git/Documentation/config/fsck.txt

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.
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Setting `fsck.<msg-id>` will be picked up by linkgit: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>`.
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The rest of the documentation discusses `fsck.*` for brevity, but the
same applies for the corresponding `receive.fsck.*` and
`fetch.<msg-id>.*`. variables.
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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.
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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.
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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.
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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.
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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.
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Like `fsck.<msg-id>` this variable has corresponding
`receive.fsck.skipList` and `fetch.fsck.skipList` variants.
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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.
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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.