git operations: $MSG" '
+ graph_git_two_modes "log --oneline $BRANCH" "$DIR" &&
+ graph_git_two_modes "log --topo-order $BRANCH" "$DIR" &&
+ graph_git_two_modes "log --graph $COMPARE..$BRANCH" "$DIR" &&
+ graph_git_two_modes "branch -vv" "$DIR" &&
+ graph_git_two_modes "merge-base -a $BRANCH $COMPARE" "$DIR"
+ '
+}
+
+graph_git_behavior 'graph exists' commits/3 commits/1
+
+verify_chain_files_exist() {
+ for hash in $(cat $1/commit-graph-chain)
+ do
+ test_path_is_file $1/graph-$hash.graph || return 1
+ done
+}
+
+test_expect_success 'add more commits, and write a new base graph' '
+ git reset --hard commits/1 &&
+ for i in $(test_seq 4 5)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git reset --hard commits/2 &&
+ for i in $(test_seq 6 10)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git reset --hard commits/2 &&
+ git merge commits/4 &&
+ git branch merge/1 &&
+ git reset --hard commits/4 &&
+ git merge commits/6 &&
+ git branch merge/2 &&
+ git commit-graph write --reachable &&
+ graph_read_expect 12
+'
+
+test_expect_success 'fork and fail to base a chain on a commit-graph file' '
+ test_when_finished rm -rf fork &&
+ git clone . fork &&
+ (
+ cd fork &&
+ rm .git/objects/info/commit-graph &&
+ echo "$(pwd)/../.git/objects" >.git/objects/info/alternates &&
+ test_commit new-commit &&
+ git commit-graph write --reachable --split &&
+ test_path_is_file $graphdir/commit-graph-chain &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ verify_chain_files_exist $graphdir
+ )
+'
+
+test_expect_success 'add three more commits, write a tip graph' '
+ git reset --hard commits/3 &&
+ git merge merge/1 &&
+ git merge commits/5 &&
+ git merge merge/2 &&
+ git branch merge/3 &&
+ git commit-graph write --reachable --split &&
+ test_path_is_missing $infodir/commit-graph &&
+ test_path_is_file $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 2 graph-files &&
+ verify_chain_files_exist $graphdir
+'
+
+graph_git_behavior 'split commit-graph: merge 3 vs 2' merge/3 merge/2
+
+test_expect_success 'add one commit, write a tip graph' '
+ test_commit 11 &&
+ git branch commits/11 &&
+ git commit-graph write --reachable --split &&
+ test_path_is_missing $infodir/commit-graph &&
+ test_path_is_file $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 3 graph-files &&
+ verify_chain_files_exist $graphdir
+'
+
+graph_git_behavior 'three-layer commit-graph: commit 11 vs 6' commits/11 commits/6
+
+test_expect_success 'add one commit, write a merged graph' '
+ test_commit 12 &&
+ git branch commits/12 &&
+ git commit-graph write --reachable --split &&
+ test_path_is_file $graphdir/commit-graph-chain &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 2 graph-files &&
+ verify_chain_files_exist $graphdir
+'
+
+graph_git_behavior 'merged commit-graph: commit 12 vs 6' commits/12 commits/6
+
+test_expect_success 'create fork and chain across alternate' '
+ git clone . fork &&
+ (
+ cd fork &&
+ git config core.commitGraph true &&
+ rm -rf $graphdir &&
+ echo "$(pwd)/../.git/objects" >.git/objects/info/alternates &&
+ test_commit 13 &&
+ git branch commits/13 &&
+ git commit-graph write --reachable --split &&
+ test_path_is_file $graphdir/commit-graph-chain &&
+ test_line_count = 3 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files &&
+ git -c core.commitGraph=true rev-list HEAD >expect &&
+ git -c core.commitGraph=false rev-list HEAD >actual &&
+ test_cmp expect actual &&
+ test_commit 14 &&
+ git commit-graph write --reachable --split --object-dir=.git/objects/ &&
+ test_line_count = 3 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files
+ )
+'
+
+if test -d fork
+then
+ graph_git_behavior 'alternate: commit 13 vs 6' commits/13 origin/commits/6 "fork"
+fi
+
+test_expect_success 'test merge stragety constants' '
+ git clone . merge-2 &&
+ (
+ cd merge-2 &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 14 &&
+ git commit-graph write --reachable --split --size-multiple=2 &&
+ test_line_count = 3 $graphdir/commit-graph-chain
+
+ ) &&
+ git clone . merge-10 &&
+ (
+ cd merge-10 &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 14 &&
+ git commit-graph write --reachable --split --size-multiple=10 &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files
+ ) &&
+ git clone . merge-10-expire &&
+ (
+ cd merge-10-expire &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 15 &&
+ touch $graphdir/to-delete.graph $graphdir/to-keep.graph &&
+ test-tool chmtime =1546362000 $graphdir/to-delete.graph &&
+ test-tool chmtime =1546362001 $graphdir/to-keep.graph &&
+ git commit-graph write --reachable --split --size-multiple=10 \
+ --expire-time="2019-01-01 12:00 -05:00" &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ test_path_is_missing $graphdir/to-delete.graph &&
+ test_path_is_file $graphdir/to-keep.graph &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 3 graph-files
+ ) &&
+ git clone --no-hardlinks . max-commits &&
+ (
+ cd max-commits &&
+ git config core.commitGraph true &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test_commit 16 &&
+ test_commit 17 &&
+ git commit-graph write --reachable --split --max-commits=1 &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files
+ )
+'
+
+test_expect_success 'remove commit-graph-chain file after flattening' '
+ git clone . flatten &&
+ (
+ cd flatten &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ git commit-graph write --reachable &&
+ test_path_is_missing $graphdir/commit-graph-chain &&
+ ls $graphdir >graph-files &&
+ test_line_count = 0 graph-files
+ )
+'
+
+corrupt_file() {
+ file=$1
+ pos=$2
+ data="${3:-\0}"
+ chmod a+w "$file" &&
+ printf "$data" | dd of="$file" bs=1 seek="$pos" conv=notrunc
+}
+
+test_expect_success 'verify hashes along chain, even in shallow' '
+ git clone --no-hardlinks . verify &&
+ (
+ cd verify &&
+ git commit-graph verify &&
+ base_file=$graphdir/graph-$(head -n 1 $graphdir/commit-graph-chain).graph &&
+ corrupt_file "$base_file" $(test_oid shallow) "\01" &&
+ test_must_fail git commit-graph verify --shallow 2>test_err &&
+ grep -v "^+" test_err >err &&
+ test_i18ngrep "incorrect checksum" err
+ )
+'
+
+test_expect_success 'verify --shallow does not check base contents' '
+ git clone --no-hardlinks . verify-shallow &&
+ (
+ cd verify-shallow &&
+ git commit-graph verify &&
+ base_file=$graphdir/graph-$(head -n 1 $graphdir/commit-graph-chain).graph &&
+ corrupt_file "$base_file" 1000 "\01" &&
+ git commit-graph verify --shallow &&
+ test_must_fail git commit-graph verify 2>test_err &&
+ grep -v "^+" test_err >err &&
+ test_i18ngrep "incorrect checksum" err
+ )
+'
+
+test_expect_success 'warn on base graph chunk incorrect' '
+ git clone --no-hardlinks . base-chunk &&
+ (
+ cd base-chunk &&
+ git commit-graph verify &&
+ base_file=$graphdir/graph-$(tail -n 1 $graphdir/commit-graph-chain).graph &&
+ corrupt_file "$base_file" $(test_oid base) "\01" &&
+ git commit-graph verify --shallow 2>test_err &&
+ grep -v "^+" test_err >err &&
+ test_i18ngrep "commit-graph chain does not match" err
+ )
+'
+
+test_expect_success 'verify after commit-graph-chain corruption' '
+ git clone --no-hardlinks . verify-chain &&
+ (
+ cd verify-chain &&
+ corrupt_file "$graphdir/commit-graph-chain" 60 "G" &&
+ git commit-graph verify 2>test_err &&
+ grep -v "^+" test_err >err &&
+ test_i18ngrep "invalid commit-graph chain" err &&
+ corrupt_file "$graphdir/commit-graph-chain" 60 "A" &&
+ git commit-graph verify 2>test_err &&
+ grep -v "^+" test_err >err &&
+ test_i18ngrep "unable to find all commit-graph files" err
+ )
+'
+
+test_expect_success 'verify across alternates' '
+ git clone --no-hardlinks . verify-alt &&
+ (
+ cd verify-alt &&
+ rm -rf $graphdir &&
+ altdir="$(pwd)/../.git/objects" &&
+ echo "$altdir" >.git/objects/info/alternates &&
+ git commit-graph verify --object-dir="$altdir/" &&
+ test_commit extra &&
+ git commit-graph write --reachable --split &&
+ tip_file=$graphdir/graph-$(tail -n 1 $graphdir/commit-graph-chain).graph &&
+ corrupt_file "$tip_file" 100 "\01" &&
+ test_must_fail git commit-graph verify --shallow 2>test_err &&
+ grep -v "^+" test_err >err &&
+ test_i18ngrep "commit-graph has incorrect fanout value" err
+ )
+'
+
+test_expect_success 'add octopus merge' '
+ git reset --hard commits/10 &&
+ git merge commits/3 commits/4 &&
+ git branch merge/octopus &&
+ git commit-graph write --reachable --split &&
+ git commit-graph verify --progress 2>err &&
+ test_line_count = 3 err &&
+ test_i18ngrep ! warning err &&
+ test_line_count = 3 $graphdir/commit-graph-chain
+'
+
+graph_git_behavior 'graph exists' merge/octopus commits/12
+
+test_expect_success 'split across alternate where alternate is not split' '
+ git commit-graph write --reachable &&
+ test_path_is_file .git/objects/info/commit-graph &&
+ cp .git/objects/info/commit-graph . &&
+ git clone --no-hardlinks . alt-split &&
+ (
+ cd alt-split &&
+ rm -f .git/objects/info/commit-graph &&
+ echo "$(pwd)"/../.git/objects >.git/objects/info/alternates &&
+ test_commit 18 &&
+ git commit-graph write --reachable --split &&
+ test_line_count = 1 $graphdir/commit-graph-chain
+ ) &&
+ test_cmp commit-graph .git/objects/info/commit-graph
+'
+
+test_expect_success '--split=no-merge always writes an incremental' '
+ test_when_finished rm -rf a b &&
+ rm -rf $graphdir $infodir/commit-graph &&
+ git reset --hard commits/2 &&
+ git rev-list HEAD~1 >a &&
+ git rev-list HEAD >b &&
+ git commit-graph write --split --stdin-commits <a &&
+ git commit-graph write --split=no-merge --stdin-commits <b &&
+ test_line_count = 2 $graphdir/commit-graph-chain
+'
+
+test_expect_success '--split=replace replaces the chain' '
+ rm -rf $graphdir $infodir/commit-graph &&
+ git reset --hard commits/3 &&
+ git rev-list -1 HEAD~2 >a &&
+ git rev-list -1 HEAD~1 >b &&
+ git rev-list -1 HEAD >c &&
+ git commit-graph write --split=no-merge --stdin-commits <a &&
+ git commit-graph write --split=no-merge --stdin-commits <b &&
+ git commit-graph write --split=no-merge --stdin-commits <c &&
+ test_line_count = 3 $graphdir/commit-graph-chain &&
+ git commit-graph write --stdin-commits --split=replace <b &&
+ test_path_is_missing $infodir/commit-graph &&
+ test_path_is_file $graphdir/commit-graph-chain &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files &&
+ verify_chain_files_exist $graphdir &&
+ graph_read_expect 2
+'
+
+test_expect_success ULIMIT_FILE_DESCRIPTORS 'handles file descriptor exhaustion' '
+ git init ulimit &&
+ (
+ cd ulimit &&
+ for i in $(test_seq 64)
+ do
+ test_commit $i &&
+ run_with_limited_open_files test_might_fail git commit-graph write \
+ --split=no-merge --reachable || return 1
+ done
+ )
+'
+
+while read mode modebits
+do
+ test_expect_success POSIXPERM "split commit-graph respects core.sharedrepository $mode" '
+ rm -rf $graphdir $infodir/commit-graph &&
+ git reset --hard commits/1 &&
+ test_config core.sharedrepository "$mode" &&
+ git commit-graph write --split --reachable &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files &&
+ echo "$modebits" >expect &&
+ test_modebits $graphdir/graph-*.graph >actual &&
+ test_cmp expect actual &&
+ test_modebits $graphdir/commit-graph-chain >actual &&
+ test_cmp expect actual
+ '
+done <<\EOF
+0666 -r--r--r--
+0600 -r--------
+EOF
+
+test_expect_success '--split=replace with partial Bloom data' '
+ rm -rf $graphdir $infodir/commit-graph &&
+ git reset --hard commits/3 &&
+ git rev-list -1 HEAD~2 >a &&
+ git rev-list -1 HEAD~1 >b &&
+ git commit-graph write --split=no-merge --stdin-commits --changed-paths <a &&
+ git commit-graph write --split=no-merge --stdin-commits <b &&
+ git commit-graph write --split=replace --stdin-commits --changed-paths <c &&
+ ls $graphdir/graph-*.graph >graph-files &&
+ test_line_count = 1 graph-files &&
+ verify_chain_files_exist $graphdir
+'
+
+test_expect_success 'prevent regression for duplicate commits across layers' '
+ git init dup &&
+ git -C dup commit --allow-empty -m one &&
+ git -C dup -c core.commitGraph=false commit-graph write --split=no-merge --reachable 2>err &&
+ test_i18ngrep "attempting to write a commit-graph" err &&
+ git -C dup commit-graph write --split=no-merge --reachable &&
+ git -C dup commit --allow-empty -m two &&
+ git -C dup commit-graph write --split=no-merge --reachable &&
+ git -C dup commit --allow-empty -m three &&
+ git -C dup commit-graph write --split --reachable &&
+ git -C dup commit-graph verify
+'
+
+NUM_FIRST_LAYER_COMMITS=64
+NUM_SECOND_LAYER_COMMITS=16
+NUM_THIRD_LAYER_COMMITS=7
+NUM_FOURTH_LAYER_COMMITS=8
+NUM_FIFTH_LAYER_COMMITS=16
+SECOND_LAYER_SEQUENCE_START=$(($NUM_FIRST_LAYER_COMMITS + 1))
+SECOND_LAYER_SEQUENCE_END=$(($SECOND_LAYER_SEQUENCE_START + $NUM_SECOND_LAYER_COMMITS - 1))
+THIRD_LAYER_SEQUENCE_START=$(($SECOND_LAYER_SEQUENCE_END + 1))
+THIRD_LAYER_SEQUENCE_END=$(($THIRD_LAYER_SEQUENCE_START + $NUM_THIRD_LAYER_COMMITS - 1))
+FOURTH_LAYER_SEQUENCE_START=$(($THIRD_LAYER_SEQUENCE_END + 1))
+FOURTH_LAYER_SEQUENCE_END=$(($FOURTH_LAYER_SEQUENCE_START + $NUM_FOURTH_LAYER_COMMITS - 1))
+FIFTH_LAYER_SEQUENCE_START=$(($FOURTH_LAYER_SEQUENCE_END + 1))
+FIFTH_LAYER_SEQUENCE_END=$(($FIFTH_LAYER_SEQUENCE_START + $NUM_FIFTH_LAYER_COMMITS - 1))
+
+# Current split graph chain:
+#
+# 16 commits (No GDAT)
+# ------------------------
+# 64 commits (GDAT)
+#
+test_expect_success 'setup repo for mixed generation commit-graph-chain' '
+ graphdir=".git/objects/info/commit-graphs" &&
+ test_oid_cache <<-EOF &&
+ oid_version sha1:1
+ oid_version sha256:2
+ EOF
+ git init mixed &&
+ (
+ cd mixed &&
+ git config core.commitGraph true &&
+ git config gc.writeCommitGraph false &&
+ for i in $(test_seq $NUM_FIRST_LAYER_COMMITS)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git -c commitGraph.generationVersion=2 commit-graph write --reachable --split &&
+ graph_read_expect $NUM_FIRST_LAYER_COMMITS &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ for i in $(test_seq $SECOND_LAYER_SEQUENCE_START $SECOND_LAYER_SEQUENCE_END)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git -c commitGraph.generationVersion=1 commit-graph write --reachable --split=no-merge &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test-tool read-graph >output &&
+ cat >expect <<-EOF &&
+ header: 43475048 1 $(test_oid oid_version) 4 1
+ num_commits: $NUM_SECOND_LAYER_COMMITS
+ chunks: oid_fanout oid_lookup commit_metadata
+ options:
+ EOF
+ test_cmp expect output &&
+ git commit-graph verify &&
+ cat $graphdir/commit-graph-chain
+ )
+'
+
+# The new layer will be added without generation data chunk as it was not
+# present on the layer underneath it.
+#
+# 7 commits (No GDAT)
+# ------------------------
+# 16 commits (No GDAT)
+# ------------------------
+# 64 commits (GDAT)
+#
+test_expect_success 'do not write generation data chunk if not present on existing tip' '
+ git clone mixed mixed-no-gdat &&
+ (
+ cd mixed-no-gdat &&
+ for i in $(test_seq $THIRD_LAYER_SEQUENCE_START $THIRD_LAYER_SEQUENCE_END)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git commit-graph write --reachable --split=no-merge &&
+ test_line_count = 3 $graphdir/commit-graph-chain &&
+ test-tool read-graph >output &&
+ cat >expect <<-EOF &&
+ header: 43475048 1 $(test_oid oid_version) 4 2
+ num_commits: $NUM_THIRD_LAYER_COMMITS
+ chunks: oid_fanout oid_lookup commit_metadata
+ options:
+ EOF
+ test_cmp expect output &&
+ git commit-graph verify
+ )
+'
+
+# Number of commits in each layer of the split-commit graph before merge:
+#
+# 8 commits (No GDAT)
+# ------------------------
+# 7 commits (No GDAT)
+# ------------------------
+# 16 commits (No GDAT)
+# ------------------------
+# 64 commits (GDAT)
+#
+# The top two layers are merged and do not have generation data chunk as layer below them does
+# not have generation data chunk.
+#
+# 15 commits (No GDAT)
+# ------------------------
+# 16 commits (No GDAT)
+# ------------------------
+# 64 commits (GDAT)
+#
+test_expect_success 'do not write generation data chunk if the topmost remaining layer does not have generation data chunk' '
+ git clone mixed-no-gdat mixed-merge-no-gdat &&
+ (
+ cd mixed-merge-no-gdat &&
+ for i in $(test_seq $FOURTH_LAYER_SEQUENCE_START $FOURTH_LAYER_SEQUENCE_END)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git commit-graph write --reachable --split --size-multiple 1 &&
+ test_line_count = 3 $graphdir/commit-graph-chain &&
+ test-tool read-graph >output &&
+ cat >expect <<-EOF &&
+ header: 43475048 1 $(test_oid oid_version) 4 2
+ num_commits: $(($NUM_THIRD_LAYER_COMMITS + $NUM_FOURTH_LAYER_COMMITS))
+ chunks: oid_fanout oid_lookup commit_metadata
+ options:
+ EOF
+ test_cmp expect output &&
+ git commit-graph verify
+ )
+'
+
+# Number of commits in each layer of the split-commit graph before merge:
+#
+# 16 commits (No GDAT)
+# ------------------------
+# 15 commits (No GDAT)
+# ------------------------
+# 16 commits (No GDAT)
+# ------------------------
+# 64 commits (GDAT)
+#
+# The top three layers are merged and has generation data chunk as the topmost remaining layer
+# has generation data chunk.
+#
+# 47 commits (GDAT)
+# ------------------------
+# 64 commits (GDAT)
+#
+test_expect_success 'write generation data chunk if topmost remaining layer has generation data chunk' '
+ git clone mixed-merge-no-gdat mixed-merge-gdat &&
+ (
+ cd mixed-merge-gdat &&
+ for i in $(test_seq $FIFTH_LAYER_SEQUENCE_START $FIFTH_LAYER_SEQUENCE_END)
+ do
+ test_commit $i &&
+ git branch commits/$i || return 1
+ done &&
+ git commit-graph write --reachable --split --size-multiple 1 &&
+ test_line_count = 2 $graphdir/commit-graph-chain &&
+ test-tool read-graph >output &&
+ cat >expect <<-EOF &&
+ header: 43475048 1 $(test_oid oid_version) 5 1
+ num_commits: $(($NUM_SECOND_LAYER_COMMITS + $NUM_THIRD_LAYER_COMMITS + $NUM_FOURTH_LAYER_COMMITS + $NUM_FIFTH_LAYER_COMMITS))
+ chunks: oid_fanout oid_lookup commit_metadata generation_data
+ options: read_generation_data
+ EOF
+ test_cmp expect output
+ )
+'
+
+test_expect_success 'write generation data chunk when commit-graph chain is replaced' '
+ git clone mixed mixed-replace &&
+ (
+ cd mixed-replace &&
+ git commit-graph write --reachable --split=replace &&
+ test_path_is_file $graphdir/commit-graph-chain &&
+ test_line_count = 1 $graphdir/commit-graph-chain &&
+ verify_chain_files_exist $graphdir &&
+ graph_read_expect $(($NUM_FIRST_LAYER_COMMITS + $NUM_SECOND_LAYER_COMMITS)) &&
+ git commit-graph verify
+ )
+'
+
+test_done