git-commit-vandalism/Documentation/fetch-options.txt

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--all::
Fetch all remotes.
-a::
--append::
Append ref names and object names of fetched refs to the
existing contents of `.git/FETCH_HEAD`. Without this
option old data in `.git/FETCH_HEAD` will be overwritten.
fetch: implement support for atomic reference updates When executing a fetch, then git will currently allocate one reference transaction per reference update and directly commit it. This means that fetches are non-atomic: even if some of the reference updates fail, others may still succeed and modify local references. This is fine in many scenarios, but this strategy has its downsides. - The view of remote references may be inconsistent and may show a bastardized state of the remote repository. - Batching together updates may improve performance in certain scenarios. While the impact probably isn't as pronounced with loose references, the upcoming reftable backend may benefit as it needs to write less files in case the update is batched. - The reference-update hook is currently being executed twice per updated reference. While this doesn't matter when there is no such hook, we have seen severe performance regressions when doing a git-fetch(1) with reference-transaction hook when the remote repository has hundreds of thousands of references. Similar to `git push --atomic`, this commit thus introduces atomic fetches. Instead of allocating one reference transaction per updated reference, it causes us to only allocate a single transaction and commit it as soon as all updates were received. If locking of any reference fails, then we abort the complete transaction and don't update any reference, which gives us an all-or-nothing fetch. Note that this may not completely fix the first of above downsides, as the consistent view also depends on the server-side. If the server doesn't have a consistent view of its own references during the reference negotiation phase, then the client would get the same inconsistent view the server has. This is a separate problem though and, if it actually exists, can be fixed at a later point. This commit also changes the way we write FETCH_HEAD in case `--atomic` is passed. Instead of writing changes as we go, we need to accumulate all changes first and only commit them at the end when we know that all reference updates succeeded. Ideally, we'd just do so via a temporary file so that we don't need to carry all updates in-memory. This isn't trivially doable though considering the `--append` mode, where we do not truncate the file but simply append to it. And given that we support concurrent processes appending to FETCH_HEAD at the same time without any loss of data, seeding the temporary file with current contents of FETCH_HEAD initially and then doing a rename wouldn't work either. So this commit implements the simple strategy of buffering all changes and appending them to the file on commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 13:27:52 +01:00
--atomic::
Use an atomic transaction to update local refs. Either all refs are
updated, or on error, no refs are updated.
--depth=<depth>::
Limit fetching to the specified number of commits from the tip of
each remote branch history. If fetching to a 'shallow' repository
created by `git clone` with `--depth=<depth>` option (see
linkgit:git-clone[1]), deepen or shorten the history to the specified
number of commits. Tags for the deepened commits are not fetched.
fetch, upload-pack: --deepen=N extends shallow boundary by N commits In git-fetch, --depth argument is always relative with the latest remote refs. This makes it a bit difficult to cover this use case, where the user wants to make the shallow history, say 3 levels deeper. It would work if remote refs have not moved yet, but nobody can guarantee that, especially when that use case is performed a couple months after the last clone or "git fetch --depth". Also, modifying shallow boundary using --depth does not work well with clones created by --since or --not. This patch fixes that. A new argument --deepen=<N> will add <N> more (*) parent commits to the current history regardless of where remote refs are. Have/Want negotiation is still respected. So if remote refs move, the server will send two chunks: one between "have" and "want" and another to extend shallow history. In theory, the client could send no "want"s in order to get the second chunk only. But the protocol does not allow that. Either you send no want lines, which means ls-remote; or you have to send at least one want line that carries deep-relative to the server.. The main work was done by Dongcan Jiang. I fixed it up here and there. And of course all the bugs belong to me. (*) We could even support --deepen=<N> where <N> is negative. In that case we can cut some history from the shallow clone. This operation (and --depth=<shorter depth>) does not require interaction with remote side (and more complicated to implement as a result). Helped-by: Duy Nguyen <pclouds@gmail.com> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Dongcan Jiang <dongcan.jiang@gmail.com> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-12 12:54:09 +02:00
--deepen=<depth>::
Similar to --depth, except it specifies the number of commits
from the current shallow boundary instead of from the tip of
each remote branch history.
--shallow-since=<date>::
Deepen or shorten the history of a shallow repository to
include all reachable commits after <date>.
--shallow-exclude=<revision>::
Deepen or shorten the history of a shallow repository to
exclude commits reachable from a specified remote branch or tag.
This option can be specified multiple times.
--unshallow::
If the source repository is complete, convert a shallow
repository to a complete one, removing all the limitations
imposed by shallow repositories.
+
If the source repository is shallow, fetch as much as possible so that
the current repository has the same history as the source repository.
--update-shallow::
By default when fetching from a shallow repository,
`git fetch` refuses refs that require updating
.git/shallow. This option updates .git/shallow and accept such
refs.
--negotiation-tip=<commit|glob>::
By default, Git will report, to the server, commits reachable
from all local refs to find common commits in an attempt to
reduce the size of the to-be-received packfile. If specified,
Git will only report commits reachable from the given tips.
This is useful to speed up fetches when the user knows which
local ref is likely to have commits in common with the
upstream ref being fetched.
+
This option may be specified more than once; if so, Git will report
commits reachable from any of the given commits.
+
The argument to this option may be a glob on ref names, a ref, or the (possibly
abbreviated) SHA-1 of a commit. Specifying a glob is equivalent to specifying
this option multiple times, one for each matching ref name.
+
See also the `fetch.negotiationAlgorithm` configuration variable
documented in linkgit:git-config[1].
--dry-run::
Show what would be done, without making any changes.
ifndef::git-pull[]
--[no-]write-fetch-head::
Write the list of remote refs fetched in the `FETCH_HEAD`
file directly under `$GIT_DIR`. This is the default.
Passing `--no-write-fetch-head` from the command line tells
Git not to write the file. Under `--dry-run` option, the
file is never written.
endif::git-pull[]
-f::
--force::
When 'git fetch' is used with `<src>:<dst>` refspec it may
refuse to update the local branch as discussed
ifdef::git-pull[]
in the `<refspec>` part of the linkgit:git-fetch[1]
documentation.
endif::git-pull[]
ifndef::git-pull[]
in the `<refspec>` part below.
endif::git-pull[]
This option overrides that check.
-k::
--keep::
Keep downloaded pack.
ifndef::git-pull[]
--multiple::
Allow several <repository> and <group> arguments to be
specified. No <refspec>s may be specified.
--[no-]auto-maintenance::
--[no-]auto-gc::
Run `git maintenance run --auto` at the end to perform automatic
repository maintenance if needed. (`--[no-]auto-gc` is a synonym.)
This is enabled by default.
--[no-]write-commit-graph::
Write a commit-graph after fetching. This overrides the config
setting `fetch.writeCommitGraph`.
endif::git-pull[]
-p::
--prune::
Before fetching, remove any remote-tracking references that no
fetch --prune: prune only based on explicit refspecs The old behavior of "fetch --prune" was to prune whatever was being fetched. In particular, "fetch --prune --tags" caused tags not only to be fetched, but also to be pruned. This is inappropriate because there is only one tags namespace that is shared among the local repository and all remotes. Therefore, if the user defines a local tag and then runs "git fetch --prune --tags", then the local tag is deleted. Moreover, "--prune" and "--tags" can also be configured via fetch.prune / remote.<name>.prune and remote.<name>.tagopt, making it even less obvious that an invocation of "git fetch" could result in tag lossage. Since the command "git remote update" invokes "git fetch", it had the same problem. The command "git remote prune", on the other hand, disregarded the setting of remote.<name>.tagopt, and so its behavior was inconsistent with that of the other commands. So the old behavior made it too easy to lose tags. To fix this problem, change "fetch --prune" to prune references based only on refspecs specified explicitly by the user, either on the command line or via remote.<name>.fetch. Thus, tags are no longer made subject to pruning by the --tags option or the remote.<name>.tagopt setting. However, tags *are* still subject to pruning if they are fetched as part of a refspec, and that is good. For example: * On the command line, git fetch --prune 'refs/tags/*:refs/tags/*' causes tags, and only tags, to be fetched and pruned, and is therefore a simple way for the user to get the equivalent of the old behavior of "--prune --tag". * For a remote that was configured with the "--mirror" option, the configuration is set to include [remote "name"] fetch = +refs/*:refs/* , which causes tags to be subject to pruning along with all other references. This is the behavior that will typically be desired for a mirror. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-30 06:33:00 +01:00
longer exist on the remote. Tags are not subject to pruning
if they are fetched only because of the default tag
auto-following or due to a --tags option. However, if tags
are fetched due to an explicit refspec (either on the command
line or in the remote configuration, for example if the remote
was cloned with the --mirror option), then they are also
fetch: add a --prune-tags option and fetch.pruneTags config Add a --prune-tags option to git-fetch, along with fetch.pruneTags config option and a -P shorthand (-p is --prune). This allows for doing any of: git fetch -p -P git fetch --prune --prune-tags git fetch -p -P origin git fetch --prune --prune-tags origin Or simply: git config fetch.prune true && git config fetch.pruneTags true && git fetch Instead of the much more verbose: git fetch --prune origin 'refs/tags/*:refs/tags/*' '+refs/heads/*:refs/remotes/origin/*' Before this feature it was painful to support the use-case of pulling from a repo which is having both its branches *and* tags deleted regularly, and have our local references to reflect upstream. At work we create deployment tags in the repo for each rollout, and there's *lots* of those, so they're archived within weeks for performance reasons. Without this change it's hard to centrally configure such repos in /etc/gitconfig (on servers that are only used for working with them). You need to set fetch.prune=true globally, and then for each repo: git -C {} config --replace-all remote.origin.fetch "refs/tags/*:refs/tags/*" "^\+*refs/tags/\*:refs/tags/\*$" Now I can simply set fetch.pruneTags=true in /etc/gitconfig as well, and users running "git pull" will automatically get the pruning semantics I want. Even though "git remote" has corresponding "prune" and "update --prune" subcommands I'm intentionally not adding a corresponding prune-tags or "update --prune --prune-tags" mode to that command. It's advertised (as noted in my recent "git remote doc: correct dangerous lies about what prune does") as only modifying remote tracking references, whereas any --prune-tags option is always going to modify what from the user's perspective is a local copy of the tag, since there's no such thing as a remote tracking tag. Ideally add_prune_tags_to_fetch_refspec() would be something that would use ALLOC_GROW() to grow the 'fetch` member of the 'remote' struct. Instead I'm realloc-ing remote->fetch and adding the tag_refspec to the end. The reason is that parse_{fetch,push}_refspec which allocate the refspec (ultimately remote->fetch) struct are called many places that don't have access to a 'remote' struct. It would be hard to change all their callsites to be amenable to carry around the bookkeeping variables required for dynamic allocation. All the other callers of the API first incrementally construct the string version of the refspec in remote->fetch_refspec via add_fetch_refspec(), before finally calling parse_fetch_refspec() via some variation of remote_get(). It's less of a pain to deal with the one special case that needs to modify already constructed refspecs than to chase down and change all the other callsites. The API I'm adding is intentionally not generalized because if we add more of these we'd probably want to re-visit how this is done. See my "Re: [BUG] git remote prune removes local tags, depending on fetch config" (87po6ahx87.fsf@evledraar.gmail.com; https://public-inbox.org/git/87po6ahx87.fsf@evledraar.gmail.com/) for more background info. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-09 21:32:15 +01:00
subject to pruning. Supplying `--prune-tags` is a shorthand for
providing the tag refspec.
ifndef::git-pull[]
fetch: add a --prune-tags option and fetch.pruneTags config Add a --prune-tags option to git-fetch, along with fetch.pruneTags config option and a -P shorthand (-p is --prune). This allows for doing any of: git fetch -p -P git fetch --prune --prune-tags git fetch -p -P origin git fetch --prune --prune-tags origin Or simply: git config fetch.prune true && git config fetch.pruneTags true && git fetch Instead of the much more verbose: git fetch --prune origin 'refs/tags/*:refs/tags/*' '+refs/heads/*:refs/remotes/origin/*' Before this feature it was painful to support the use-case of pulling from a repo which is having both its branches *and* tags deleted regularly, and have our local references to reflect upstream. At work we create deployment tags in the repo for each rollout, and there's *lots* of those, so they're archived within weeks for performance reasons. Without this change it's hard to centrally configure such repos in /etc/gitconfig (on servers that are only used for working with them). You need to set fetch.prune=true globally, and then for each repo: git -C {} config --replace-all remote.origin.fetch "refs/tags/*:refs/tags/*" "^\+*refs/tags/\*:refs/tags/\*$" Now I can simply set fetch.pruneTags=true in /etc/gitconfig as well, and users running "git pull" will automatically get the pruning semantics I want. Even though "git remote" has corresponding "prune" and "update --prune" subcommands I'm intentionally not adding a corresponding prune-tags or "update --prune --prune-tags" mode to that command. It's advertised (as noted in my recent "git remote doc: correct dangerous lies about what prune does") as only modifying remote tracking references, whereas any --prune-tags option is always going to modify what from the user's perspective is a local copy of the tag, since there's no such thing as a remote tracking tag. Ideally add_prune_tags_to_fetch_refspec() would be something that would use ALLOC_GROW() to grow the 'fetch` member of the 'remote' struct. Instead I'm realloc-ing remote->fetch and adding the tag_refspec to the end. The reason is that parse_{fetch,push}_refspec which allocate the refspec (ultimately remote->fetch) struct are called many places that don't have access to a 'remote' struct. It would be hard to change all their callsites to be amenable to carry around the bookkeeping variables required for dynamic allocation. All the other callers of the API first incrementally construct the string version of the refspec in remote->fetch_refspec via add_fetch_refspec(), before finally calling parse_fetch_refspec() via some variation of remote_get(). It's less of a pain to deal with the one special case that needs to modify already constructed refspecs than to chase down and change all the other callsites. The API I'm adding is intentionally not generalized because if we add more of these we'd probably want to re-visit how this is done. See my "Re: [BUG] git remote prune removes local tags, depending on fetch config" (87po6ahx87.fsf@evledraar.gmail.com; https://public-inbox.org/git/87po6ahx87.fsf@evledraar.gmail.com/) for more background info. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-09 21:32:15 +01:00
+
See the PRUNING section below for more details.
-P::
--prune-tags::
Before fetching, remove any local tags that no longer exist on
the remote if `--prune` is enabled. This option should be used
more carefully, unlike `--prune` it will remove any local
references (local tags) that have been created. This option is
a shorthand for providing the explicit tag refspec along with
`--prune`, see the discussion about that in its documentation.
+
See the PRUNING section below for more details.
endif::git-pull[]
ifndef::git-pull[]
-n::
endif::git-pull[]
--no-tags::
By default, tags that point at objects that are downloaded
from the remote repository are fetched and stored locally.
This option disables this automatic tag following. The default
behavior for a remote may be specified with the remote.<name>.tagOpt
setting. See linkgit:git-config[1].
--refmap=<refspec>::
When fetching refs listed on the command line, use the
specified refspec (can be given more than once) to map the
refs to remote-tracking branches, instead of the values of
`remote.*.fetch` configuration variables for the remote
fetch: document and test --refmap="" To prevent long blocking time during a 'git fetch' call, a user may want to set up a schedule for background 'git fetch' processes. However, these runs will update the refs/remotes branches due to the default refspec set in the config when Git adds a remote. Hence the user will not notice when remote refs are updated during their foreground fetches. In fact, they may _want_ those refs to stay put so they can work with the refs from their last foreground fetch call. This can be accomplished by overriding the configured refspec using '--refmap=' along with a custom refspec: git fetch --refmap='' <remote> +refs/heads/*:refs/hidden/<remote>/* to populate a custom ref space and download a pack of the new reachable objects. This kind of call allows a few things to happen: 1. We download a new pack if refs have updated. 2. Since the refs/hidden branches exist, GC will not remove the newly-downloaded data. 3. With fetch.writeCommitGraph enabled, the refs/hidden refs are used to update the commit-graph file. To avoid the refs/hidden directory from filling without bound, the --prune option can be included. When providing a refspec like this, the --prune option does not delete remote refs and instead only deletes refs in the target refspace. Update the documentation to clarify how '--refmap=""' works and create tests to guarantee this behavior remains in the future. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-21 02:38:12 +01:00
repository. Providing an empty `<refspec>` to the
`--refmap` option causes Git to ignore the configured
refspecs and rely entirely on the refspecs supplied as
command-line arguments. See section on "Configured Remote-tracking
Branches" for details.
-t::
--tags::
fetch --prune: prune only based on explicit refspecs The old behavior of "fetch --prune" was to prune whatever was being fetched. In particular, "fetch --prune --tags" caused tags not only to be fetched, but also to be pruned. This is inappropriate because there is only one tags namespace that is shared among the local repository and all remotes. Therefore, if the user defines a local tag and then runs "git fetch --prune --tags", then the local tag is deleted. Moreover, "--prune" and "--tags" can also be configured via fetch.prune / remote.<name>.prune and remote.<name>.tagopt, making it even less obvious that an invocation of "git fetch" could result in tag lossage. Since the command "git remote update" invokes "git fetch", it had the same problem. The command "git remote prune", on the other hand, disregarded the setting of remote.<name>.tagopt, and so its behavior was inconsistent with that of the other commands. So the old behavior made it too easy to lose tags. To fix this problem, change "fetch --prune" to prune references based only on refspecs specified explicitly by the user, either on the command line or via remote.<name>.fetch. Thus, tags are no longer made subject to pruning by the --tags option or the remote.<name>.tagopt setting. However, tags *are* still subject to pruning if they are fetched as part of a refspec, and that is good. For example: * On the command line, git fetch --prune 'refs/tags/*:refs/tags/*' causes tags, and only tags, to be fetched and pruned, and is therefore a simple way for the user to get the equivalent of the old behavior of "--prune --tag". * For a remote that was configured with the "--mirror" option, the configuration is set to include [remote "name"] fetch = +refs/*:refs/* , which causes tags to be subject to pruning along with all other references. This is the behavior that will typically be desired for a mirror. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-30 06:33:00 +01:00
Fetch all tags from the remote (i.e., fetch remote tags
`refs/tags/*` into local tags with the same name), in addition
to whatever else would otherwise be fetched. Using this
option alone does not subject tags to pruning, even if --prune
is used (though tags may be pruned anyway if they are also the
destination of an explicit refspec; see `--prune`).
ifndef::git-pull[]
--recurse-submodules[=yes|on-demand|no]::
This option controls if and under what conditions new commits of
populated submodules should be fetched too. It can be used as a
boolean option to completely disable recursion when set to 'no' or to
unconditionally recurse into all populated submodules when set to
'yes', which is the default when this option is used without any
value. Use 'on-demand' to only recurse into a populated submodule
when the superproject retrieves a commit that updates the submodule's
reference to a commit that isn't already in the local submodule
clone. By default, 'on-demand' is used, unless
`fetch.recurseSubmodules` is set (see linkgit:git-config[1]).
endif::git-pull[]
-j::
--jobs=<n>::
Number of parallel children to be used for all forms of fetching.
+
If the `--multiple` option was specified, the different remotes will be fetched
in parallel. If multiple submodules are fetched, they will be fetched in
parallel. To control them independently, use the config settings
`fetch.parallel` and `submodule.fetchJobs` (see linkgit:git-config[1]).
+
Typically, parallel recursive and multi-remote fetches will be faster. By
default fetches are performed sequentially, not in parallel.
ifndef::git-pull[]
--no-recurse-submodules::
Disable recursive fetching of submodules (this has the same effect as
using the `--recurse-submodules=no` option).
endif::git-pull[]
--set-upstream::
If the remote is fetched successfully, add upstream
(tracking) reference, used by argument-less
linkgit:git-pull[1] and other commands. For more information,
see `branch.<name>.merge` and `branch.<name>.remote` in
linkgit:git-config[1].
ifndef::git-pull[]
--submodule-prefix=<path>::
Prepend <path> to paths printed in informative messages
such as "Fetching submodule foo". This option is used
internally when recursing over submodules.
fetch/pull: recurse into submodules when necessary To be able to access all commits of populated submodules referenced by the superproject it is sufficient to only then let "git fetch" recurse into a submodule when the new commits fetched in the superproject record new commits for it. Having these commits present is extremely useful when using the "--submodule" option to "git diff" (which is what "git gui" and "gitk" do since 1.6.6), as all submodule commits needed for creating a descriptive output can be accessed. Also merging submodule commits (added in 1.7.3) depends on the submodule commits in question being present to work. Last but not least this enables disconnected operation when using submodules, as all commits necessary for a successful "git submodule update -N" will have been fetched automatically. So we choose this mode as the default for fetch and pull. Before a new or changed ref from upstream is updated in update_local_ref() "git rev-list <new-sha1> --not --branches --remotes" is used to determine all newly fetched commits. These are then walked and diffed against their parent(s) to see if a submodule has been changed. If that is the case, its path is stored to be fetched after the superproject fetch is completed. Using the "--recurse-submodules" or the "--no-recurse-submodules" option disables the examination of the fetched refs because the result will be ignored anyway. There is currently no infrastructure for storing deleted and new submodules in the .git directory of the superproject. That's why fetch and pull for now only fetch submodules that are already checked out and are not renamed. In t7403 the "--no-recurse-submodules" argument had to be added to "git pull" to avoid failure because of the moved upstream submodule repo. Thanks-to: Jonathan Nieder <jrnieder@gmail.com> Thanks-to: Heiko Voigt <hvoigt@hvoigt.net> Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-06 23:10:46 +01:00
--recurse-submodules-default=[yes|on-demand]::
This option is used internally to temporarily provide a
non-negative default value for the --recurse-submodules
option. All other methods of configuring fetch's submodule
recursion (such as settings in linkgit:gitmodules[5] and
linkgit:git-config[1]) override this option, as does
specifying --[no-]recurse-submodules directly.
-u::
--update-head-ok::
By default 'git fetch' refuses to update the head which
corresponds to the current branch. This flag disables the
check. This is purely for the internal use for 'git pull'
to communicate with 'git fetch', and unless you are
implementing your own Porcelain you are not supposed to
use it.
endif::git-pull[]
--upload-pack <upload-pack>::
When given, and the repository to fetch from is handled
by 'git fetch-pack', `--exec=<upload-pack>` is passed to
the command to specify non-default path for the command
run on the other end.
ifndef::git-pull[]
-q::
--quiet::
Pass --quiet to git-fetch-pack and silence any other internally
used git commands. Progress is not reported to the standard error
stream.
-v::
--verbose::
Be verbose.
endif::git-pull[]
--progress::
Progress status is reported on the standard error stream
by default when it is attached to a terminal, unless -q
is specified. This flag forces progress status even if the
standard error stream is not directed to a terminal.
-o <option>::
--server-option=<option>::
Transmit the given string to the server when communicating using
protocol version 2. The given string must not contain a NUL or LF
character. The server's handling of server options, including
unknown ones, is server-specific.
When multiple `--server-option=<option>` are given, they are all
sent to the other side in the order listed on the command line.
--show-forced-updates::
By default, git checks if a branch is force-updated during
fetch. This can be disabled through fetch.showForcedUpdates, but
the --show-forced-updates option guarantees this check occurs.
See linkgit:git-config[1].
--no-show-forced-updates::
By default, git checks if a branch is force-updated during
fetch. Pass --no-show-forced-updates or set fetch.showForcedUpdates
to false to skip this check for performance reasons. If used during
'git-pull' the --ff-only option will still check for forced updates
before attempting a fast-forward update. See linkgit:git-config[1].
-4::
--ipv4::
Use IPv4 addresses only, ignoring IPv6 addresses.
-6::
--ipv6::
Use IPv6 addresses only, ignoring IPv4 addresses.