3 test_description='git fsck random collection of tests
11 test_expect_success setup '
12 git config gc.auto 0 &&
13 git config i18n.commitencoding ISO-8859-1 &&
14 test_commit A fileA one &&
15 git config --unset i18n.commitencoding &&
16 git checkout HEAD^0 &&
17 test_commit B fileB two &&
19 git reflog expire --expire=now --all
22 test_expect_success 'loose objects borrowed from alternate are not missing' '
27 echo ../../../.git/objects >.git/objects/info/alternates &&
28 test_commit C fileC one &&
29 git fsck --no-dangling >../actual 2>&1
31 test_must_be_empty actual
34 test_expect_success 'HEAD is part of refs, valid objects appear valid' '
35 git fsck >actual 2>&1 &&
36 test_must_be_empty actual
39 # Corruption tests follow. Make sure to remove all traces of the
40 # specific corruption you test afterwards, lest a later test trip over
43 test_expect_success 'setup: helpers for corruption tests' '
46 firsttwo=${1%$remainder} &&
47 echo ".git/objects/$firsttwo/$remainder"
51 rm "$(sha1_file "$1")"
55 test_expect_success 'object with bad sha1' '
56 sha=$(echo blob | git hash-object -w --stdin) &&
57 old=$(echo $sha | sed "s+^..+&/+") &&
58 new=$(dirname $old)/ffffffffffffffffffffffffffffffffffffff &&
59 sha="$(dirname $new)$(basename $new)" &&
60 mv .git/objects/$old .git/objects/$new &&
61 test_when_finished "remove_object $sha" &&
62 git update-index --add --cacheinfo 100644 $sha foo &&
63 test_when_finished "git read-tree -u --reset HEAD" &&
64 tree=$(git write-tree) &&
65 test_when_finished "remove_object $tree" &&
66 cmt=$(echo bogus | git commit-tree $tree) &&
67 test_when_finished "remove_object $cmt" &&
68 git update-ref refs/heads/bogus $cmt &&
69 test_when_finished "git update-ref -d refs/heads/bogus" &&
71 test_must_fail git fsck 2>out &&
73 grep "$sha.*corrupt" out
76 test_expect_success 'branch pointing to non-commit' '
77 git rev-parse HEAD^{tree} >.git/refs/heads/invalid &&
78 test_when_finished "git update-ref -d refs/heads/invalid" &&
79 test_must_fail git fsck 2>out &&
81 grep "not a commit" out
84 test_expect_success 'HEAD link pointing at a funny object' '
85 test_when_finished "mv .git/SAVED_HEAD .git/HEAD" &&
86 mv .git/HEAD .git/SAVED_HEAD &&
87 echo 0000000000000000000000000000000000000000 >.git/HEAD &&
88 # avoid corrupt/broken HEAD from interfering with repo discovery
89 test_must_fail env GIT_DIR=.git git fsck 2>out &&
91 grep "detached HEAD points" out
94 test_expect_success 'HEAD link pointing at a funny place' '
95 test_when_finished "mv .git/SAVED_HEAD .git/HEAD" &&
96 mv .git/HEAD .git/SAVED_HEAD &&
97 echo "ref: refs/funny/place" >.git/HEAD &&
98 # avoid corrupt/broken HEAD from interfering with repo discovery
99 test_must_fail env GIT_DIR=.git git fsck 2>out &&
101 grep "HEAD points to something strange" out
104 test_expect_success 'email without @ is okay' '
105 git cat-file commit HEAD >basis &&
106 sed "s/@/AT/" basis >okay &&
107 new=$(git hash-object -t commit -w --stdin <okay) &&
108 test_when_finished "remove_object $new" &&
109 git update-ref refs/heads/bogus "$new" &&
110 test_when_finished "git update-ref -d refs/heads/bogus" &&
113 ! grep "commit $new" out
116 test_expect_success 'email with embedded > is not okay' '
117 git cat-file commit HEAD >basis &&
118 sed "s/@[a-z]/&>/" basis >bad-email &&
119 new=$(git hash-object -t commit -w --stdin <bad-email) &&
120 test_when_finished "remove_object $new" &&
121 git update-ref refs/heads/bogus "$new" &&
122 test_when_finished "git update-ref -d refs/heads/bogus" &&
123 test_must_fail git fsck 2>out &&
125 grep "error in commit $new" out
128 test_expect_success 'missing < email delimiter is reported nicely' '
129 git cat-file commit HEAD >basis &&
130 sed "s/<//" basis >bad-email-2 &&
131 new=$(git hash-object -t commit -w --stdin <bad-email-2) &&
132 test_when_finished "remove_object $new" &&
133 git update-ref refs/heads/bogus "$new" &&
134 test_when_finished "git update-ref -d refs/heads/bogus" &&
135 test_must_fail git fsck 2>out &&
137 grep "error in commit $new.* - bad name" out
140 test_expect_success 'missing email is reported nicely' '
141 git cat-file commit HEAD >basis &&
142 sed "s/[a-z]* <[^>]*>//" basis >bad-email-3 &&
143 new=$(git hash-object -t commit -w --stdin <bad-email-3) &&
144 test_when_finished "remove_object $new" &&
145 git update-ref refs/heads/bogus "$new" &&
146 test_when_finished "git update-ref -d refs/heads/bogus" &&
147 test_must_fail git fsck 2>out &&
149 grep "error in commit $new.* - missing email" out
152 test_expect_success '> in name is reported' '
153 git cat-file commit HEAD >basis &&
154 sed "s/ </> </" basis >bad-email-4 &&
155 new=$(git hash-object -t commit -w --stdin <bad-email-4) &&
156 test_when_finished "remove_object $new" &&
157 git update-ref refs/heads/bogus "$new" &&
158 test_when_finished "git update-ref -d refs/heads/bogus" &&
159 test_must_fail git fsck 2>out &&
161 grep "error in commit $new" out
165 test_expect_success 'integer overflow in timestamps is reported' '
166 git cat-file commit HEAD >basis &&
167 sed "s/^\\(author .*>\\) [0-9]*/\\1 18446744073709551617/" \
168 <basis >bad-timestamp &&
169 new=$(git hash-object -t commit -w --stdin <bad-timestamp) &&
170 test_when_finished "remove_object $new" &&
171 git update-ref refs/heads/bogus "$new" &&
172 test_when_finished "git update-ref -d refs/heads/bogus" &&
173 test_must_fail git fsck 2>out &&
175 grep "error in commit $new.*integer overflow" out
178 test_expect_success 'commit with NUL in header' '
179 git cat-file commit HEAD >basis &&
180 sed "s/author ./author Q/" <basis | q_to_nul >commit-NUL-header &&
181 new=$(git hash-object -t commit -w --stdin <commit-NUL-header) &&
182 test_when_finished "remove_object $new" &&
183 git update-ref refs/heads/bogus "$new" &&
184 test_when_finished "git update-ref -d refs/heads/bogus" &&
185 test_must_fail git fsck 2>out &&
187 grep "error in commit $new.*unterminated header: NUL at offset" out
190 test_expect_success 'tree object with duplicate entries' '
191 test_when_finished "for i in \$T; do remove_object \$i; done" &&
193 GIT_INDEX_FILE=test-index &&
194 export GIT_INDEX_FILE &&
199 T=$(git write-tree) &&
202 git cat-file tree $T &&
205 git hash-object -w -t tree --stdin
207 test_must_fail git fsck 2>out &&
208 grep "error in tree .*contains duplicate file entries" out
211 test_expect_success 'unparseable tree object' '
212 test_when_finished "git update-ref -d refs/heads/wrong" &&
213 test_when_finished "remove_object \$tree_sha1" &&
214 test_when_finished "remove_object \$commit_sha1" &&
215 tree_sha1=$(printf "100644 \0twenty-bytes-of-junk" | git hash-object -t tree --stdin -w --literally) &&
216 commit_sha1=$(git commit-tree $tree_sha1) &&
217 git update-ref refs/heads/wrong $commit_sha1 &&
218 test_must_fail git fsck 2>out &&
219 test_i18ngrep "error: empty filename in tree entry" out &&
220 test_i18ngrep "$tree_sha1" out &&
221 test_i18ngrep ! "fatal: empty filename in tree entry" out
225 perl -ne 'printf "\\%03o", hex for /../g'
228 test_expect_success 'tree entry with type mismatch' '
229 test_when_finished "remove_object \$blob" &&
230 test_when_finished "remove_object \$tree" &&
231 test_when_finished "remove_object \$commit" &&
232 test_when_finished "git update-ref -d refs/heads/type_mismatch" &&
233 blob=$(echo blob | git hash-object -w --stdin) &&
234 blob_bin=$(echo $blob | hex2oct) &&
236 printf "40000 dir\0${blob_bin}100644 file\0${blob_bin}" |
237 git hash-object -t tree --stdin -w --literally
239 commit=$(git commit-tree $tree) &&
240 git update-ref refs/heads/type_mismatch $commit &&
241 test_must_fail git fsck >out 2>&1 &&
242 test_i18ngrep "is a blob, not a tree" out &&
243 test_i18ngrep ! "dangling blob" out
246 test_expect_success 'tag pointing to nonexistent' '
247 cat >invalid-tag <<-\EOF &&
248 object ffffffffffffffffffffffffffffffffffffffff
251 tagger T A Gger <tagger@example.com> 1234567890 -0000
253 This is an invalid tag.
256 tag=$(git hash-object -t tag -w --stdin <invalid-tag) &&
257 test_when_finished "remove_object $tag" &&
258 echo $tag >.git/refs/tags/invalid &&
259 test_when_finished "git update-ref -d refs/tags/invalid" &&
260 test_must_fail git fsck --tags >out &&
262 grep "broken link" out
265 test_expect_success 'tag pointing to something else than its type' '
266 sha=$(echo blob | git hash-object -w --stdin) &&
267 test_when_finished "remove_object $sha" &&
268 cat >wrong-tag <<-EOF &&
272 tagger T A Gger <tagger@example.com> 1234567890 -0000
274 This is an invalid tag.
277 tag=$(git hash-object -t tag -w --stdin <wrong-tag) &&
278 test_when_finished "remove_object $tag" &&
279 echo $tag >.git/refs/tags/wrong &&
280 test_when_finished "git update-ref -d refs/tags/wrong" &&
281 test_must_fail git fsck --tags
284 test_expect_success 'tag with incorrect tag name & missing tagger' '
285 sha=$(git rev-parse HEAD) &&
286 cat >wrong-tag <<-EOF &&
289 tag wrong name format
291 This is an invalid tag.
294 tag=$(git hash-object -t tag -w --stdin <wrong-tag) &&
295 test_when_finished "remove_object $tag" &&
296 echo $tag >.git/refs/tags/wrong &&
297 test_when_finished "git update-ref -d refs/tags/wrong" &&
298 git fsck --tags 2>out &&
300 cat >expect <<-EOF &&
301 warning in tag $tag: badTagName: invalid '\''tag'\'' name: wrong name format
302 warning in tag $tag: missingTaggerEntry: invalid format - expected '\''tagger'\'' line
307 test_expect_success 'tag with bad tagger' '
308 sha=$(git rev-parse HEAD) &&
309 cat >wrong-tag <<-EOF &&
313 tagger Bad Tagger Name
315 This is an invalid tag.
318 tag=$(git hash-object --literally -t tag -w --stdin <wrong-tag) &&
319 test_when_finished "remove_object $tag" &&
320 echo $tag >.git/refs/tags/wrong &&
321 test_when_finished "git update-ref -d refs/tags/wrong" &&
322 test_must_fail git fsck --tags 2>out &&
323 grep "error in tag .*: invalid author/committer" out
326 test_expect_success 'tag with NUL in header' '
327 sha=$(git rev-parse HEAD) &&
328 q_to_nul >tag-NUL-header <<-EOF &&
331 tag contains-Q-in-header
332 tagger T A Gger <tagger@example.com> 1234567890 -0000
334 This is an invalid tag.
337 tag=$(git hash-object --literally -t tag -w --stdin <tag-NUL-header) &&
338 test_when_finished "remove_object $tag" &&
339 echo $tag >.git/refs/tags/wrong &&
340 test_when_finished "git update-ref -d refs/tags/wrong" &&
341 test_must_fail git fsck --tags 2>out &&
343 grep "error in tag $tag.*unterminated header: NUL at offset" out
346 test_expect_success 'cleaned up' '
347 git fsck >actual 2>&1 &&
348 test_must_be_empty actual
351 test_expect_success 'rev-list --verify-objects' '
352 git rev-list --verify-objects --all >/dev/null 2>out &&
353 test_must_be_empty out
356 test_expect_success 'rev-list --verify-objects with bad sha1' '
357 sha=$(echo blob | git hash-object -w --stdin) &&
358 old=$(echo $sha | sed "s+^..+&/+") &&
359 new=$(dirname $old)/ffffffffffffffffffffffffffffffffffffff &&
360 sha="$(dirname $new)$(basename $new)" &&
361 mv .git/objects/$old .git/objects/$new &&
362 test_when_finished "remove_object $sha" &&
363 git update-index --add --cacheinfo 100644 $sha foo &&
364 test_when_finished "git read-tree -u --reset HEAD" &&
365 tree=$(git write-tree) &&
366 test_when_finished "remove_object $tree" &&
367 cmt=$(echo bogus | git commit-tree $tree) &&
368 test_when_finished "remove_object $cmt" &&
369 git update-ref refs/heads/bogus $cmt &&
370 test_when_finished "git update-ref -d refs/heads/bogus" &&
372 test_might_fail git rev-list --verify-objects refs/heads/bogus >/dev/null 2>out &&
374 test_i18ngrep -q "error: sha1 mismatch 63ffffffffffffffffffffffffffffffffffffff" out
377 test_expect_success 'force fsck to ignore double author' '
378 git cat-file commit HEAD >basis &&
379 sed "s/^author .*/&,&/" <basis | tr , \\n >multiple-authors &&
380 new=$(git hash-object -t commit -w --stdin <multiple-authors) &&
381 test_when_finished "remove_object $new" &&
382 git update-ref refs/heads/bogus "$new" &&
383 test_when_finished "git update-ref -d refs/heads/bogus" &&
384 test_must_fail git fsck &&
385 git -c fsck.multipleAuthors=ignore fsck
389 _bz5="$_bz$_bz$_bz$_bz$_bz"
390 _bz20="$_bz5$_bz5$_bz5$_bz5"
392 test_expect_success 'fsck notices blob entry pointing to null sha1' '
393 (git init null-blob &&
395 sha=$(printf "100644 file$_bz$_bz20" |
396 git hash-object -w --stdin -t tree) &&
399 grep "warning.*null sha1" out
403 test_expect_success 'fsck notices submodule entry pointing to null sha1' '
404 (git init null-commit &&
406 sha=$(printf "160000 submodule$_bz$_bz20" |
407 git hash-object -w --stdin -t tree) &&
410 grep "warning.*null sha1" out
414 while read name path pretty; do
415 while read mode type; do
417 test_expect_success "fsck notices $pretty as $type" '
419 git init $name-$type &&
421 echo content >file &&
423 git commit -m base &&
424 blob=$(git rev-parse :file) &&
425 tree=$(git rev-parse HEAD^{tree}) &&
426 value=$(eval "echo \$$type") &&
427 printf "$mode $type %s\t%s" "$value" "$path" >bad &&
428 bad_tree=$(git mktree <bad) &&
431 grep "warning.*tree $bad_tree" out
442 dotgit-unicode .gI${u200c}T .gI{u200c}T
446 dot-backslash-case .\\\\.GIT\\\\foobar
447 dotgit-case-backslash .git\\\\foobar
450 test_expect_success 'fsck allows .Ňit' '
452 git init not-dotgit &&
454 echo content >file &&
456 git commit -m base &&
457 blob=$(git rev-parse :file) &&
458 printf "100644 blob $blob\t.\\305\\207it" >tree &&
459 tree=$(git mktree <tree) &&
461 test_line_count = 0 err
465 test_expect_success 'NUL in commit' '
466 rm -fr nul-in-commit &&
467 git init nul-in-commit &&
470 git commit --allow-empty -m "initial commitQNUL after message" &&
471 git cat-file commit HEAD >original &&
472 q_to_nul <original >munged &&
473 git hash-object -w -t commit --stdin <munged >name &&
474 git branch bad $(cat name) &&
476 test_must_fail git -c fsck.nulInCommit=error fsck 2>warn.1 &&
477 grep nulInCommit warn.1 &&
479 grep nulInCommit warn.2
483 # create a static test repo which is broken by omitting
484 # one particular object ($1, which is looked up via rev-parse
485 # in the new repository).
486 create_repo_missing () {
491 git commit -m one --allow-empty &&
493 echo content >subdir/file &&
494 git add subdir/file &&
496 unrelated=$(echo unrelated | git hash-object --stdin -w) &&
497 git tag -m foo tag $unrelated &&
498 sha1=$(git rev-parse --verify "$1") &&
499 path=$(echo $sha1 | sed 's|..|&/|') &&
500 rm .git/objects/$path
504 test_expect_success 'fsck notices missing blob' '
505 create_repo_missing HEAD:subdir/file &&
506 test_must_fail git -C missing fsck
509 test_expect_success 'fsck notices missing subtree' '
510 create_repo_missing HEAD:subdir &&
511 test_must_fail git -C missing fsck
514 test_expect_success 'fsck notices missing root tree' '
515 create_repo_missing HEAD^{tree} &&
516 test_must_fail git -C missing fsck
519 test_expect_success 'fsck notices missing parent' '
520 create_repo_missing HEAD^ &&
521 test_must_fail git -C missing fsck
524 test_expect_success 'fsck notices missing tagged object' '
525 create_repo_missing tag^{blob} &&
526 test_must_fail git -C missing fsck
529 test_expect_success 'fsck notices ref pointing to missing commit' '
530 create_repo_missing HEAD &&
531 test_must_fail git -C missing fsck
534 test_expect_success 'fsck notices ref pointing to missing tag' '
535 create_repo_missing tag &&
536 test_must_fail git -C missing fsck
539 test_expect_success 'fsck --connectivity-only' '
540 rm -rf connectivity-only &&
541 git init connectivity-only &&
543 cd connectivity-only &&
548 # Drop the index now; we want to be sure that we
549 # recursively notice the broken objects
550 # because they are reachable from refs, not because
551 # they are in the index.
554 # corrupt the blob, but in a way that we can still identify
555 # its type. That lets us see that --connectivity-only is
556 # not actually looking at the contents, but leaves it
557 # free to examine the type if it chooses.
558 empty=.git/objects/e6/9de29bb2d1d6434b8b29ae775ad8c2e48c5391 &&
559 blob=$(echo unrelated | git hash-object -w --stdin) &&
560 mv -f $(sha1_file $blob) $empty &&
562 test_must_fail git fsck --strict &&
563 git fsck --strict --connectivity-only &&
564 tree=$(git rev-parse HEAD:) &&
566 tree=.git/objects/${tree%$suffix}/$suffix &&
568 echo invalid >$tree &&
569 test_must_fail git fsck --strict --connectivity-only
573 test_expect_success 'fsck --connectivity-only with explicit head' '
574 rm -rf connectivity-only &&
575 git init connectivity-only &&
577 cd connectivity-only &&
580 tree=$(git rev-parse HEAD^{tree}) &&
581 remove_object $(git rev-parse HEAD:foo.t) &&
582 test_must_fail git fsck --connectivity-only $tree
586 test_expect_success 'fsck --name-objects' '
587 rm -rf name-objects &&
588 git init name-objects &&
591 test_commit julius caesar.t &&
592 test_commit augustus &&
593 test_commit caesar &&
594 remove_object $(git rev-parse julius:caesar.t) &&
595 test_must_fail git fsck --name-objects >out &&
596 tree=$(git rev-parse --verify julius:) &&
597 egrep "$tree \((refs/heads/master|HEAD)@\{[0-9]*\}:" out
601 test_expect_success 'alternate objects are correctly blamed' '
602 test_when_finished "rm -rf alt.git .git/objects/info/alternates" &&
603 git init --bare alt.git &&
604 echo "../../alt.git/objects" >.git/objects/info/alternates &&
605 mkdir alt.git/objects/12 &&
606 >alt.git/objects/12/34567890123456789012345678901234567890 &&
607 test_must_fail git fsck >out 2>&1 &&
611 test_expect_success 'fsck errors in packed objects' '
612 git cat-file commit HEAD >basis &&
613 sed "s/</one/" basis >one &&
614 sed "s/</foo/" basis >two &&
615 one=$(git hash-object -t commit -w one) &&
616 two=$(git hash-object -t commit -w two) &&
621 } | git pack-objects .git/objects/pack/pack
623 test_when_finished "rm -f .git/objects/pack/pack-$pack.*" &&
624 remove_object $one &&
625 remove_object $two &&
626 test_must_fail git fsck 2>out &&
627 grep "error in commit $one.* - bad name" out &&
628 grep "error in commit $two.* - bad name" out &&
632 test_expect_success 'fsck fails on corrupt packfile' '
633 hsh=$(git commit-tree -m mycommit HEAD^{tree}) &&
634 pack=$(echo $hsh | git pack-objects .git/objects/pack/pack) &&
636 # Corrupt the first byte of the first object. (It contains 3 type bits,
637 # at least one of which is not zero, so setting the first byte to 0 is
639 chmod a+w .git/objects/pack/pack-$pack.pack &&
640 printf '\0' | dd of=.git/objects/pack/pack-$pack.pack bs=1 conv=notrunc seek=12 &&
642 test_when_finished "rm -f .git/objects/pack/pack-$pack.*" &&
643 remove_object $hsh &&
644 test_must_fail git fsck 2>out &&
645 test_i18ngrep "checksum mismatch" out
648 test_expect_success 'fsck finds problems in duplicate loose objects' '
649 rm -rf broken-duplicate &&
650 git init broken-duplicate &&
652 cd broken-duplicate &&
653 test_commit duplicate &&
654 # no "-d" here, so we end up with duplicates
656 # now corrupt the loose copy
657 file=$(sha1_file "$(git rev-parse HEAD)") &&
659 echo broken >"$file" &&
660 test_must_fail git fsck
664 test_expect_success 'fsck detects trailing loose garbage (commit)' '
665 git cat-file commit HEAD >basis &&
666 echo bump-commit-sha1 >>basis &&
667 commit=$(git hash-object -w -t commit basis) &&
668 file=$(sha1_file $commit) &&
669 test_when_finished "remove_object $commit" &&
671 echo garbage >>"$file" &&
672 test_must_fail git fsck 2>out &&
673 test_i18ngrep "garbage.*$commit" out
676 test_expect_success 'fsck detects trailing loose garbage (blob)' '
677 blob=$(echo trailing | git hash-object -w --stdin) &&
678 file=$(sha1_file $blob) &&
679 test_when_finished "remove_object $blob" &&
681 echo garbage >>"$file" &&
682 test_must_fail git fsck 2>out &&
683 test_i18ngrep "garbage.*$blob" out
686 # for each of type, we have one version which is referenced by another object
687 # (and so while unreachable, not dangling), and another variant which really is
689 test_expect_success 'fsck notices dangling objects' '
693 blob=$(echo not-dangling | git hash-object -w --stdin) &&
694 dblob=$(echo dangling | git hash-object -w --stdin) &&
695 tree=$(printf "100644 blob %s\t%s\n" $blob one | git mktree) &&
696 dtree=$(printf "100644 blob %s\t%s\n" $blob two | git mktree) &&
697 commit=$(git commit-tree $tree) &&
698 dcommit=$(git commit-tree -p $commit $tree) &&
700 cat >expect <<-EOF &&
702 dangling commit $dcommit
707 # the output order is non-deterministic, as it comes from a hash
708 sort <actual >actual.sorted &&
709 test_cmp expect actual.sorted
713 test_expect_success 'fsck $name notices bogus $name' '
714 test_must_fail git fsck bogus &&
715 test_must_fail git fsck $ZERO_OID
718 test_expect_success 'bogus head does not fallback to all heads' '
719 # set up a case that will cause a reachability complaint
720 echo to-be-deleted >foo &&
722 blob=$(git rev-parse :foo) &&
723 test_when_finished "git rm --cached foo" &&
724 remove_object $blob &&
725 test_must_fail git fsck $ZERO_OID >out 2>&1 &&
729 # Corrupt the checksum on the index.
730 # Add 1 to the last byte in the SHA.
731 corrupt_index_checksum () {
734 open my $fh, "+<", ".git/index" or die "open: $!";
736 seek $fh, -1, SEEK_END or die "seek: $!";
737 read $fh, my $in_byte, 1 or die "read: $!";
739 $in_value = unpack("C", $in_byte);
740 $out_value = ($in_value + 1) & 255;
742 $out_byte = pack("C", $out_value);
744 seek $fh, -1, SEEK_END or die "seek: $!";
746 close $fh or die "close: $!";
750 # Corrupt the checksum on the index and then
751 # verify that only fsck notices.
752 test_expect_success 'detect corrupt index file in fsck' '
753 cp .git/index .git/index.backup &&
754 test_when_finished "mv .git/index.backup .git/index" &&
755 corrupt_index_checksum &&
756 test_must_fail git fsck --cache 2>errors &&
757 grep "bad index file" errors