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] [<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 SHA1 references in .git/refs/*, and all reflogs (unless
--no-reflogs is given) as heads.
--unreachable
Print out objects that exist but that aren't readable from any of
the reference nodes.
--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.
--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.
It tests SHA1 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 readable from any of the specified head nodes.
So for example
git fsck --unreachable HEAD \
$(git for-each-ref --format="%(objectname)" refs/heads)
will do quite a lot of verification on the tree. There are a few extra
validity tests to be added (make sure that tree objects are sorted
properly etc), but on the whole if git fsck is happy, you do have a
valid tree.
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).
Of course, "valid tree" doesn't mean that it wasn't generated by some
evil person, and the end result might be crap. git is a revision
tracking system, not a quality assurance system ;)
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.
warning: git-fsck: tree <tree> has full pathnames in it
And it shouldn't...
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)
AUTHOR
Written by Linus Torvalds <torvalds@osdl.org[1]>
DOCUMENTATION
Documentation by David Greaves, Junio C Hamano and the git-list
<git@vger.kernel.org[2]>.
GIT
Part of the git(1) suite
NOTES
1. torvalds@osdl.org
mailto:torvalds@osdl.org
2. git@vger.kernel.org
mailto:git@vger.kernel.org