t/t5324-split-commit-graph.sh

   1 #!/bin/sh
   2
   3 test_description='split commit graph'
   4 . ./test-lib.sh
   5
   6 GIT_TEST_COMMIT_GRAPH=0
   7 GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=0
   8
   9 test_expect_success 'setup repo' '
  10         git init &&
  11         git config core.commitGraph true &&
  12         git config gc.writeCommitGraph false &&
  13         infodir=".git/objects/info" &&
  14         graphdir="$infodir/commit-graphs" &&
  15         test_oid_cache <<-EOM
  16         shallow sha1:2132
  17         shallow sha256:2436
  18
  19         base sha1:1408
  20         base sha256:1528
  21
  22         oid_version sha1:1
  23         oid_version sha256:2
  24         EOM
  25 '
  26
  27 graph_read_expect() {
  28         NUM_BASE=0
  29         if test ! -z $2
  30         then
  31                 NUM_BASE=$2
  32         fi
  33         cat >expect <<- EOF
  34         header: 43475048 1 $(test_oid oid_version) 4 $NUM_BASE
  35         num_commits: $1
  36         chunks: oid_fanout oid_lookup commit_metadata generation_data
  37         EOF
  38         test-tool read-graph >output &&
  39         test_cmp expect output
  40 }
  41
  42 test_expect_success POSIXPERM 'tweak umask for modebit tests' '
  43         umask 022
  44 '
  45
  46 test_expect_success 'create commits and write commit-graph' '
  47         for i in $(test_seq 3)
  48         do
  49                 test_commit $i &&
  50                 git branch commits/$i || return 1
  51         done &&
  52         git commit-graph write --reachable &&
  53         test_path_is_file $infodir/commit-graph &&
  54         graph_read_expect 3
  55 '
  56
  57 graph_git_two_modes() {
  58         git ${2:+ -C "$2"} -c core.commitGraph=true $1 >output &&
  59         git ${2:+ -C "$2"} -c core.commitGraph=false $1 >expect &&
  60         test_cmp expect output
  61 }
  62
  63 graph_git_behavior() {
  64         MSG=$1
  65         BRANCH=$2
  66         COMPARE=$3
  67         DIR=$4
  68         test_expect_success "check normal git operations: $MSG" '
  69                 graph_git_two_modes "log --oneline $BRANCH" "$DIR" &&
  70                 graph_git_two_modes "log --topo-order $BRANCH" "$DIR" &&
  71                 graph_git_two_modes "log --graph $COMPARE..$BRANCH" "$DIR" &&
  72                 graph_git_two_modes "branch -vv" "$DIR" &&
  73                 graph_git_two_modes "merge-base -a $BRANCH $COMPARE" "$DIR"
  74         '
  75 }
  76
  77 graph_git_behavior 'graph exists' commits/3 commits/1
  78
  79 verify_chain_files_exist() {
  80         for hash in $(cat $1/commit-graph-chain)
  81         do
  82                 test_path_is_file $1/graph-$hash.graph || return 1
  83         done
  84 }
  85
  86 test_expect_success 'add more commits, and write a new base graph' '
  87         git reset --hard commits/1 &&
  88         for i in $(test_seq 4 5)
  89         do
  90                 test_commit $i &&
  91                 git branch commits/$i || return 1
  92         done &&
  93         git reset --hard commits/2 &&
  94         for i in $(test_seq 6 10)
  95         do
  96                 test_commit $i &&
  97                 git branch commits/$i || return 1
  98         done &&
  99         git reset --hard commits/2 &&
 100         git merge commits/4 &&
 101         git branch merge/1 &&
 102         git reset --hard commits/4 &&
 103         git merge commits/6 &&
 104         git branch merge/2 &&
 105         git commit-graph write --reachable &&
 106         graph_read_expect 12
 107 '
 108
 109 test_expect_success 'fork and fail to base a chain on a commit-graph file' '
 110         test_when_finished rm -rf fork &&
 111         git clone . fork &&
 112         (
 113                 cd fork &&
 114                 rm .git/objects/info/commit-graph &&
 115                 echo "$(pwd)/../.git/objects" >.git/objects/info/alternates &&
 116                 test_commit new-commit &&
 117                 git commit-graph write --reachable --split &&
 118                 test_path_is_file $graphdir/commit-graph-chain &&
 119                 test_line_count = 1 $graphdir/commit-graph-chain &&
 120                 verify_chain_files_exist $graphdir
 121         )
 122 '
 123
 124 test_expect_success 'add three more commits, write a tip graph' '
 125         git reset --hard commits/3 &&
 126         git merge merge/1 &&
 127         git merge commits/5 &&
 128         git merge merge/2 &&
 129         git branch merge/3 &&
 130         git commit-graph write --reachable --split &&
 131         test_path_is_missing $infodir/commit-graph &&
 132         test_path_is_file $graphdir/commit-graph-chain &&
 133         ls $graphdir/graph-*.graph >graph-files &&
 134         test_line_count = 2 graph-files &&
 135         verify_chain_files_exist $graphdir
 136 '
 137
 138 graph_git_behavior 'split commit-graph: merge 3 vs 2' merge/3 merge/2
 139
 140 test_expect_success 'add one commit, write a tip graph' '
 141         test_commit 11 &&
 142         git branch commits/11 &&
 143         git commit-graph write --reachable --split &&
 144         test_path_is_missing $infodir/commit-graph &&
 145         test_path_is_file $graphdir/commit-graph-chain &&
 146         ls $graphdir/graph-*.graph >graph-files &&
 147         test_line_count = 3 graph-files &&
 148         verify_chain_files_exist $graphdir
 149 '
 150
 151 graph_git_behavior 'three-layer commit-graph: commit 11 vs 6' commits/11 commits/6
 152
 153 test_expect_success 'add one commit, write a merged graph' '
 154         test_commit 12 &&
 155         git branch commits/12 &&
 156         git commit-graph write --reachable --split &&
 157         test_path_is_file $graphdir/commit-graph-chain &&
 158         test_line_count = 2 $graphdir/commit-graph-chain &&
 159         ls $graphdir/graph-*.graph >graph-files &&
 160         test_line_count = 2 graph-files &&
 161         verify_chain_files_exist $graphdir
 162 '
 163
 164 graph_git_behavior 'merged commit-graph: commit 12 vs 6' commits/12 commits/6
 165
 166 test_expect_success 'create fork and chain across alternate' '
 167         git clone . fork &&
 168         (
 169                 cd fork &&
 170                 git config core.commitGraph true &&
 171                 rm -rf $graphdir &&
 172                 echo "$(pwd)/../.git/objects" >.git/objects/info/alternates &&
 173                 test_commit 13 &&
 174                 git branch commits/13 &&
 175                 git commit-graph write --reachable --split &&
 176                 test_path_is_file $graphdir/commit-graph-chain &&
 177                 test_line_count = 3 $graphdir/commit-graph-chain &&
 178                 ls $graphdir/graph-*.graph >graph-files &&
 179                 test_line_count = 1 graph-files &&
 180                 git -c core.commitGraph=true  rev-list HEAD >expect &&
 181                 git -c core.commitGraph=false rev-list HEAD >actual &&
 182                 test_cmp expect actual &&
 183                 test_commit 14 &&
 184                 git commit-graph write --reachable --split --object-dir=.git/objects/ &&
 185                 test_line_count = 3 $graphdir/commit-graph-chain &&
 186                 ls $graphdir/graph-*.graph >graph-files &&
 187                 test_line_count = 1 graph-files
 188         )
 189 '
 190
 191 if test -d fork
 192 then
 193         graph_git_behavior 'alternate: commit 13 vs 6' commits/13 origin/commits/6 "fork"
 194 fi
 195
 196 test_expect_success 'test merge stragety constants' '
 197         git clone . merge-2 &&
 198         (
 199                 cd merge-2 &&
 200                 git config core.commitGraph true &&
 201                 test_line_count = 2 $graphdir/commit-graph-chain &&
 202                 test_commit 14 &&
 203                 git commit-graph write --reachable --split --size-multiple=2 &&
 204                 test_line_count = 3 $graphdir/commit-graph-chain
 205
 206         ) &&
 207         git clone . merge-10 &&
 208         (
 209                 cd merge-10 &&
 210                 git config core.commitGraph true &&
 211                 test_line_count = 2 $graphdir/commit-graph-chain &&
 212                 test_commit 14 &&
 213                 git commit-graph write --reachable --split --size-multiple=10 &&
 214                 test_line_count = 1 $graphdir/commit-graph-chain &&
 215                 ls $graphdir/graph-*.graph >graph-files &&
 216                 test_line_count = 1 graph-files
 217         ) &&
 218         git clone . merge-10-expire &&
 219         (
 220                 cd merge-10-expire &&
 221                 git config core.commitGraph true &&
 222                 test_line_count = 2 $graphdir/commit-graph-chain &&
 223                 test_commit 15 &&
 224                 touch $graphdir/to-delete.graph $graphdir/to-keep.graph &&
 225                 test-tool chmtime =1546362000 $graphdir/to-delete.graph &&
 226                 test-tool chmtime =1546362001 $graphdir/to-keep.graph &&
 227                 git commit-graph write --reachable --split --size-multiple=10 \
 228                         --expire-time="2019-01-01 12:00 -05:00" &&
 229                 test_line_count = 1 $graphdir/commit-graph-chain &&
 230                 test_path_is_missing $graphdir/to-delete.graph &&
 231                 test_path_is_file $graphdir/to-keep.graph &&
 232                 ls $graphdir/graph-*.graph >graph-files &&
 233                 test_line_count = 3 graph-files
 234         ) &&
 235         git clone --no-hardlinks . max-commits &&
 236         (
 237                 cd max-commits &&
 238                 git config core.commitGraph true &&
 239                 test_line_count = 2 $graphdir/commit-graph-chain &&
 240                 test_commit 16 &&
 241                 test_commit 17 &&
 242                 git commit-graph write --reachable --split --max-commits=1 &&
 243                 test_line_count = 1 $graphdir/commit-graph-chain &&
 244                 ls $graphdir/graph-*.graph >graph-files &&
 245                 test_line_count = 1 graph-files
 246         )
 247 '
 248
 249 test_expect_success 'remove commit-graph-chain file after flattening' '
 250         git clone . flatten &&
 251         (
 252                 cd flatten &&
 253                 test_line_count = 2 $graphdir/commit-graph-chain &&
 254                 git commit-graph write --reachable &&
 255                 test_path_is_missing $graphdir/commit-graph-chain &&
 256                 ls $graphdir >graph-files &&
 257                 test_line_count = 0 graph-files
 258         )
 259 '
 260
 261 corrupt_file() {
 262         file=$1
 263         pos=$2
 264         data="${3:-\0}"
 265         chmod a+w "$file" &&
 266         printf "$data" | dd of="$file" bs=1 seek="$pos" conv=notrunc
 267 }
 268
 269 test_expect_success 'verify hashes along chain, even in shallow' '
 270         git clone --no-hardlinks . verify &&
 271         (
 272                 cd verify &&
 273                 git commit-graph verify &&
 274                 base_file=$graphdir/graph-$(head -n 1 $graphdir/commit-graph-chain).graph &&
 275                 corrupt_file "$base_file" $(test_oid shallow) "\01" &&
 276                 test_must_fail git commit-graph verify --shallow 2>test_err &&
 277                 grep -v "^+" test_err >err &&
 278                 test_i18ngrep "incorrect checksum" err
 279         )
 280 '
 281
 282 test_expect_success 'verify --shallow does not check base contents' '
 283         git clone --no-hardlinks . verify-shallow &&
 284         (
 285                 cd verify-shallow &&
 286                 git commit-graph verify &&
 287                 base_file=$graphdir/graph-$(head -n 1 $graphdir/commit-graph-chain).graph &&
 288                 corrupt_file "$base_file" 1000 "\01" &&
 289                 git commit-graph verify --shallow &&
 290                 test_must_fail git commit-graph verify 2>test_err &&
 291                 grep -v "^+" test_err >err &&
 292                 test_i18ngrep "incorrect checksum" err
 293         )
 294 '
 295
 296 test_expect_success 'warn on base graph chunk incorrect' '
 297         git clone --no-hardlinks . base-chunk &&
 298         (
 299                 cd base-chunk &&
 300                 git commit-graph verify &&
 301                 base_file=$graphdir/graph-$(tail -n 1 $graphdir/commit-graph-chain).graph &&
 302                 corrupt_file "$base_file" $(test_oid base) "\01" &&
 303                 git commit-graph verify --shallow 2>test_err &&
 304                 grep -v "^+" test_err >err &&
 305                 test_i18ngrep "commit-graph chain does not match" err
 306         )
 307 '
 308
 309 test_expect_success 'verify after commit-graph-chain corruption' '
 310         git clone --no-hardlinks . verify-chain &&
 311         (
 312                 cd verify-chain &&
 313                 corrupt_file "$graphdir/commit-graph-chain" 60 "G" &&
 314                 git commit-graph verify 2>test_err &&
 315                 grep -v "^+" test_err >err &&
 316                 test_i18ngrep "invalid commit-graph chain" err &&
 317                 corrupt_file "$graphdir/commit-graph-chain" 60 "A" &&
 318                 git commit-graph verify 2>test_err &&
 319                 grep -v "^+" test_err >err &&
 320                 test_i18ngrep "unable to find all commit-graph files" err
 321         )
 322 '
 323
 324 test_expect_success 'verify across alternates' '
 325         git clone --no-hardlinks . verify-alt &&
 326         (
 327                 cd verify-alt &&
 328                 rm -rf $graphdir &&
 329                 altdir="$(pwd)/../.git/objects" &&
 330                 echo "$altdir" >.git/objects/info/alternates &&
 331                 git commit-graph verify --object-dir="$altdir/" &&
 332                 test_commit extra &&
 333                 git commit-graph write --reachable --split &&
 334                 tip_file=$graphdir/graph-$(tail -n 1 $graphdir/commit-graph-chain).graph &&
 335                 corrupt_file "$tip_file" 100 "\01" &&
 336                 test_must_fail git commit-graph verify --shallow 2>test_err &&
 337                 grep -v "^+" test_err >err &&
 338                 test_i18ngrep "commit-graph has incorrect fanout value" err
 339         )
 340 '
 341
 342 test_expect_success 'add octopus merge' '
 343         git reset --hard commits/10 &&
 344         git merge commits/3 commits/4 &&
 345         git branch merge/octopus &&
 346         git commit-graph write --reachable --split &&
 347         git commit-graph verify --progress 2>err &&
 348         test_line_count = 3 err &&
 349         test_i18ngrep ! warning err &&
 350         test_line_count = 3 $graphdir/commit-graph-chain
 351 '
 352
 353 graph_git_behavior 'graph exists' merge/octopus commits/12
 354
 355 test_expect_success 'split across alternate where alternate is not split' '
 356         git commit-graph write --reachable &&
 357         test_path_is_file .git/objects/info/commit-graph &&
 358         cp .git/objects/info/commit-graph . &&
 359         git clone --no-hardlinks . alt-split &&
 360         (
 361                 cd alt-split &&
 362                 rm -f .git/objects/info/commit-graph &&
 363                 echo "$(pwd)"/../.git/objects >.git/objects/info/alternates &&
 364                 test_commit 18 &&
 365                 git commit-graph write --reachable --split &&
 366                 test_line_count = 1 $graphdir/commit-graph-chain
 367         ) &&
 368         test_cmp commit-graph .git/objects/info/commit-graph
 369 '
 370
 371 test_expect_success '--split=no-merge always writes an incremental' '
 372         test_when_finished rm -rf a b &&
 373         rm -rf $graphdir $infodir/commit-graph &&
 374         git reset --hard commits/2 &&
 375         git rev-list HEAD~1 >a &&
 376         git rev-list HEAD >b &&
 377         git commit-graph write --split --stdin-commits <a &&
 378         git commit-graph write --split=no-merge --stdin-commits <b &&
 379         test_line_count = 2 $graphdir/commit-graph-chain
 380 '
 381
 382 test_expect_success '--split=replace replaces the chain' '
 383         rm -rf $graphdir $infodir/commit-graph &&
 384         git reset --hard commits/3 &&
 385         git rev-list -1 HEAD~2 >a &&
 386         git rev-list -1 HEAD~1 >b &&
 387         git rev-list -1 HEAD >c &&
 388         git commit-graph write --split=no-merge --stdin-commits <a &&
 389         git commit-graph write --split=no-merge --stdin-commits <b &&
 390         git commit-graph write --split=no-merge --stdin-commits <c &&
 391         test_line_count = 3 $graphdir/commit-graph-chain &&
 392         git commit-graph write --stdin-commits --split=replace <b &&
 393         test_path_is_missing $infodir/commit-graph &&
 394         test_path_is_file $graphdir/commit-graph-chain &&
 395         ls $graphdir/graph-*.graph >graph-files &&
 396         test_line_count = 1 graph-files &&
 397         verify_chain_files_exist $graphdir &&
 398         graph_read_expect 2
 399 '
 400
 401 test_expect_success ULIMIT_FILE_DESCRIPTORS 'handles file descriptor exhaustion' '
 402         git init ulimit &&
 403         (
 404                 cd ulimit &&
 405                 for i in $(test_seq 64)
 406                 do
 407                         test_commit $i &&
 408                         run_with_limited_open_files test_might_fail git commit-graph write \
 409                                 --split=no-merge --reachable || return 1
 410                 done
 411         )
 412 '
 413
 414 while read mode modebits
 415 do
 416         test_expect_success POSIXPERM "split commit-graph respects core.sharedrepository $mode" '
 417                 rm -rf $graphdir $infodir/commit-graph &&
 418                 git reset --hard commits/1 &&
 419                 test_config core.sharedrepository "$mode" &&
 420                 git commit-graph write --split --reachable &&
 421                 ls $graphdir/graph-*.graph >graph-files &&
 422                 test_line_count = 1 graph-files &&
 423                 echo "$modebits" >expect &&
 424                 test_modebits $graphdir/graph-*.graph >actual &&
 425                 test_cmp expect actual &&
 426                 test_modebits $graphdir/commit-graph-chain >actual &&
 427                 test_cmp expect actual
 428         '
 429 done <<\EOF
 430 0666 -r--r--r--
 431 0600 -r--------
 432 EOF
 433
 434 test_expect_success '--split=replace with partial Bloom data' '
 435         rm -rf $graphdir $infodir/commit-graph &&
 436         git reset --hard commits/3 &&
 437         git rev-list -1 HEAD~2 >a &&
 438         git rev-list -1 HEAD~1 >b &&
 439         git commit-graph write --split=no-merge --stdin-commits --changed-paths <a &&
 440         git commit-graph write --split=no-merge --stdin-commits <b &&
 441         git commit-graph write --split=replace --stdin-commits --changed-paths <c &&
 442         ls $graphdir/graph-*.graph >graph-files &&
 443         test_line_count = 1 graph-files &&
 444         verify_chain_files_exist $graphdir
 445 '
 446
 447 test_expect_success 'prevent regression for duplicate commits across layers' '
 448         git init dup &&
 449         git -C dup commit --allow-empty -m one &&
 450         git -C dup -c core.commitGraph=false commit-graph write --split=no-merge --reachable 2>err &&
 451         test_i18ngrep "attempting to write a commit-graph" err &&
 452         git -C dup commit-graph write --split=no-merge --reachable &&
 453         git -C dup commit --allow-empty -m two &&
 454         git -C dup commit-graph write --split=no-merge --reachable &&
 455         git -C dup commit --allow-empty -m three &&
 456         git -C dup commit-graph write --split --reachable &&
 457         git -C dup commit-graph verify
 458 '
 459
 460 NUM_FIRST_LAYER_COMMITS=64
 461 NUM_SECOND_LAYER_COMMITS=16
 462 NUM_THIRD_LAYER_COMMITS=7
 463 NUM_FOURTH_LAYER_COMMITS=8
 464 NUM_FIFTH_LAYER_COMMITS=16
 465 SECOND_LAYER_SEQUENCE_START=$(($NUM_FIRST_LAYER_COMMITS + 1))
 466 SECOND_LAYER_SEQUENCE_END=$(($SECOND_LAYER_SEQUENCE_START + $NUM_SECOND_LAYER_COMMITS - 1))
 467 THIRD_LAYER_SEQUENCE_START=$(($SECOND_LAYER_SEQUENCE_END + 1))
 468 THIRD_LAYER_SEQUENCE_END=$(($THIRD_LAYER_SEQUENCE_START + $NUM_THIRD_LAYER_COMMITS - 1))
 469 FOURTH_LAYER_SEQUENCE_START=$(($THIRD_LAYER_SEQUENCE_END + 1))
 470 FOURTH_LAYER_SEQUENCE_END=$(($FOURTH_LAYER_SEQUENCE_START + $NUM_FOURTH_LAYER_COMMITS - 1))
 471 FIFTH_LAYER_SEQUENCE_START=$(($FOURTH_LAYER_SEQUENCE_END + 1))
 472 FIFTH_LAYER_SEQUENCE_END=$(($FIFTH_LAYER_SEQUENCE_START + $NUM_FIFTH_LAYER_COMMITS - 1))
 473
 474 # Current split graph chain:
 475 #
 476 #     16 commits (No GDAT)
 477 # ------------------------
 478 #     64 commits (GDAT)
 479 #
 480 test_expect_success 'setup repo for mixed generation commit-graph-chain' '
 481         graphdir=".git/objects/info/commit-graphs" &&
 482         test_oid_cache <<-EOF &&
 483         oid_version sha1:1
 484         oid_version sha256:2
 485         EOF
 486         git init mixed &&
 487         (
 488                 cd mixed &&
 489                 git config core.commitGraph true &&
 490                 git config gc.writeCommitGraph false &&
 491                 for i in $(test_seq $NUM_FIRST_LAYER_COMMITS)
 492                 do
 493                         test_commit $i &&
 494                         git branch commits/$i || return 1
 495                 done &&
 496                 git -c commitGraph.generationVersion=2 commit-graph write --reachable --split &&
 497                 graph_read_expect $NUM_FIRST_LAYER_COMMITS &&
 498                 test_line_count = 1 $graphdir/commit-graph-chain &&
 499                 for i in $(test_seq $SECOND_LAYER_SEQUENCE_START $SECOND_LAYER_SEQUENCE_END)
 500                 do
 501                         test_commit $i &&
 502                         git branch commits/$i || return 1
 503                 done &&
 504                 git -c commitGraph.generationVersion=1 commit-graph write --reachable --split=no-merge &&
 505                 test_line_count = 2 $graphdir/commit-graph-chain &&
 506                 test-tool read-graph >output &&
 507                 cat >expect <<-EOF &&
 508                 header: 43475048 1 $(test_oid oid_version) 4 1
 509                 num_commits: $NUM_SECOND_LAYER_COMMITS
 510                 chunks: oid_fanout oid_lookup commit_metadata
 511                 EOF
 512                 test_cmp expect output &&
 513                 git commit-graph verify &&
 514                 cat $graphdir/commit-graph-chain
 515         )
 516 '
 517
 518 # The new layer will be added without generation data chunk as it was not
 519 # present on the layer underneath it.
 520 #
 521 #      7 commits (No GDAT)
 522 # ------------------------
 523 #     16 commits (No GDAT)
 524 # ------------------------
 525 #     64 commits (GDAT)
 526 #
 527 test_expect_success 'do not write generation data chunk if not present on existing tip' '
 528         git clone mixed mixed-no-gdat &&
 529         (
 530                 cd mixed-no-gdat &&
 531                 for i in $(test_seq $THIRD_LAYER_SEQUENCE_START $THIRD_LAYER_SEQUENCE_END)
 532                 do
 533                         test_commit $i &&
 534                         git branch commits/$i || return 1
 535                 done &&
 536                 git commit-graph write --reachable --split=no-merge &&
 537                 test_line_count = 3 $graphdir/commit-graph-chain &&
 538                 test-tool read-graph >output &&
 539                 cat >expect <<-EOF &&
 540                 header: 43475048 1 $(test_oid oid_version) 4 2
 541                 num_commits: $NUM_THIRD_LAYER_COMMITS
 542                 chunks: oid_fanout oid_lookup commit_metadata
 543                 EOF
 544                 test_cmp expect output &&
 545                 git commit-graph verify
 546         )
 547 '
 548
 549 # Number of commits in each layer of the split-commit graph before merge:
 550 #
 551 #      8 commits (No GDAT)
 552 # ------------------------
 553 #      7 commits (No GDAT)
 554 # ------------------------
 555 #     16 commits (No GDAT)
 556 # ------------------------
 557 #     64 commits (GDAT)
 558 #
 559 # The top two layers are merged and do not have generation data chunk as layer below them does
 560 # not have generation data chunk.
 561 #
 562 #     15 commits (No GDAT)
 563 # ------------------------
 564 #     16 commits (No GDAT)
 565 # ------------------------
 566 #     64 commits (GDAT)
 567 #
 568 test_expect_success 'do not write generation data chunk if the topmost remaining layer does not have generation data chunk' '
 569         git clone mixed-no-gdat mixed-merge-no-gdat &&
 570         (
 571                 cd mixed-merge-no-gdat &&
 572                 for i in $(test_seq $FOURTH_LAYER_SEQUENCE_START $FOURTH_LAYER_SEQUENCE_END)
 573                 do
 574                         test_commit $i &&
 575                         git branch commits/$i || return 1
 576                 done &&
 577                 git commit-graph write --reachable --split --size-multiple 1 &&
 578                 test_line_count = 3 $graphdir/commit-graph-chain &&
 579                 test-tool read-graph >output &&
 580                 cat >expect <<-EOF &&
 581                 header: 43475048 1 $(test_oid oid_version) 4 2
 582                 num_commits: $(($NUM_THIRD_LAYER_COMMITS + $NUM_FOURTH_LAYER_COMMITS))
 583                 chunks: oid_fanout oid_lookup commit_metadata
 584                 EOF
 585                 test_cmp expect output &&
 586                 git commit-graph verify
 587         )
 588 '
 589
 590 # Number of commits in each layer of the split-commit graph before merge:
 591 #
 592 #     16 commits (No GDAT)
 593 # ------------------------
 594 #     15 commits (No GDAT)
 595 # ------------------------
 596 #     16 commits (No GDAT)
 597 # ------------------------
 598 #     64 commits (GDAT)
 599 #
 600 # The top three layers are merged and has generation data chunk as the topmost remaining layer
 601 # has generation data chunk.
 602 #
 603 #     47 commits (GDAT)
 604 # ------------------------
 605 #     64 commits (GDAT)
 606 #
 607 test_expect_success 'write generation data chunk if topmost remaining layer has generation data chunk' '
 608         git clone mixed-merge-no-gdat mixed-merge-gdat &&
 609         (
 610                 cd mixed-merge-gdat &&
 611                 for i in $(test_seq $FIFTH_LAYER_SEQUENCE_START $FIFTH_LAYER_SEQUENCE_END)
 612                 do
 613                         test_commit $i &&
 614                         git branch commits/$i || return 1
 615                 done &&
 616                 git commit-graph write --reachable --split --size-multiple 1 &&
 617                 test_line_count = 2 $graphdir/commit-graph-chain &&
 618                 test-tool read-graph >output &&
 619                 cat >expect <<-EOF &&
 620                 header: 43475048 1 $(test_oid oid_version) 5 1
 621                 num_commits: $(($NUM_SECOND_LAYER_COMMITS + $NUM_THIRD_LAYER_COMMITS + $NUM_FOURTH_LAYER_COMMITS + $NUM_FIFTH_LAYER_COMMITS))
 622                 chunks: oid_fanout oid_lookup commit_metadata generation_data
 623                 EOF
 624                 test_cmp expect output
 625         )
 626 '
 627
 628 test_expect_success 'write generation data chunk when commit-graph chain is replaced' '
 629         git clone mixed mixed-replace &&
 630         (
 631                 cd mixed-replace &&
 632                 git commit-graph write --reachable --split=replace &&
 633                 test_path_is_file $graphdir/commit-graph-chain &&
 634                 test_line_count = 1 $graphdir/commit-graph-chain &&
 635                 verify_chain_files_exist $graphdir &&
 636                 graph_read_expect $(($NUM_FIRST_LAYER_COMMITS + $NUM_SECOND_LAYER_COMMITS)) &&
 637                 git commit-graph verify
 638         )
 639 '
 640
 641 test_done