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t4034: abstract away SHA-1-specific constants
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1 git-fsck(1)
2 ===========
3
4 NAME
5 ----
6 git-fsck - Verifies the connectivity and validity of the objects in the database
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git fsck' [--tags] [--root] [--unreachable] [--cache] [--no-reflogs]
13 [--[no-]full] [--strict] [--verbose] [--lost-found]
14 [--[no-]dangling] [--[no-]progress] [--connectivity-only]
15 [--[no-]name-objects] [<object>*]
16
17 DESCRIPTION
18 -----------
19 Verifies the connectivity and validity of the objects in the database.
20
21 OPTIONS
22 -------
23 <object>::
24 An object to treat as the head of an unreachability trace.
25 +
26 If no objects are given, 'git fsck' defaults to using the
27 index file, all SHA-1 references in `refs` namespace, and all reflogs
28 (unless --no-reflogs is given) as heads.
29
30 --unreachable::
31 Print out objects that exist but that aren't reachable from any
32 of the reference nodes.
33
34 --[no-]dangling::
35 Print objects that exist but that are never 'directly' used (default).
36 `--no-dangling` can be used to omit this information from the output.
37
38 --root::
39 Report root nodes.
40
41 --tags::
42 Report tags.
43
44 --cache::
45 Consider any object recorded in the index also as a head node for
46 an unreachability trace.
47
48 --no-reflogs::
49 Do not consider commits that are referenced only by an
50 entry in a reflog to be reachable. This option is meant
51 only to search for commits that used to be in a ref, but
52 now aren't, but are still in that corresponding reflog.
53
54 --full::
55 Check not just objects in GIT_OBJECT_DIRECTORY
56 ($GIT_DIR/objects), but also the ones found in alternate
57 object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES
58 or $GIT_DIR/objects/info/alternates,
59 and in packed Git archives found in $GIT_DIR/objects/pack
60 and corresponding pack subdirectories in alternate
61 object pools. This is now default; you can turn it off
62 with --no-full.
63
64 --connectivity-only::
65 Check only the connectivity of reachable objects, making sure
66 that any objects referenced by a reachable tag, commit, or tree
67 is present. This speeds up the operation by avoiding reading
68 blobs entirely (though it does still check that referenced blobs
69 exist). This will detect corruption in commits and trees, but
70 not do any semantic checks (e.g., for format errors). Corruption
71 in blob objects will not be detected at all.
72 +
73 Unreachable tags, commits, and trees will also be accessed to find the
74 tips of dangling segments of history. Use `--no-dangling` if you don't
75 care about this output and want to speed it up further.
76
77 --strict::
78 Enable more strict checking, namely to catch a file mode
79 recorded with g+w bit set, which was created by older
80 versions of Git. Existing repositories, including the
81 Linux kernel, Git itself, and sparse repository have old
82 objects that triggers this check, but it is recommended
83 to check new projects with this flag.
84
85 --verbose::
86 Be chatty.
87
88 --lost-found::
89 Write dangling objects into .git/lost-found/commit/ or
90 .git/lost-found/other/, depending on type. If the object is
91 a blob, the contents are written into the file, rather than
92 its object name.
93
94 --name-objects::
95 When displaying names of reachable objects, in addition to the
96 SHA-1 also display a name that describes *how* they are reachable,
97 compatible with linkgit:git-rev-parse[1], e.g.
98 `HEAD@{1234567890}~25^2:src/`.
99
100 --[no-]progress::
101 Progress status is reported on the standard error stream by
102 default when it is attached to a terminal, unless
103 --no-progress or --verbose is specified. --progress forces
104 progress status even if the standard error stream is not
105 directed to a terminal.
106
107 CONFIGURATION
108 -------------
109
110 include::config/fsck.txt[]
111
112 DISCUSSION
113 ----------
114
115 git-fsck tests SHA-1 and general object sanity, and it does full tracking
116 of the resulting reachability and everything else. It prints out any
117 corruption it finds (missing or bad objects), and if you use the
118 `--unreachable` flag it will also print out objects that exist but that
119 aren't reachable from any of the specified head nodes (or the default
120 set, as mentioned above).
121
122 Any corrupt objects you will have to find in backups or other archives
123 (i.e., you can just remove them and do an 'rsync' with some other site in
124 the hopes that somebody else has the object you have corrupted).
125
126 If core.commitGraph is true, the commit-graph file will also be inspected
127 using 'git commit-graph verify'. See linkgit:git-commit-graph[1].
128
129 Extracted Diagnostics
130 ---------------------
131
132 expect dangling commits - potential heads - due to lack of head information::
133 You haven't specified any nodes as heads so it won't be
134 possible to differentiate between un-parented commits and
135 root nodes.
136
137 missing sha1 directory '<dir>'::
138 The directory holding the sha1 objects is missing.
139
140 unreachable <type> <object>::
141 The <type> object <object>, isn't actually referred to directly
142 or indirectly in any of the trees or commits seen. This can
143 mean that there's another root node that you're not specifying
144 or that the tree is corrupt. If you haven't missed a root node
145 then you might as well delete unreachable nodes since they
146 can't be used.
147
148 missing <type> <object>::
149 The <type> object <object>, is referred to but isn't present in
150 the database.
151
152 dangling <type> <object>::
153 The <type> object <object>, is present in the database but never
154 'directly' used. A dangling commit could be a root node.
155
156 hash mismatch <object>::
157 The database has an object whose hash doesn't match the
158 object database value.
159 This indicates a serious data integrity problem.
160
161 Environment Variables
162 ---------------------
163
164 GIT_OBJECT_DIRECTORY::
165 used to specify the object database root (usually $GIT_DIR/objects)
166
167 GIT_INDEX_FILE::
168 used to specify the index file of the index
169
170 GIT_ALTERNATE_OBJECT_DIRECTORIES::
171 used to specify additional object database roots (usually unset)
172
173 GIT
174 ---
175 Part of the linkgit:git[1] suite