commit-graph: check order while reading fanout chunk

[git.git] / Documentation / config / core.txt

core.fileMode::
        Tells Git if the executable bit of files in the working tree
        is to be honored.
+
Some filesystems lose the executable bit when a file that is
marked as executable is checked out, or checks out a
non-executable file with executable bit on.
linkgit:git-clone[1] or linkgit:git-init[1] probe the filesystem
to see if it handles the executable bit correctly
and this variable is automatically set as necessary.
+
A repository, however, may be on a filesystem that handles
the filemode correctly, and this variable is set to 'true'
when created, but later may be made accessible from another
environment that loses the filemode (e.g. exporting ext4 via
CIFS mount, visiting a Cygwin created repository with
Git for Windows or Eclipse).
In such a case it may be necessary to set this variable to 'false'.
See linkgit:git-update-index[1].
+
The default is true (when core.filemode is not specified in the config file).

core.hideDotFiles::
        (Windows-only) If true, mark newly-created directories and files whose
        name starts with a dot as hidden.  If 'dotGitOnly', only the `.git/`
        directory is hidden, but no other files starting with a dot.  The
        default mode is 'dotGitOnly'.

core.ignoreCase::
        Internal variable which enables various workarounds to enable
        Git to work better on filesystems that are not case sensitive,
        like APFS, HFS+, FAT, NTFS, etc. For example, if a directory listing
        finds "makefile" when Git expects "Makefile", Git will assume
        it is really the same file, and continue to remember it as
        "Makefile".
+
The default is false, except linkgit:git-clone[1] or linkgit:git-init[1]
will probe and set core.ignoreCase true if appropriate when the repository
is created.
+
Git relies on the proper configuration of this variable for your operating
and file system. Modifying this value may result in unexpected behavior.

core.precomposeUnicode::
        This option is only used by Mac OS implementation of Git.
        When core.precomposeUnicode=true, Git reverts the unicode decomposition
        of filenames done by Mac OS. This is useful when sharing a repository
        between Mac OS and Linux or Windows.
        (Git for Windows 1.7.10 or higher is needed, or Git under cygwin 1.7).
        When false, file names are handled fully transparent by Git,
        which is backward compatible with older versions of Git.

core.protectHFS::
        If set to true, do not allow checkout of paths that would
        be considered equivalent to `.git` on an HFS+ filesystem.
        Defaults to `true` on Mac OS, and `false` elsewhere.

core.protectNTFS::
        If set to true, do not allow checkout of paths that would
        cause problems with the NTFS filesystem, e.g. conflict with
        8.3 "short" names.
        Defaults to `true` on Windows, and `false` elsewhere.

core.fsmonitor::
        If set to true, enable the built-in file system monitor
        daemon for this working directory (linkgit:git-fsmonitor{litdd}daemon[1]).
+
Like hook-based file system monitors, the built-in file system monitor
can speed up Git commands that need to refresh the Git index
(e.g. `git status`) in a working directory with many files.  The
built-in monitor eliminates the need to install and maintain an
external third-party tool.
+
The built-in file system monitor is currently available only on a
limited set of supported platforms.  Currently, this includes Windows
and MacOS.
+
        Otherwise, this variable contains the pathname of the "fsmonitor"
        hook command.
+
This hook command is used to identify all files that may have changed
since the requested date/time. This information is used to speed up
git by avoiding unnecessary scanning of files that have not changed.
+
See the "fsmonitor-watchman" section of linkgit:githooks[5].
+
Note that if you concurrently use multiple versions of Git, such
as one version on the command line and another version in an IDE
tool, that the definition of `core.fsmonitor` was extended to
allow boolean values in addition to hook pathnames.  Git versions
2.35.1 and prior will not understand the boolean values and will
consider the "true" or "false" values as hook pathnames to be
invoked.  Git versions 2.26 thru 2.35.1 default to hook protocol
V2 and will fall back to no fsmonitor (full scan).  Git versions
prior to 2.26 default to hook protocol V1 and will silently
assume there were no changes to report (no scan), so status
commands may report incomplete results.  For this reason, it is
best to upgrade all of your Git versions before using the built-in
file system monitor.

core.fsmonitorHookVersion::
        Sets the protocol version to be used when invoking the
        "fsmonitor" hook.
+
There are currently versions 1 and 2. When this is not set,
version 2 will be tried first and if it fails then version 1
will be tried. Version 1 uses a timestamp as input to determine
which files have changes since that time but some monitors
like Watchman have race conditions when used with a timestamp.
Version 2 uses an opaque string so that the monitor can return
something that can be used to determine what files have changed
without race conditions.

core.trustctime::
        If false, the ctime differences between the index and the
        working tree are ignored; useful when the inode change time
        is regularly modified by something outside Git (file system
        crawlers and some backup systems).
        See linkgit:git-update-index[1]. True by default.

core.splitIndex::
        If true, the split-index feature of the index will be used.
        See linkgit:git-update-index[1]. False by default.

core.untrackedCache::
        Determines what to do about the untracked cache feature of the
        index. It will be kept, if this variable is unset or set to
        `keep`. It will automatically be added if set to `true`. And
        it will automatically be removed, if set to `false`. Before
        setting it to `true`, you should check that mtime is working
        properly on your system.
        See linkgit:git-update-index[1]. `keep` by default, unless
        `feature.manyFiles` is enabled which sets this setting to
        `true` by default.

core.checkStat::
        When missing or is set to `default`, many fields in the stat
        structure are checked to detect if a file has been modified
        since Git looked at it.  When this configuration variable is
        set to `minimal`, sub-second part of mtime and ctime, the
        uid and gid of the owner of the file, the inode number (and
        the device number, if Git was compiled to use it), are
        excluded from the check among these fields, leaving only the
        whole-second part of mtime (and ctime, if `core.trustCtime`
        is set) and the filesize to be checked.
+
There are implementations of Git that do not leave usable values in
some fields (e.g. JGit); by excluding these fields from the
comparison, the `minimal` mode may help interoperability when the
same repository is used by these other systems at the same time.

core.quotePath::
        Commands that output paths (e.g. 'ls-files', 'diff'), will
        quote "unusual" characters in the pathname by enclosing the
        pathname in double-quotes and escaping those characters with
        backslashes in the same way C escapes control characters (e.g.
        `\t` for TAB, `\n` for LF, `\\` for backslash) or bytes with
        values larger than 0x80 (e.g. octal `\302\265` for "micro" in
        UTF-8).  If this variable is set to false, bytes higher than
        0x80 are not considered "unusual" any more. Double-quotes,
        backslash and control characters are always escaped regardless
        of the setting of this variable.  A simple space character is
        not considered "unusual".  Many commands can output pathnames
        completely verbatim using the `-z` option. The default value
        is true.

core.eol::
        Sets the line ending type to use in the working directory for
        files that are marked as text (either by having the `text`
        attribute set, or by having `text=auto` and Git auto-detecting
        the contents as text).
        Alternatives are 'lf', 'crlf' and 'native', which uses the platform's
        native line ending.  The default value is `native`.  See
        linkgit:gitattributes[5] for more information on end-of-line
        conversion. Note that this value is ignored if `core.autocrlf`
        is set to `true` or `input`.

core.safecrlf::
        If true, makes Git check if converting `CRLF` is reversible when
        end-of-line conversion is active.  Git will verify if a command
        modifies a file in the work tree either directly or indirectly.
        For example, committing a file followed by checking out the
        same file should yield the original file in the work tree.  If
        this is not the case for the current setting of
        `core.autocrlf`, Git will reject the file.  The variable can
        be set to "warn", in which case Git will only warn about an
        irreversible conversion but continue the operation.
+
CRLF conversion bears a slight chance of corrupting data.
When it is enabled, Git will convert CRLF to LF during commit and LF to
CRLF during checkout.  A file that contains a mixture of LF and
CRLF before the commit cannot be recreated by Git.  For text
files this is the right thing to do: it corrects line endings
such that we have only LF line endings in the repository.
But for binary files that are accidentally classified as text the
conversion can corrupt data.
+
If you recognize such corruption early you can easily fix it by
setting the conversion type explicitly in .gitattributes.  Right
after committing you still have the original file in your work
tree and this file is not yet corrupted.  You can explicitly tell
Git that this file is binary and Git will handle the file
appropriately.
+
Unfortunately, the desired effect of cleaning up text files with
mixed line endings and the undesired effect of corrupting binary
files cannot be distinguished.  In both cases CRLFs are removed
in an irreversible way.  For text files this is the right thing
to do because CRLFs are line endings, while for binary files
converting CRLFs corrupts data.
+
Note, this safety check does not mean that a checkout will generate a
file identical to the original file for a different setting of
`core.eol` and `core.autocrlf`, but only for the current one.  For
example, a text file with `LF` would be accepted with `core.eol=lf`
and could later be checked out with `core.eol=crlf`, in which case the
resulting file would contain `CRLF`, although the original file
contained `LF`.  However, in both work trees the line endings would be
consistent, that is either all `LF` or all `CRLF`, but never mixed.  A
file with mixed line endings would be reported by the `core.safecrlf`
mechanism.

core.autocrlf::
        Setting this variable to "true" is the same as setting
        the `text` attribute to "auto" on all files and core.eol to "crlf".
        Set to true if you want to have `CRLF` line endings in your
        working directory and the repository has LF line endings.
        This variable can be set to 'input',
        in which case no output conversion is performed.

core.checkRoundtripEncoding::
        A comma and/or whitespace separated list of encodings that Git
        performs UTF-8 round trip checks on if they are used in an
        `working-tree-encoding` attribute (see linkgit:gitattributes[5]).
        The default value is `SHIFT-JIS`.

core.symlinks::
        If false, symbolic links are checked out as small plain files that
        contain the link text. linkgit:git-update-index[1] and
        linkgit:git-add[1] will not change the recorded type to regular
        file. Useful on filesystems like FAT that do not support
        symbolic links.
+
The default is true, except linkgit:git-clone[1] or linkgit:git-init[1]
will probe and set core.symlinks false if appropriate when the repository
is created.

core.gitProxy::
        A "proxy command" to execute (as 'command host port') instead
        of establishing direct connection to the remote server when
        using the Git protocol for fetching. If the variable value is
        in the "COMMAND for DOMAIN" format, the command is applied only
        on hostnames ending with the specified domain string. This variable
        may be set multiple times and is matched in the given order;
        the first match wins.
+
Can be overridden by the `GIT_PROXY_COMMAND` environment variable
(which always applies universally, without the special "for"
handling).
+
The special string `none` can be used as the proxy command to
specify that no proxy be used for a given domain pattern.
This is useful for excluding servers inside a firewall from
proxy use, while defaulting to a common proxy for external domains.

core.sshCommand::
        If this variable is set, `git fetch` and `git push` will
        use the specified command instead of `ssh` when they need to
        connect to a remote system. The command is in the same form as
        the `GIT_SSH_COMMAND` environment variable and is overridden
        when the environment variable is set.

core.ignoreStat::
        If true, Git will avoid using lstat() calls to detect if files have
        changed by setting the "assume-unchanged" bit for those tracked files
        which it has updated identically in both the index and working tree.
+
When files are modified outside of Git, the user will need to stage
the modified files explicitly (e.g. see 'Examples' section in
linkgit:git-update-index[1]).
Git will not normally detect changes to those files.
+
This is useful on systems where lstat() calls are very slow, such as
CIFS/Microsoft Windows.
+
False by default.

core.preferSymlinkRefs::
        Instead of the default "symref" format for HEAD
        and other symbolic reference files, use symbolic links.
        This is sometimes needed to work with old scripts that
        expect HEAD to be a symbolic link.

core.alternateRefsCommand::
        When advertising tips of available history from an alternate, use the shell to
        execute the specified command instead of linkgit:git-for-each-ref[1]. The
        first argument is the absolute path of the alternate. Output must contain one
        hex object id per line (i.e., the same as produced by `git for-each-ref
        --format='%(objectname)'`).
+
Note that you cannot generally put `git for-each-ref` directly into the config
value, as it does not take a repository path as an argument (but you can wrap
the command above in a shell script).

core.alternateRefsPrefixes::
        When listing references from an alternate, list only references that begin
        with the given prefix. Prefixes match as if they were given as arguments to
        linkgit:git-for-each-ref[1]. To list multiple prefixes, separate them with
        whitespace. If `core.alternateRefsCommand` is set, setting
        `core.alternateRefsPrefixes` has no effect.

core.bare::
        If true this repository is assumed to be 'bare' and has no
        working directory associated with it.  If this is the case a
        number of commands that require a working directory will be
        disabled, such as linkgit:git-add[1] or linkgit:git-merge[1].
+
This setting is automatically guessed by linkgit:git-clone[1] or
linkgit:git-init[1] when the repository was created.  By default a
repository that ends in "/.git" is assumed to be not bare (bare =
false), while all other repositories are assumed to be bare (bare
= true).

core.worktree::
        Set the path to the root of the working tree.
        If `GIT_COMMON_DIR` environment variable is set, core.worktree
        is ignored and not used for determining the root of working tree.
        This can be overridden by the `GIT_WORK_TREE` environment
        variable and the `--work-tree` command-line option.
        The value can be an absolute path or relative to the path to
        the .git directory, which is either specified by --git-dir
        or GIT_DIR, or automatically discovered.
        If --git-dir or GIT_DIR is specified but none of
        --work-tree, GIT_WORK_TREE and core.worktree is specified,
        the current working directory is regarded as the top level
        of your working tree.
+
Note that this variable is honored even when set in a configuration
file in a ".git" subdirectory of a directory and its value differs
from the latter directory (e.g. "/path/to/.git/config" has
core.worktree set to "/different/path"), which is most likely a
misconfiguration.  Running Git commands in the "/path/to" directory will
still use "/different/path" as the root of the work tree and can cause
confusion unless you know what you are doing (e.g. you are creating a
read-only snapshot of the same index to a location different from the
repository's usual working tree).

core.logAllRefUpdates::
        Enable the reflog. Updates to a ref <ref> is logged to the file
        "`$GIT_DIR/logs/<ref>`", by appending the new and old
        SHA-1, the date/time and the reason of the update, but
        only when the file exists.  If this configuration
        variable is set to `true`, missing "`$GIT_DIR/logs/<ref>`"
        file is automatically created for branch heads (i.e. under
        `refs/heads/`), remote refs (i.e. under `refs/remotes/`),
        note refs (i.e. under `refs/notes/`), and the symbolic ref `HEAD`.
        If it is set to `always`, then a missing reflog is automatically
        created for any ref under `refs/`.
+
This information can be used to determine what commit
was the tip of a branch "2 days ago".
+
This value is true by default in a repository that has
a working directory associated with it, and false by
default in a bare repository.

core.repositoryFormatVersion::
        Internal variable identifying the repository format and layout
        version.

core.sharedRepository::
        When 'group' (or 'true'), the repository is made shareable between
        several users in a group (making sure all the files and objects are
        group-writable). When 'all' (or 'world' or 'everybody'), the
        repository will be readable by all users, additionally to being
        group-shareable. When 'umask' (or 'false'), Git will use permissions
        reported by umask(2). When '0xxx', where '0xxx' is an octal number,
        files in the repository will have this mode value. '0xxx' will override
        user's umask value (whereas the other options will only override
        requested parts of the user's umask value). Examples: '0660' will make
        the repo read/write-able for the owner and group, but inaccessible to
        others (equivalent to 'group' unless umask is e.g. '0022'). '0640' is a
        repository that is group-readable but not group-writable.
        See linkgit:git-init[1]. False by default.

core.warnAmbiguousRefs::
        If true, Git will warn you if the ref name you passed it is ambiguous
        and might match multiple refs in the repository. True by default.

core.compression::
        An integer -1..9, indicating a default compression level.
        -1 is the zlib default. 0 means no compression,
        and 1..9 are various speed/size tradeoffs, 9 being slowest.
        If set, this provides a default to other compression variables,
        such as `core.looseCompression` and `pack.compression`.

core.looseCompression::
        An integer -1..9, indicating the compression level for objects that
        are not in a pack file. -1 is the zlib default. 0 means no
        compression, and 1..9 are various speed/size tradeoffs, 9 being
        slowest.  If not set,  defaults to core.compression.  If that is
        not set,  defaults to 1 (best speed).

core.packedGitWindowSize::
        Number of bytes of a pack file to map into memory in a
        single mapping operation.  Larger window sizes may allow
        your system to process a smaller number of large pack files
        more quickly.  Smaller window sizes will negatively affect
        performance due to increased calls to the operating system's
        memory manager, but may improve performance when accessing
        a large number of large pack files.
+
Default is 1 MiB if NO_MMAP was set at compile time, otherwise 32
MiB on 32 bit platforms and 1 GiB on 64 bit platforms.  This should
be reasonable for all users/operating systems.  You probably do
not need to adjust this value.
+
Common unit suffixes of 'k', 'm', or 'g' are supported.

core.packedGitLimit::
        Maximum number of bytes to map simultaneously into memory
        from pack files.  If Git needs to access more than this many
        bytes at once to complete an operation it will unmap existing
        regions to reclaim virtual address space within the process.
+
Default is 256 MiB on 32 bit platforms and 32 TiB (effectively
unlimited) on 64 bit platforms.
This should be reasonable for all users/operating systems, except on
the largest projects.  You probably do not need to adjust this value.
+
Common unit suffixes of 'k', 'm', or 'g' are supported.

core.deltaBaseCacheLimit::
        Maximum number of bytes per thread to reserve for caching base objects
        that may be referenced by multiple deltified objects.  By storing the
        entire decompressed base objects in a cache Git is able
        to avoid unpacking and decompressing frequently used base
        objects multiple times.
+
Default is 96 MiB on all platforms.  This should be reasonable
for all users/operating systems, except on the largest projects.
You probably do not need to adjust this value.
+
Common unit suffixes of 'k', 'm', or 'g' are supported.

core.bigFileThreshold::
        The size of files considered "big", which as discussed below
        changes the behavior of numerous git commands, as well as how
        such files are stored within the repository. The default is
        512 MiB. Common unit suffixes of 'k', 'm', or 'g' are
        supported.
+
Files above the configured limit will be:
+
* Stored deflated in packfiles, without attempting delta compression.
+
The default limit is primarily set with this use-case in mind. With it,
most projects will have their source code and other text files delta
compressed, but not larger binary media files.
+
Storing large files without delta compression avoids excessive memory
usage, at the slight expense of increased disk usage.
+
* Will be treated as if they were labeled "binary" (see
  linkgit:gitattributes[5]). e.g. linkgit:git-log[1] and
  linkgit:git-diff[1] will not compute diffs for files above this limit.
+
* Will generally be streamed when written, which avoids excessive
memory usage, at the cost of some fixed overhead. Commands that make
use of this include linkgit:git-archive[1],
linkgit:git-fast-import[1], linkgit:git-index-pack[1],
linkgit:git-unpack-objects[1] and linkgit:git-fsck[1].

core.excludesFile::
        Specifies the pathname to the file that contains patterns to
        describe paths that are not meant to be tracked, in addition
        to `.gitignore` (per-directory) and `.git/info/exclude`.
        Defaults to `$XDG_CONFIG_HOME/git/ignore`.
        If `$XDG_CONFIG_HOME` is either not set or empty, `$HOME/.config/git/ignore`
        is used instead. See linkgit:gitignore[5].

core.askPass::
        Some commands (e.g. svn and http interfaces) that interactively
        ask for a password can be told to use an external program given
        via the value of this variable. Can be overridden by the `GIT_ASKPASS`
        environment variable. If not set, fall back to the value of the
        `SSH_ASKPASS` environment variable or, failing that, a simple password
        prompt. The external program shall be given a suitable prompt as
        command-line argument and write the password on its STDOUT.

core.attributesFile::
        In addition to `.gitattributes` (per-directory) and
        `.git/info/attributes`, Git looks into this file for attributes
        (see linkgit:gitattributes[5]). Path expansions are made the same
        way as for `core.excludesFile`. Its default value is
        `$XDG_CONFIG_HOME/git/attributes`. If `$XDG_CONFIG_HOME` is either not
        set or empty, `$HOME/.config/git/attributes` is used instead.

core.hooksPath::
        By default Git will look for your hooks in the
        `$GIT_DIR/hooks` directory. Set this to different path,
        e.g. `/etc/git/hooks`, and Git will try to find your hooks in
        that directory, e.g. `/etc/git/hooks/pre-receive` instead of
        in `$GIT_DIR/hooks/pre-receive`.
+
The path can be either absolute or relative. A relative path is
taken as relative to the directory where the hooks are run (see
the "DESCRIPTION" section of linkgit:githooks[5]).
+
This configuration variable is useful in cases where you'd like to
centrally configure your Git hooks instead of configuring them on a
per-repository basis, or as a more flexible and centralized
alternative to having an `init.templateDir` where you've changed
default hooks.

core.editor::
        Commands such as `commit` and `tag` that let you edit
        messages by launching an editor use the value of this
        variable when it is set, and the environment variable
        `GIT_EDITOR` is not set.  See linkgit:git-var[1].

core.commentChar::
        Commands such as `commit` and `tag` that let you edit
        messages consider a line that begins with this character
        commented, and removes them after the editor returns
        (default '#').
+
If set to "auto", `git-commit` would select a character that is not
the beginning character of any line in existing commit messages.

core.filesRefLockTimeout::
        The length of time, in milliseconds, to retry when trying to
        lock an individual reference. Value 0 means not to retry at
        all; -1 means to try indefinitely. Default is 100 (i.e.,
        retry for 100ms).

core.packedRefsTimeout::
        The length of time, in milliseconds, to retry when trying to
        lock the `packed-refs` file. Value 0 means not to retry at
        all; -1 means to try indefinitely. Default is 1000 (i.e.,
        retry for 1 second).

core.pager::
        Text viewer for use by Git commands (e.g., 'less').  The value
        is meant to be interpreted by the shell.  The order of preference
        is the `$GIT_PAGER` environment variable, then `core.pager`
        configuration, then `$PAGER`, and then the default chosen at
        compile time (usually 'less').
+
When the `LESS` environment variable is unset, Git sets it to `FRX`
(if `LESS` environment variable is set, Git does not change it at
all).  If you want to selectively override Git's default setting
for `LESS`, you can set `core.pager` to e.g. `less -S`.  This will
be passed to the shell by Git, which will translate the final
command to `LESS=FRX less -S`. The environment does not set the
`S` option but the command line does, instructing less to truncate
long lines. Similarly, setting `core.pager` to `less -+F` will
deactivate the `F` option specified by the environment from the
command-line, deactivating the "quit if one screen" behavior of
`less`.  One can specifically activate some flags for particular
commands: for example, setting `pager.blame` to `less -S` enables
line truncation only for `git blame`.
+
Likewise, when the `LV` environment variable is unset, Git sets it
to `-c`.  You can override this setting by exporting `LV` with
another value or setting `core.pager` to `lv +c`.

core.whitespace::
        A comma separated list of common whitespace problems to
        notice.  'git diff' will use `color.diff.whitespace` to
        highlight them, and 'git apply --whitespace=error' will
        consider them as errors.  You can prefix `-` to disable
        any of them (e.g. `-trailing-space`):
+
* `blank-at-eol` treats trailing whitespaces at the end of the line
  as an error (enabled by default).
* `space-before-tab` treats a space character that appears immediately
  before a tab character in the initial indent part of the line as an
  error (enabled by default).
* `indent-with-non-tab` treats a line that is indented with space
  characters instead of the equivalent tabs as an error (not enabled by
  default).
* `tab-in-indent` treats a tab character in the initial indent part of
  the line as an error (not enabled by default).
* `blank-at-eof` treats blank lines added at the end of file as an error
  (enabled by default).
* `trailing-space` is a short-hand to cover both `blank-at-eol` and
  `blank-at-eof`.
* `cr-at-eol` treats a carriage-return at the end of line as
  part of the line terminator, i.e. with it, `trailing-space`
  does not trigger if the character before such a carriage-return
  is not a whitespace (not enabled by default).
* `tabwidth=<n>` tells how many character positions a tab occupies; this
  is relevant for `indent-with-non-tab` and when Git fixes `tab-in-indent`
  errors. The default tab width is 8. Allowed values are 1 to 63.

core.fsync::
        A comma-separated list of components of the repository that
        should be hardened via the core.fsyncMethod when created or
        modified.  You can disable hardening of any component by
        prefixing it with a '-'.  Items that are not hardened may be
        lost in the event of an unclean system shutdown. Unless you
        have special requirements, it is recommended that you leave
        this option empty or pick one of `committed`, `added`,
        or `all`.
+
When this configuration is encountered, the set of components starts with
the platform default value, disabled components are removed, and additional
components are added. `none` resets the state so that the platform default
is ignored.
+
The empty string resets the fsync configuration to the platform
default. The default on most platforms is equivalent to
`core.fsync=committed,-loose-object`, which has good performance,
but risks losing recent work in the event of an unclean system shutdown.
+
* `none` clears the set of fsynced components.
* `loose-object` hardens objects added to the repo in loose-object form.
* `pack` hardens objects added to the repo in packfile form.
* `pack-metadata` hardens packfile bitmaps and indexes.
* `commit-graph` hardens the commit-graph file.
* `index` hardens the index when it is modified.
* `objects` is an aggregate option that is equivalent to
  `loose-object,pack`.
* `reference` hardens references modified in the repo.
* `derived-metadata` is an aggregate option that is equivalent to
  `pack-metadata,commit-graph`.
* `committed` is an aggregate option that is currently equivalent to
  `objects`. This mode sacrifices some performance to ensure that work
  that is committed to the repository with `git commit` or similar commands
  is hardened.
* `added` is an aggregate option that is currently equivalent to
  `committed,index`. This mode sacrifices additional performance to
  ensure that the results of commands like `git add` and similar operations
  are hardened.
* `all` is an aggregate option that syncs all individual components above.

core.fsyncMethod::
        A value indicating the strategy Git will use to harden repository data
        using fsync and related primitives.
+
* `fsync` uses the fsync() system call or platform equivalents.
* `writeout-only` issues pagecache writeback requests, but depending on the
  filesystem and storage hardware, data added to the repository may not be
  durable in the event of a system crash. This is the default mode on macOS.
* `batch` enables a mode that uses writeout-only flushes to stage multiple
  updates in the disk writeback cache and then does a single full fsync of
  a dummy file to trigger the disk cache flush at the end of the operation.
+
Currently `batch` mode only applies to loose-object files. Other repository
data is made durable as if `fsync` was specified. This mode is expected to
be as safe as `fsync` on macOS for repos stored on HFS+ or APFS filesystems
and on Windows for repos stored on NTFS or ReFS filesystems.

core.fsyncObjectFiles::
        This boolean will enable 'fsync()' when writing object files.
        This setting is deprecated. Use core.fsync instead.
+
This setting affects data added to the Git repository in loose-object
form. When set to true, Git will issue an fsync or similar system call
to flush caches so that loose-objects remain consistent in the face
of a unclean system shutdown.

core.preloadIndex::
        Enable parallel index preload for operations like 'git diff'
+
This can speed up operations like 'git diff' and 'git status' especially
on filesystems like NFS that have weak caching semantics and thus
relatively high IO latencies.  When enabled, Git will do the
index comparison to the filesystem data in parallel, allowing
overlapping IO's.  Defaults to true.

core.unsetenvvars::
        Windows-only: comma-separated list of environment variables'
        names that need to be unset before spawning any other process.
        Defaults to `PERL5LIB` to account for the fact that Git for
        Windows insists on using its own Perl interpreter.

core.restrictinheritedhandles::
        Windows-only: override whether spawned processes inherit only standard
        file handles (`stdin`, `stdout` and `stderr`) or all handles. Can be
        `auto`, `true` or `false`. Defaults to `auto`, which means `true` on
        Windows 7 and later, and `false` on older Windows versions.

core.createObject::
        You can set this to 'link', in which case a hardlink followed by
        a delete of the source are used to make sure that object creation
        will not overwrite existing objects.
+
On some file system/operating system combinations, this is unreliable.
Set this config setting to 'rename' there; However, This will remove the
check that makes sure that existing object files will not get overwritten.

core.notesRef::
        When showing commit messages, also show notes which are stored in
        the given ref.  The ref must be fully qualified.  If the given
        ref does not exist, it is not an error but means that no
        notes should be printed.
+
This setting defaults to "refs/notes/commits", and it can be overridden by
the `GIT_NOTES_REF` environment variable.  See linkgit:git-notes[1].

core.commitGraph::
        If true, then git will read the commit-graph file (if it exists)
        to parse the graph structure of commits. Defaults to true. See
        linkgit:git-commit-graph[1] for more information.

core.useReplaceRefs::
        If set to `false`, behave as if the `--no-replace-objects`
        option was given on the command line. See linkgit:git[1] and
        linkgit:git-replace[1] for more information.

core.multiPackIndex::
        Use the multi-pack-index file to track multiple packfiles using a
        single index. See linkgit:git-multi-pack-index[1] for more
        information. Defaults to true.

core.sparseCheckout::
        Enable "sparse checkout" feature. See linkgit:git-sparse-checkout[1]
        for more information.

core.sparseCheckoutCone::
        Enables the "cone mode" of the sparse checkout feature. When the
        sparse-checkout file contains a limited set of patterns, this
        mode provides significant performance advantages. The "non-cone
        mode" can be requested to allow specifying more flexible
        patterns by setting this variable to 'false'. See
        linkgit:git-sparse-checkout[1] for more information.

core.abbrev::
        Set the length object names are abbreviated to.  If
        unspecified or set to "auto", an appropriate value is
        computed based on the approximate number of packed objects
        in your repository, which hopefully is enough for
        abbreviated object names to stay unique for some time.
        If set to "no", no abbreviation is made and the object names
        are shown in their full length.
        The minimum length is 4.

core.maxTreeDepth::
        The maximum depth Git is willing to recurse while traversing a
        tree (e.g., "a/b/cde/f" has a depth of 4). This is a fail-safe
        to allow Git to abort cleanly, and should not generally need to
        be adjusted. The default is 4096.