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 the 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
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 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 trigger 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

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>
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.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
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 are
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 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>
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.

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
(ERROR) Invalid date format in an author/committer line.

badDateOverflow
(ERROR) Invalid date value in an author/committer line.

badEmail
(ERROR) Invalid email format in an author/committer line.

badFilemode
(INFO) A tree contains a bad filemode entry.

badName
(ERROR) An author/committer name is empty.

badObjectSha1
(ERROR) An object has a bad sha1.

badParentSha1
(ERROR) A commit object has a bad parent sha1.

badRefContent
(ERROR) A ref has bad content.

badRefFiletype
(ERROR) A ref has a bad file type.

badRefName
(ERROR) A ref has an invalid format.

badReferentName
(ERROR) The referent name of a symref is invalid.

badTagName
(INFO) A tag has an invalid format.

badTimezone
(ERROR) Found an invalid time zone in an author/committer line.

badTree
(ERROR) A tree cannot be parsed.

badTreeSha1
(ERROR) A tree has an invalid format.

badType
(ERROR) Found an invalid object type.

duplicateEntries
(ERROR) A tree contains duplicate file entries.

emptyName
(WARN) A path contains an empty name.

extraHeaderEntry
(IGNORE) Extra headers found after tagger.

fullPathname
(WARN) A path contains the full path starting with "/".

gitattributesBlob
(ERROR) A non-blob found at .gitattributes.

gitattributesLarge
(ERROR) The .gitattributes blob is too large.

gitattributesLineLength
(ERROR) The .gitattributes blob contains too long lines.

gitattributesMissing
(ERROR) Unable to read .gitattributes blob.

gitattributesSymlink
(INFO) .gitattributes is a symlink.

gitignoreSymlink
(INFO) .gitignore is a symlink.

gitmodulesBlob
(ERROR) A non-blob found at .gitmodules.

gitmodulesLarge
(ERROR) The .gitmodules file is too large to parse.

gitmodulesMissing
(ERROR) Unable to read .gitmodules blob.

gitmodulesName
(ERROR) A submodule name is invalid.

gitmodulesParse
(INFO) Could not parse .gitmodules blob.

gitmodulesLarge; (ERROR) .gitmodules blob is too large to parse.

gitmodulesPath
(ERROR) .gitmodules path is invalid.

gitmodulesSymlink
(ERROR) .gitmodules is a symlink.

gitmodulesUpdate
(ERROR) Found an invalid submodule update setting.

gitmodulesUrl
(ERROR) Found an invalid submodule url.

hasDot
(WARN) A tree contains an entry named ..

hasDotdot
(WARN) A tree contains an entry named ...

hasDotgit
(WARN) A tree contains an entry named .git.

largePathname
(WARN) A tree contains an entry with a very long path name. If
the value of fsck.largePathname contains a colon, that value is
used as the maximum allowable length (e.g., "warn:10" would
complain about any path component of 11 or more bytes). The
default value is 4096.

mailmapSymlink
(INFO) .mailmap is a symlink.

missingAuthor
(ERROR) Author is missing.

missingCommitter
(ERROR) Committer is missing.

missingEmail
(ERROR) Email is missing in an author/committer line.

missingNameBeforeEmail
(ERROR) Missing name before an email in an author/committer line.

missingObject
(ERROR) Missing object line in tag object.

missingSpaceBeforeDate
(ERROR) Missing space before date in an author/committer line.

missingSpaceBeforeEmail
(ERROR) Missing space before the email in an author/committer
line.

missingTag
(ERROR) Unexpected end after type line in a tag object.

missingTagEntry
(ERROR) Missing tag line in a tag object.

missingTaggerEntry
(INFO) Missing tagger line in a tag object.

missingTree
(ERROR) Missing tree line in a commit object.

missingType
(ERROR) Invalid type value on the type line in a tag object.

missingTypeEntry
(ERROR) Missing type line in a tag object.

multipleAuthors
(ERROR) Multiple author lines found in a commit.

nulInCommit
(WARN) Found a NUL byte in the commit object body.

nulInHeader
(FATAL) NUL byte exists in the object header.

nullSha1
(WARN) Tree contains entries pointing to a null sha1.

refMissingNewline
(INFO) A loose ref that does not end with newline(LF). As valid
implementations of Git never created such a loose ref file, it
may become an error in the future. Report to the
git@vger.kernel.org[1] mailing list if you see this error, as we
need to know what tools created such a file.

symlinkRef
(INFO) A symbolic link is used as a symref. Report to the
git@vger.kernel.org[1] mailing list if you see this error, as we
are assessing the feasibility of dropping the support to drop
creating symbolic links as symrefs.

symrefTargetIsNotARef
(INFO) The target of a symbolic reference points neither to a
root reference nor to a reference starting with "refs/". Although
we allow create a symref pointing to the referent which is
outside the "ref" by using git symbolic-ref, we may tighten the
rule in the future. Report to the git@vger.kernel.org[1] mailing
list if you see this error, as we need to know what tools created
such a file.

trailingRefContent
(INFO) A loose ref has trailing content. As valid implementations
of Git never created such a loose ref file, it may become an
error in the future. Report to the git@vger.kernel.org[1] mailing
list if you see this error, as we need to know what tools created
such a file.

treeNotSorted
(ERROR) A tree is not properly sorted.

unknownType
(ERROR) Found an unknown object type.

unterminatedHeader
(FATAL) Missing end-of-line in the object header.

zeroPaddedDate
(ERROR) Found a zero padded date in an author/committer line.

zeroPaddedFilemode
(WARN) Found a zero padded filemode in a tree.

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

NOTES

1. git@vger.kernel.org
mailto:git@vger.kernel.org

Git 2.48.1 2025-01-13 GIT-FSCK(1)