t/t3030-merge-recursive.sh

   1 #!/bin/sh
   2
   3 test_description='merge-recursive backend test'
   4
   5 . ./test-lib.sh
   6
   7 test_expect_success 'setup 1' '
   8
   9         echo hello >a &&
  10         o0=$(git hash-object a) &&
  11         cp a b &&
  12         cp a c &&
  13         mkdir d &&
  14         cp a d/e &&
  15
  16         test_tick &&
  17         git add a b c d/e &&
  18         git commit -m initial &&
  19         c0=$(git rev-parse --verify HEAD) &&
  20         git branch side &&
  21         git branch df-1 &&
  22         git branch df-2 &&
  23         git branch df-3 &&
  24         git branch remove &&
  25         git branch submod &&
  26         git branch copy &&
  27         git branch rename &&
  28         git branch rename-ln &&
  29
  30         echo hello >>a &&
  31         cp a d/e &&
  32         o1=$(git hash-object a) &&
  33
  34         git add a d/e &&
  35
  36         test_tick &&
  37         git commit -m "master modifies a and d/e" &&
  38         c1=$(git rev-parse --verify HEAD) &&
  39         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
  40         (
  41                 echo "100644 blob $o1   a"
  42                 echo "100644 blob $o0   b"
  43                 echo "100644 blob $o0   c"
  44                 echo "100644 blob $o1   d/e"
  45                 echo "100644 $o1 0      a"
  46                 echo "100644 $o0 0      b"
  47                 echo "100644 $o0 0      c"
  48                 echo "100644 $o1 0      d/e"
  49         ) >expected &&
  50         test_cmp expected actual
  51 '
  52
  53 test_expect_success 'setup 2' '
  54
  55         rm -rf [abcd] &&
  56         git checkout side &&
  57         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
  58         (
  59                 echo "100644 blob $o0   a"
  60                 echo "100644 blob $o0   b"
  61                 echo "100644 blob $o0   c"
  62                 echo "100644 blob $o0   d/e"
  63                 echo "100644 $o0 0      a"
  64                 echo "100644 $o0 0      b"
  65                 echo "100644 $o0 0      c"
  66                 echo "100644 $o0 0      d/e"
  67         ) >expected &&
  68         test_cmp expected actual &&
  69
  70         echo goodbye >>a &&
  71         o2=$(git hash-object a) &&
  72
  73         git add a &&
  74
  75         test_tick &&
  76         git commit -m "side modifies a" &&
  77         c2=$(git rev-parse --verify HEAD) &&
  78         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
  79         (
  80                 echo "100644 blob $o2   a"
  81                 echo "100644 blob $o0   b"
  82                 echo "100644 blob $o0   c"
  83                 echo "100644 blob $o0   d/e"
  84                 echo "100644 $o2 0      a"
  85                 echo "100644 $o0 0      b"
  86                 echo "100644 $o0 0      c"
  87                 echo "100644 $o0 0      d/e"
  88         ) >expected &&
  89         test_cmp expected actual
  90 '
  91
  92 test_expect_success 'setup 3' '
  93
  94         rm -rf [abcd] &&
  95         git checkout df-1 &&
  96         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
  97         (
  98                 echo "100644 blob $o0   a"
  99                 echo "100644 blob $o0   b"
 100                 echo "100644 blob $o0   c"
 101                 echo "100644 blob $o0   d/e"
 102                 echo "100644 $o0 0      a"
 103                 echo "100644 $o0 0      b"
 104                 echo "100644 $o0 0      c"
 105                 echo "100644 $o0 0      d/e"
 106         ) >expected &&
 107         test_cmp expected actual &&
 108
 109         rm -f b && mkdir b && echo df-1 >b/c && git add b/c &&
 110         o3=$(git hash-object b/c) &&
 111
 112         test_tick &&
 113         git commit -m "df-1 makes b/c" &&
 114         c3=$(git rev-parse --verify HEAD) &&
 115         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 116         (
 117                 echo "100644 blob $o0   a"
 118                 echo "100644 blob $o3   b/c"
 119                 echo "100644 blob $o0   c"
 120                 echo "100644 blob $o0   d/e"
 121                 echo "100644 $o0 0      a"
 122                 echo "100644 $o3 0      b/c"
 123                 echo "100644 $o0 0      c"
 124                 echo "100644 $o0 0      d/e"
 125         ) >expected &&
 126         test_cmp expected actual
 127 '
 128
 129 test_expect_success 'setup 4' '
 130
 131         rm -rf [abcd] &&
 132         git checkout df-2 &&
 133         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 134         (
 135                 echo "100644 blob $o0   a"
 136                 echo "100644 blob $o0   b"
 137                 echo "100644 blob $o0   c"
 138                 echo "100644 blob $o0   d/e"
 139                 echo "100644 $o0 0      a"
 140                 echo "100644 $o0 0      b"
 141                 echo "100644 $o0 0      c"
 142                 echo "100644 $o0 0      d/e"
 143         ) >expected &&
 144         test_cmp expected actual &&
 145
 146         rm -f a && mkdir a && echo df-2 >a/c && git add a/c &&
 147         o4=$(git hash-object a/c) &&
 148
 149         test_tick &&
 150         git commit -m "df-2 makes a/c" &&
 151         c4=$(git rev-parse --verify HEAD) &&
 152         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 153         (
 154                 echo "100644 blob $o4   a/c"
 155                 echo "100644 blob $o0   b"
 156                 echo "100644 blob $o0   c"
 157                 echo "100644 blob $o0   d/e"
 158                 echo "100644 $o4 0      a/c"
 159                 echo "100644 $o0 0      b"
 160                 echo "100644 $o0 0      c"
 161                 echo "100644 $o0 0      d/e"
 162         ) >expected &&
 163         test_cmp expected actual
 164 '
 165
 166 test_expect_success 'setup 5' '
 167
 168         rm -rf [abcd] &&
 169         git checkout remove &&
 170         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 171         (
 172                 echo "100644 blob $o0   a"
 173                 echo "100644 blob $o0   b"
 174                 echo "100644 blob $o0   c"
 175                 echo "100644 blob $o0   d/e"
 176                 echo "100644 $o0 0      a"
 177                 echo "100644 $o0 0      b"
 178                 echo "100644 $o0 0      c"
 179                 echo "100644 $o0 0      d/e"
 180         ) >expected &&
 181         test_cmp expected actual &&
 182
 183         rm -f b &&
 184         echo remove-conflict >a &&
 185
 186         git add a &&
 187         git rm b &&
 188         o5=$(git hash-object a) &&
 189
 190         test_tick &&
 191         git commit -m "remove removes b and modifies a" &&
 192         c5=$(git rev-parse --verify HEAD) &&
 193         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 194         (
 195                 echo "100644 blob $o5   a"
 196                 echo "100644 blob $o0   c"
 197                 echo "100644 blob $o0   d/e"
 198                 echo "100644 $o5 0      a"
 199                 echo "100644 $o0 0      c"
 200                 echo "100644 $o0 0      d/e"
 201         ) >expected &&
 202         test_cmp expected actual
 203
 204 '
 205
 206 test_expect_success 'setup 6' '
 207
 208         rm -rf [abcd] &&
 209         git checkout df-3 &&
 210         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 211         (
 212                 echo "100644 blob $o0   a"
 213                 echo "100644 blob $o0   b"
 214                 echo "100644 blob $o0   c"
 215                 echo "100644 blob $o0   d/e"
 216                 echo "100644 $o0 0      a"
 217                 echo "100644 $o0 0      b"
 218                 echo "100644 $o0 0      c"
 219                 echo "100644 $o0 0      d/e"
 220         ) >expected &&
 221         test_cmp expected actual &&
 222
 223         rm -fr d && echo df-3 >d && git add d &&
 224         o6=$(git hash-object d) &&
 225
 226         test_tick &&
 227         git commit -m "df-3 makes d" &&
 228         c6=$(git rev-parse --verify HEAD) &&
 229         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 230         (
 231                 echo "100644 blob $o0   a"
 232                 echo "100644 blob $o0   b"
 233                 echo "100644 blob $o0   c"
 234                 echo "100644 blob $o6   d"
 235                 echo "100644 $o0 0      a"
 236                 echo "100644 $o0 0      b"
 237                 echo "100644 $o0 0      c"
 238                 echo "100644 $o6 0      d"
 239         ) >expected &&
 240         test_cmp expected actual
 241 '
 242
 243 test_expect_success 'setup 7' '
 244
 245         git checkout submod &&
 246         git rm d/e &&
 247         test_tick &&
 248         git commit -m "remove d/e" &&
 249         git update-index --add --cacheinfo 160000 $c1 d &&
 250         test_tick &&
 251         git commit -m "make d/ a submodule"
 252 '
 253
 254 test_expect_success 'setup 8' '
 255         git checkout rename &&
 256         git mv a e &&
 257         git add e &&
 258         test_tick &&
 259         git commit -m "rename a->e" &&
 260         c7=$(git rev-parse --verify HEAD) &&
 261         git checkout rename-ln &&
 262         git mv a e &&
 263         test_ln_s_add e a &&
 264         test_tick &&
 265         git commit -m "rename a->e, symlink a->e" &&
 266         oln=$(printf e | git hash-object --stdin)
 267 '
 268
 269 test_expect_success 'setup 9' '
 270         git checkout copy &&
 271         cp a e &&
 272         git add e &&
 273         test_tick &&
 274         git commit -m "copy a->e"
 275 '
 276
 277 test_expect_success 'merge-recursive simple' '
 278
 279         rm -fr [abcd] &&
 280         git checkout -f "$c2" &&
 281
 282         test_expect_code 1 git merge-recursive "$c0" -- "$c2" "$c1"
 283 '
 284
 285 test_expect_success 'merge-recursive result' '
 286
 287         git ls-files -s >actual &&
 288         (
 289                 echo "100644 $o0 1      a"
 290                 echo "100644 $o2 2      a"
 291                 echo "100644 $o1 3      a"
 292                 echo "100644 $o0 0      b"
 293                 echo "100644 $o0 0      c"
 294                 echo "100644 $o1 0      d/e"
 295         ) >expected &&
 296         test_cmp expected actual
 297
 298 '
 299
 300 test_expect_success 'fail if the index has unresolved entries' '
 301
 302         rm -fr [abcd] &&
 303         git checkout -f "$c1" &&
 304
 305         test_must_fail git merge "$c5" &&
 306         test_must_fail git merge "$c5" 2> out &&
 307         test_i18ngrep "not possible because you have unmerged files" out &&
 308         git add -u &&
 309         test_must_fail git merge "$c5" 2> out &&
 310         test_i18ngrep "You have not concluded your merge" out &&
 311         rm -f .git/MERGE_HEAD &&
 312         test_must_fail git merge "$c5" 2> out &&
 313         test_i18ngrep "Your local changes to the following files would be overwritten by merge:" out
 314 '
 315
 316 test_expect_success 'merge-recursive remove conflict' '
 317
 318         rm -fr [abcd] &&
 319         git checkout -f "$c1" &&
 320
 321         test_expect_code 1 git merge-recursive "$c0" -- "$c1" "$c5"
 322 '
 323
 324 test_expect_success 'merge-recursive remove conflict' '
 325
 326         git ls-files -s >actual &&
 327         (
 328                 echo "100644 $o0 1      a"
 329                 echo "100644 $o1 2      a"
 330                 echo "100644 $o5 3      a"
 331                 echo "100644 $o0 0      c"
 332                 echo "100644 $o1 0      d/e"
 333         ) >expected &&
 334         test_cmp expected actual
 335
 336 '
 337
 338 test_expect_success 'merge-recursive d/f simple' '
 339         rm -fr [abcd] &&
 340         git reset --hard &&
 341         git checkout -f "$c1" &&
 342
 343         git merge-recursive "$c0" -- "$c1" "$c3"
 344 '
 345
 346 test_expect_success 'merge-recursive result' '
 347
 348         git ls-files -s >actual &&
 349         (
 350                 echo "100644 $o1 0      a"
 351                 echo "100644 $o3 0      b/c"
 352                 echo "100644 $o0 0      c"
 353                 echo "100644 $o1 0      d/e"
 354         ) >expected &&
 355         test_cmp expected actual
 356
 357 '
 358
 359 test_expect_success 'merge-recursive d/f conflict' '
 360
 361         rm -fr [abcd] &&
 362         git reset --hard &&
 363         git checkout -f "$c1" &&
 364
 365         test_expect_code 1 git merge-recursive "$c0" -- "$c1" "$c4"
 366 '
 367
 368 test_expect_success 'merge-recursive d/f conflict result' '
 369
 370         git ls-files -s >actual &&
 371         (
 372                 echo "100644 $o0 1      a"
 373                 echo "100644 $o1 2      a"
 374                 echo "100644 $o4 0      a/c"
 375                 echo "100644 $o0 0      b"
 376                 echo "100644 $o0 0      c"
 377                 echo "100644 $o1 0      d/e"
 378         ) >expected &&
 379         test_cmp expected actual
 380
 381 '
 382
 383 test_expect_success 'merge-recursive d/f conflict the other way' '
 384
 385         rm -fr [abcd] &&
 386         git reset --hard &&
 387         git checkout -f "$c4" &&
 388
 389         test_expect_code 1 git merge-recursive "$c0" -- "$c4" "$c1"
 390 '
 391
 392 test_expect_success 'merge-recursive d/f conflict result the other way' '
 393
 394         git ls-files -s >actual &&
 395         (
 396                 echo "100644 $o0 1      a"
 397                 echo "100644 $o1 3      a"
 398                 echo "100644 $o4 0      a/c"
 399                 echo "100644 $o0 0      b"
 400                 echo "100644 $o0 0      c"
 401                 echo "100644 $o1 0      d/e"
 402         ) >expected &&
 403         test_cmp expected actual
 404
 405 '
 406
 407 test_expect_success 'merge-recursive d/f conflict' '
 408
 409         rm -fr [abcd] &&
 410         git reset --hard &&
 411         git checkout -f "$c1" &&
 412
 413         test_expect_code 1 git merge-recursive "$c0" -- "$c1" "$c6"
 414 '
 415
 416 test_expect_success 'merge-recursive d/f conflict result' '
 417
 418         git ls-files -s >actual &&
 419         (
 420                 echo "100644 $o1 0      a"
 421                 echo "100644 $o0 0      b"
 422                 echo "100644 $o0 0      c"
 423                 echo "100644 $o6 3      d"
 424                 echo "100644 $o0 1      d/e"
 425                 echo "100644 $o1 2      d/e"
 426         ) >expected &&
 427         test_cmp expected actual
 428
 429 '
 430
 431 test_expect_success 'merge-recursive d/f conflict' '
 432
 433         rm -fr [abcd] &&
 434         git reset --hard &&
 435         git checkout -f "$c6" &&
 436
 437         test_expect_code 1 git merge-recursive "$c0" -- "$c6" "$c1"
 438 '
 439
 440 test_expect_success 'merge-recursive d/f conflict result' '
 441
 442         git ls-files -s >actual &&
 443         (
 444                 echo "100644 $o1 0      a"
 445                 echo "100644 $o0 0      b"
 446                 echo "100644 $o0 0      c"
 447                 echo "100644 $o6 2      d"
 448                 echo "100644 $o0 1      d/e"
 449                 echo "100644 $o1 3      d/e"
 450         ) >expected &&
 451         test_cmp expected actual
 452
 453 '
 454
 455 test_expect_success 'reset and 3-way merge' '
 456
 457         git reset --hard "$c2" &&
 458         git read-tree -m "$c0" "$c2" "$c1"
 459
 460 '
 461
 462 test_expect_success 'reset and bind merge' '
 463
 464         git reset --hard master &&
 465         git read-tree --prefix=M/ master &&
 466         git ls-files -s >actual &&
 467         (
 468                 echo "100644 $o1 0      M/a"
 469                 echo "100644 $o0 0      M/b"
 470                 echo "100644 $o0 0      M/c"
 471                 echo "100644 $o1 0      M/d/e"
 472                 echo "100644 $o1 0      a"
 473                 echo "100644 $o0 0      b"
 474                 echo "100644 $o0 0      c"
 475                 echo "100644 $o1 0      d/e"
 476         ) >expected &&
 477         test_cmp expected actual &&
 478
 479         git read-tree --prefix=a1/ master &&
 480         git ls-files -s >actual &&
 481         (
 482                 echo "100644 $o1 0      M/a"
 483                 echo "100644 $o0 0      M/b"
 484                 echo "100644 $o0 0      M/c"
 485                 echo "100644 $o1 0      M/d/e"
 486                 echo "100644 $o1 0      a"
 487                 echo "100644 $o1 0      a1/a"
 488                 echo "100644 $o0 0      a1/b"
 489                 echo "100644 $o0 0      a1/c"
 490                 echo "100644 $o1 0      a1/d/e"
 491                 echo "100644 $o0 0      b"
 492                 echo "100644 $o0 0      c"
 493                 echo "100644 $o1 0      d/e"
 494         ) >expected &&
 495         test_cmp expected actual &&
 496
 497         git read-tree --prefix=z/ master &&
 498         git ls-files -s >actual &&
 499         (
 500                 echo "100644 $o1 0      M/a"
 501                 echo "100644 $o0 0      M/b"
 502                 echo "100644 $o0 0      M/c"
 503                 echo "100644 $o1 0      M/d/e"
 504                 echo "100644 $o1 0      a"
 505                 echo "100644 $o1 0      a1/a"
 506                 echo "100644 $o0 0      a1/b"
 507                 echo "100644 $o0 0      a1/c"
 508                 echo "100644 $o1 0      a1/d/e"
 509                 echo "100644 $o0 0      b"
 510                 echo "100644 $o0 0      c"
 511                 echo "100644 $o1 0      d/e"
 512                 echo "100644 $o1 0      z/a"
 513                 echo "100644 $o0 0      z/b"
 514                 echo "100644 $o0 0      z/c"
 515                 echo "100644 $o1 0      z/d/e"
 516         ) >expected &&
 517         test_cmp expected actual
 518
 519 '
 520
 521 test_expect_success 'merge-recursive w/ empty work tree - ours has rename' '
 522         (
 523                 GIT_WORK_TREE="$PWD/ours-has-rename-work" &&
 524                 export GIT_WORK_TREE &&
 525                 GIT_INDEX_FILE="$PWD/ours-has-rename-index" &&
 526                 export GIT_INDEX_FILE &&
 527                 mkdir "$GIT_WORK_TREE" &&
 528                 git read-tree -i -m $c7 &&
 529                 git update-index --ignore-missing --refresh &&
 530                 git merge-recursive $c0 -- $c7 $c3 &&
 531                 git ls-files -s >actual-files
 532         ) 2>actual-err &&
 533         >expected-err &&
 534         cat >expected-files <<-EOF &&
 535         100644 $o3 0    b/c
 536         100644 $o0 0    c
 537         100644 $o0 0    d/e
 538         100644 $o0 0    e
 539         EOF
 540         test_cmp expected-files actual-files &&
 541         test_cmp expected-err actual-err
 542 '
 543
 544 test_expect_success 'merge-recursive w/ empty work tree - theirs has rename' '
 545         (
 546                 GIT_WORK_TREE="$PWD/theirs-has-rename-work" &&
 547                 export GIT_WORK_TREE &&
 548                 GIT_INDEX_FILE="$PWD/theirs-has-rename-index" &&
 549                 export GIT_INDEX_FILE &&
 550                 mkdir "$GIT_WORK_TREE" &&
 551                 git read-tree -i -m $c3 &&
 552                 git update-index --ignore-missing --refresh &&
 553                 git merge-recursive $c0 -- $c3 $c7 &&
 554                 git ls-files -s >actual-files
 555         ) 2>actual-err &&
 556         >expected-err &&
 557         cat >expected-files <<-EOF &&
 558         100644 $o3 0    b/c
 559         100644 $o0 0    c
 560         100644 $o0 0    d/e
 561         100644 $o0 0    e
 562         EOF
 563         test_cmp expected-files actual-files &&
 564         test_cmp expected-err actual-err
 565 '
 566
 567 test_expect_success 'merge removes empty directories' '
 568
 569         git reset --hard master &&
 570         git checkout -b rm &&
 571         git rm d/e &&
 572         git commit -mremoved-d/e &&
 573         git checkout master &&
 574         git merge -s recursive rm &&
 575         test_must_fail test -d d
 576 '
 577
 578 test_expect_success 'merge-recursive simple w/submodule' '
 579
 580         git checkout submod &&
 581         git merge remove
 582 '
 583
 584 test_expect_success 'merge-recursive simple w/submodule result' '
 585
 586         git ls-files -s >actual &&
 587         (
 588                 echo "100644 $o5 0      a"
 589                 echo "100644 $o0 0      c"
 590                 echo "160000 $c1 0      d"
 591         ) >expected &&
 592         test_cmp expected actual
 593 '
 594
 595 test_expect_success 'merge-recursive copy vs. rename' '
 596         git checkout -f copy &&
 597         git merge rename &&
 598         ( git ls-tree -r HEAD && git ls-files -s ) >actual &&
 599         (
 600                 echo "100644 blob $o0   b"
 601                 echo "100644 blob $o0   c"
 602                 echo "100644 blob $o0   d/e"
 603                 echo "100644 blob $o0   e"
 604                 echo "100644 $o0 0      b"
 605                 echo "100644 $o0 0      c"
 606                 echo "100644 $o0 0      d/e"
 607                 echo "100644 $o0 0      e"
 608         ) >expected &&
 609         test_cmp expected actual
 610 '
 611
 612 test_expect_failure 'merge-recursive rename vs. rename/symlink' '
 613
 614         git checkout -f rename &&
 615         git merge rename-ln &&
 616         ( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
 617         (
 618                 echo "120000 blob $oln  a"
 619                 echo "100644 blob $o0   b"
 620                 echo "100644 blob $o0   c"
 621                 echo "100644 blob $o0   d/e"
 622                 echo "100644 blob $o0   e"
 623                 echo "120000 $oln 0     a"
 624                 echo "100644 $o0 0      b"
 625                 echo "100644 $o0 0      c"
 626                 echo "100644 $o0 0      d/e"
 627                 echo "100644 $o0 0      e"
 628         ) >expected &&
 629         test_cmp expected actual
 630 '
 631
 632 test_expect_success 'merging with triple rename across D/F conflict' '
 633         git reset --hard HEAD &&
 634         git checkout -b main &&
 635         git rm -rf . &&
 636
 637         echo "just a file" >sub1 &&
 638         mkdir -p sub2 &&
 639         echo content1 >sub2/file1 &&
 640         echo content2 >sub2/file2 &&
 641         echo content3 >sub2/file3 &&
 642         mkdir simple &&
 643         echo base >simple/bar &&
 644         git add -A &&
 645         test_tick &&
 646         git commit -m base &&
 647
 648         git checkout -b other &&
 649         echo more >>simple/bar &&
 650         test_tick &&
 651         git commit -a -m changesimplefile &&
 652
 653         git checkout main &&
 654         git rm sub1 &&
 655         git mv sub2 sub1 &&
 656         test_tick &&
 657         git commit -m changefiletodir &&
 658
 659         test_tick &&
 660         git merge other
 661 '
 662
 663 test_expect_success 'merge-recursive remembers the names of all base trees' '
 664         git reset --hard HEAD &&
 665
 666         # more trees than static slots used by oid_to_hex()
 667         for commit in $c0 $c2 $c4 $c5 $c6 $c7
 668         do
 669                 git rev-parse "$commit^{tree}"
 670         done >trees &&
 671
 672         # ignore the return code -- it only fails because the input is weird
 673         test_must_fail git -c merge.verbosity=5 merge-recursive $(cat trees) -- $c1 $c3 >out &&
 674
 675         # merge-recursive prints in reverse order, but we do not care
 676         sort <trees >expect &&
 677         sed -n "s/^virtual //p" out | sort >actual &&
 678         test_cmp expect actual
 679 '
 680
 681 test_expect_success 'merge-recursive internal merge resolves to the sameness' '
 682         git reset --hard HEAD &&
 683
 684         # We are going to create a history leading to two criss-cross
 685         # branches A and B.  The common ancestor at the bottom, O0,
 686         # has two child commits O1 and O2, both of which will be merge
 687         # base between A and B, like so:
 688         #
 689         #       O1---A
 690         #      /  \ /
 691         #    O0    .
 692         #      \  / \
 693         #       O2---B
 694         #
 695         # The recently added "check to see if the index is different from
 696         # the tree into which something else is getting merged" check must
 697         # NOT kick in when an inner merge between O1 and O2 is made.  Both
 698         # O1 and O2 happen to have the same tree as O0 in this test to
 699         # trigger the bug---whether the inner merge is made by merging O2
 700         # into O1 or O1 into O2, their common ancestor O0 and the branch
 701         # being merged have the same tree.  We should not trigger the "is
 702         # the index dirty?" check in this case.
 703
 704         echo "zero" >file &&
 705         git add file &&
 706         test_tick &&
 707         git commit -m "O0" &&
 708         O0=$(git rev-parse HEAD) &&
 709
 710         test_tick &&
 711         git commit --allow-empty -m "O1" &&
 712         O1=$(git rev-parse HEAD) &&
 713
 714         git reset --hard $O0 &&
 715         test_tick &&
 716         git commit --allow-empty -m "O2" &&
 717         O2=$(git rev-parse HEAD) &&
 718
 719         test_tick &&
 720         git merge -s ours $O1 &&
 721         B=$(git rev-parse HEAD) &&
 722
 723         git reset --hard $O1 &&
 724         test_tick &&
 725         git merge -s ours $O2 &&
 726         A=$(git rev-parse HEAD) &&
 727
 728         git merge $B
 729 '
 730
 731 test_done