git-fsck
(1)Verifies the connectivity and validity of the objects in the database
Options
11--unreachablePrint out objects that exist but that aren’t reachable from any of the reference nodes.
--rootReport root nodes.
--tagsReport tags.
--cacheConsider any object recorded in the index also as a head node for an unreachability trace.
--no-reflogsDo not consider commits that are referenced only by an entry in a reflog to be reachable. This option is meant only to search for commits that used to be in a ref, but now aren’t, but are still in that corresponding reflog.
--fullCheck not just objects in GIT_OBJECT_DIRECTORY ($GIT_DIR/objects), but also the ones found in alternate object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES or $GIT_DIR/objects/info/alternates, and in packed Git archives found in $GIT_DIR/objects/pack and corresponding pack subdirectories in alternate object pools. This is now default; you can turn it off with --no-full.
--connectivity-onlyCheck only the connectivity of reachable objects, making sure that any objects referenced by a reachable tag, commit, or tree are present. This speeds up the operation by avoiding reading blobs entirely (though it does still check that referenced blobs exist). This will detect corruption in commits and trees, but not do any semantic checks (e.g., for format errors). Corruption in blob objects will not be detected at all. Unreachable tags, commits, and trees will also be accessed to find the tips of dangling segments of history. Use --no-dangling if you don’t care about this output and want to
--strictEnable more strict checking, namely to catch a file mode recorded with g+w bit set, which was created by older versions of Git. Existing repositories, including the Linux kernel, Git itself, and sparse repository have old objects that trigger this check, but it is recommended to check new projects with this flag.
--verboseBe chatty.
--lost-foundWrite dangling objects into .git/lost-found/commit/ or .git/lost-found/other/, depending on type. If the object is a blob, the contents are written into the file, rather than its object name.
--name-objectsWhen displaying names of reachable objects, in addition to the SHA-1 also display a name that describes how they are reachable, compatible with git-rev-parse(1), e.g. HEAD@{1234567890}~25^2:src/.
DESCRIPTION
CONFIGURATION
Everything below this line in this section is selectively included from the git-config(1) documentation. The content is the same as what’s found there:
fsck.<msg-id>
Setting fsck.<msg-id> will be picked up by git-fsck(1), but to accept pushes of such data set receive.fsck.<msg-id> instead, or to clone or fetch it set fetch.fsck.<msg-id>.
The rest of the documentation discusses fsck.* for brevity, but the same applies for the corresponding receive.fsck.* and fetch.fsck.*. variables.
Unlike variables like color.ui and core.editor, the receive.fsck.<msg-id> and fetch.fsck.<msg-id> variables will not fall back on the fsck.<msg-id> configuration if they aren’t set. To uniformly configure the same fsck settings in different circumstances, all three of them must be set to the same values.
When fsck.<msg-id> is set, errors can be switched to warnings and vice versa by configuring the fsck.<msg-id> setting where the <msg-id> is the fsck message ID and the value is one of error, warn or ignore. For convenience, fsck prefixes the error/warning with the message ID, e.g. "missingEmail: invalid author/committer line - missing email" means that setting fsck.missingEmail = ignore will hide that issue.
In general, it is better to enumerate existing objects with problems with fsck.skipList, instead of listing the kind of breakages these problematic objects share to be ignored, as doing the latter will allow new instances of the same breakages go unnoticed.
Setting an unknown fsck.<msg-id> value will cause fsck to die, but doing the same for receive.fsck.<msg-id> and fetch.fsck.<msg-id> will only cause git to warn.
See the Fsck Messages section of git-fsck(1) for supported values of <msg-id>.
fsck.skipList
This feature is useful when an established project should be accepted despite early commits containing errors that can be safely ignored, such as invalid committer email addresses. Note: corrupt objects cannot be skipped with this setting.
Like fsck.<msg-id> this variable has corresponding receive.fsck.skipList and fetch.fsck.skipList variants.
Unlike variables like color.ui and core.editor the receive.fsck.skipList and fetch.fsck.skipList variables will not fall back on the fsck.skipList configuration if they aren’t set. To uniformly configure the same fsck settings in different circumstances, all three of them must be set to the same values.
Older versions of Git (before 2.20) documented that the object names list should be sorted. This was never a requirement; the object names could appear in any order, but when reading the list we tracked whether the list was sorted for the purposes of an internal binary search implementation, which could save itself some work with an already sorted list. Unless you had a humongous list there was no reason to go out of your way to pre-sort the list. After Git version 2.20 a hash implementation is used instead, so there’s now no reason to pre-sort the list.
DISCUSSION
git-fsck tests SHA-1 and general object sanity, and it does full tracking of the resulting reachability and everything else. It prints out any corruption it finds (missing or bad objects), and if you use the --unreachable flag it will also print out objects that exist but that aren’t reachable from any of the specified head nodes (or the default set, as mentioned above).
Any corrupt objects you will have to find in backups or other archives (i.e., you can just remove them and do an rsync with some other site in the hopes that somebody else has the object you have corrupted).
If core.commitGraph is true, the commit-graph file will also be inspected using git commit-graph verify. See git-commit-graph(1).
EXTRACTED DIAGNOSTICS
unreachable <type> <object>
missing <type> <object>
dangling <type> <object>
hash mismatch <object>
FSCK MESSAGES
The following lists the types of errors git fsck detects and what each error means, with their default severity. The severity of the error, other than those that are marked as "(FATAL)", can be tweaked by setting the corresponding fsck.<msg-id> configuration variable.
badDate
badDateOverflow
badEmail
badFilemode
badName
badObjectSha1
badParentSha1
badRefFiletype
badRefName
badTagName
badTimezone
badTree
badTreeSha1
badType
duplicateEntries
emptyName
extraHeaderEntry
fullPathname
gitattributesBlob
gitattributesLarge
gitattributesLineLength
gitattributesMissing
gitattributesSymlink
gitignoreSymlink
gitmodulesBlob
gitmodulesLarge
gitmodulesMissing
gitmodulesName
gitmodulesParse
gitmodulesLarge; (ERROR) .gitmodules blob is too large to parse.
gitmodulesPath
gitmodulesSymlink
gitmodulesUpdate
gitmodulesUrl
hasDot
hasDotdot
hasDotgit
largePathname
mailmapSymlink
missingAuthor
missingCommitter
missingEmail
missingNameBeforeEmail
missingObject
missingSpaceBeforeDate
missingSpaceBeforeEmail
missingTag
missingTagEntry
missingTaggerEntry
missingTree
missingType
missingTypeEntry
multipleAuthors
nulInCommit
nulInHeader
nullSha1
treeNotSorted
unknownType
unterminatedHeader
zeroPaddedDate
zeroPaddedFilemode