git-fsck - Online in the Cloud

PROGRAM:

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] [<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 tags, commits and tree objects. By avoiding to unpack
blobs, this speeds up the operation, at the expense of missing corrupt objects or
other problematic issues.

--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.

--[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.

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).

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.

sha1 mismatch <object>
The database has an object who’s sha1 doesn’t match the 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

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