git-fsck

GIT-FSCK(1)                       Git Manual                       GIT-FSCK(1)

NAME
       git-fsck - Verifies the connectivity and validity of the objects in the
       database

SYNOPSIS
       git fsck [--tags] [--root] [--unreachable] [--cache] [--no-reflogs]
                [--[no-]full] [--strict] [--verbose] [--lost-found]
                [--[no-]dangling] [--[no-]progress] [--connectivity-only]
                [--[no-]name-objects] [<object>*]

DESCRIPTION
       Verifies the connectivity and validity of the objects in the database.

OPTIONS
       <object>
           An object to treat as the head of an unreachability trace.

           If no objects are given, git fsck defaults to using the index file,
           all SHA-1 references in refs namespace, and all reflogs (unless
           --no-reflogs is given) as heads.

       --unreachable
           Print out objects that exist but that aren't reachable from any of
           the reference nodes.

       --[no-]dangling
           Print objects that exist but that are never directly used
           (default).  --no-dangling can be used to omit this information from
           the output.

       --root
           Report root nodes.

       --tags
           Report tags.

       --cache
           Consider any object recorded in the index also as a head node for
           an unreachability trace.

       --no-reflogs
           Do 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.

       --full
           Check 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-only
           Check only the connectivity of reachable objects, making sure that
           any objects referenced by a reachable tag, commit, or tree is
           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 speed it up further.

       --strict
           Enable 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 triggers this check, but it
           is recommended to check new projects with this flag.

       --verbose
           Be chatty.

       --lost-found
           Write 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-objects
           When 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/.

       --[no-]progress
           Progress status is reported on the standard error stream by default
           when it is attached to a terminal, unless --no-progress or
           --verbose is specified. --progress forces progress status even if
           the standard error stream is not directed to a terminal.

CONFIGURATION
       fsck.<msg-id>
           During fsck git may find issues with legacy data which wouldn't be
           generated by current versions of git, and which wouldn't be sent
           over the wire if transfer.fsckObjects was set. This feature is
           intended to support working with legacy repositories containing
           such data.

           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.<msg-id>.*. 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 they must all 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.

       fsck.skipList
           The path to a list of object names (i.e. one unabbreviated SHA-1
           per line) that are known to be broken in a non-fatal way and should
           be ignored. On versions of Git 2.20 and later comments (#), empty
           lines, and any leading and trailing whitespace is ignored.
           Everything but a SHA-1 per line will error out on older versions.

           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 they must all 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
       expect dangling commits - potential heads - due to lack of head
       information
           You haven't specified any nodes as heads so it won't be possible to
           differentiate between un-parented commits and root nodes.

       missing sha1 directory <dir>
           The directory holding the sha1 objects is missing.

       unreachable <type> <object>
           The <type> object <object>, isn't actually referred to directly or
           indirectly in any of the trees or commits seen. This can mean that
           there's another root node that you're not specifying or that the
           tree is corrupt. If you haven't missed a root node then you might
           as well delete unreachable nodes since they can't be used.

       missing <type> <object>
           The <type> object <object>, is referred to but isn't present in the
           database.

       dangling <type> <object>
           The <type> object <object>, is present in the database but never
           directly used. A dangling commit could be a root node.

       hash mismatch <object>
           The database has an object whose hash doesn't match the object
           database value. This indicates a serious data integrity problem.

ENVIRONMENT VARIABLES
       GIT_OBJECT_DIRECTORY
           used to specify the object database root (usually $GIT_DIR/objects)

       GIT_INDEX_FILE
           used to specify the index file of the index

       GIT_ALTERNATE_OBJECT_DIRECTORIES
           used to specify additional object database roots (usually unset)

GIT
       Part of the git(1) suite

Git 2.25.1                        04/26/2023                       GIT-FSCK(1)