merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

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+git-push(1)
+===========
+
+NAME
+----
+git-push - Update remote refs along with associated objects
+
+
+SYNOPSIS
+--------
+[verse]
+'git push' [--all | --mirror | --tags] [--follow-tags] [--atomic] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
+	   [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose]
+	   [-u | --set-upstream] [-o <string> | --push-option=<string>]
+	   [--[no-]signed|--signed=(true|false|if-asked)]
+	   [--force-with-lease[=<refname>[:<expect>]]]
+	   [--no-verify] [<repository> [<refspec>...]]
+
+DESCRIPTION
+-----------
+
+Updates remote refs using local refs, while sending objects
+necessary to complete the given refs.
+
+You can make interesting things happen to a repository
+every time you push into it, by setting up 'hooks' there.  See
+documentation for linkgit:git-receive-pack[1].
+
+When the command line does not specify where to push with the
+`<repository>` argument, `branch.*.remote` configuration for the
+current branch is consulted to determine where to push.  If the
+configuration is missing, it defaults to 'origin'.
+
+When the command line does not specify what to push with `<refspec>...`
+arguments or `--all`, `--mirror`, `--tags` options, the command finds
+the default `<refspec>` by consulting `remote.*.push` configuration,
+and if it is not found, honors `push.default` configuration to decide
+what to push (See linkgit:git-config[1] for the meaning of `push.default`).
+
+When neither the command-line nor the configuration specify what to
+push, the default behavior is used, which corresponds to the `simple`
+value for `push.default`: the current branch is pushed to the
+corresponding upstream branch, but as a safety measure, the push is
+aborted if the upstream branch does not have the same name as the
+local one.
+
+
+OPTIONS[[OPTIONS]]
+------------------
+<repository>::
+	The "remote" repository that is destination of a push
+	operation.  This parameter can be either a URL
+	(see the section <<URLS,GIT URLS>> below) or the name
+	of a remote (see the section <<REMOTES,REMOTES>> below).
+
+<refspec>...::
+	Specify what destination ref to update with what source object.
+	The format of a <refspec> parameter is an optional plus
+	`+`, followed by the source object <src>, followed
+	by a colon `:`, followed by the destination ref <dst>.
++
+The <src> is often the name of the branch you would want to push, but
+it can be any arbitrary "SHA-1 expression", such as `master~4` or
+`HEAD` (see linkgit:gitrevisions[7]).
++
+The <dst> tells which ref on the remote side is updated with this
+push. Arbitrary expressions cannot be used here, an actual ref must
+be named.
+If `git push [<repository>]` without any `<refspec>` argument is set to
+update some ref at the destination with `<src>` with
+`remote.<repository>.push` configuration variable, `:<dst>` part can
+be omitted--such a push will update a ref that `<src>` normally updates
+without any `<refspec>` on the command line.  Otherwise, missing
+`:<dst>` means to update the same ref as the `<src>`.
++
+If <dst> doesn't start with `refs/` (e.g. `refs/heads/master`) we will
+try to infer where in `refs/*` on the destination <repository> it
+belongs based on the type of <src> being pushed and whether <dst>
+is ambiguous.
++
+--
+* If <dst> unambiguously refers to a ref on the <repository> remote,
+  then push to that ref.
+
+* If <src> resolves to a ref starting with refs/heads/ or refs/tags/,
+  then prepend that to <dst>.
+
+* Other ambiguity resolutions might be added in the future, but for
+  now any other cases will error out with an error indicating what we
+  tried, and depending on the `advice.pushUnqualifiedRefname`
+  configuration (see linkgit:git-config[1]) suggest what refs/
+  namespace you may have wanted to push to.
+
+--
++
+The object referenced by <src> is used to update the <dst> reference
+on the remote side. Whether this is allowed depends on where in
+`refs/*` the <dst> reference lives as described in detail below, in
+those sections "update" means any modifications except deletes, which
+as noted after the next few sections are treated differently.
++
+The `refs/heads/*` namespace will only accept commit objects, and
+updates only if they can be fast-forwarded.
++
+The `refs/tags/*` namespace will accept any kind of object (as
+commits, trees and blobs can be tagged), and any updates to them will
+be rejected.
++
+It's possible to push any type of object to any namespace outside of
+`refs/{tags,heads}/*`. In the case of tags and commits, these will be
+treated as if they were the commits inside `refs/heads/*` for the
+purposes of whether the update is allowed.
++
+I.e. a fast-forward of commits and tags outside `refs/{tags,heads}/*`
+is allowed, even in cases where what's being fast-forwarded is not a
+commit, but a tag object which happens to point to a new commit which
+is a fast-forward of the commit the last tag (or commit) it's
+replacing. Replacing a tag with an entirely different tag is also
+allowed, if it points to the same commit, as well as pushing a peeled
+tag, i.e. pushing the commit that existing tag object points to, or a
+new tag object which an existing commit points to.
++
+Tree and blob objects outside of `refs/{tags,heads}/*` will be treated
+the same way as if they were inside `refs/tags/*`, any update of them
+will be rejected.
++
+All of the rules described above about what's not allowed as an update
+can be overridden by adding an the optional leading `+` to a refspec
+(or using `--force` command line option). The only exception to this
+is that no amount of forcing will make the `refs/heads/*` namespace
+accept a non-commit object. Hooks and configuration can also override
+or amend these rules, see e.g. `receive.denyNonFastForwards` in
+linkgit:git-config[1] and `pre-receive` and `update` in
+linkgit:githooks[5].
++
+Pushing an empty <src> allows you to delete the <dst> ref from the
+remote repository. Deletions are always accepted without a leading `+`
+in the refspec (or `--force`), except when forbidden by configuration
+or hooks. See `receive.denyDeletes` in linkgit:git-config[1] and
+`pre-receive` and `update` in linkgit:githooks[5].
++
+The special refspec `:` (or `+:` to allow non-fast-forward updates)
+directs Git to push "matching" branches: for every branch that exists on
+the local side, the remote side is updated if a branch of the same name
+already exists on the remote side.
++
+`tag <tag>` means the same as `refs/tags/<tag>:refs/tags/<tag>`.
+
+--all::
+	Push all branches (i.e. refs under `refs/heads/`); cannot be
+	used with other <refspec>.
+
+--prune::
+	Remove remote branches that don't have a local counterpart. For example
+	a remote branch `tmp` will be removed if a local branch with the same
+	name doesn't exist any more. This also respects refspecs, e.g.
+	`git push --prune remote refs/heads/*:refs/tmp/*` would
+	make sure that remote `refs/tmp/foo` will be removed if `refs/heads/foo`
+	doesn't exist.
+
+--mirror::
+	Instead of naming each ref to push, specifies that all
+	refs under `refs/` (which includes but is not
+	limited to `refs/heads/`, `refs/remotes/`, and `refs/tags/`)
+	be mirrored to the remote repository.  Newly created local
+	refs will be pushed to the remote end, locally updated refs
+	will be force updated on the remote end, and deleted refs
+	will be removed from the remote end.  This is the default
+	if the configuration option `remote.<remote>.mirror` is
+	set.
+
+-n::
+--dry-run::
+	Do everything except actually send the updates.
+
+--porcelain::
+	Produce machine-readable output.  The output status line for each ref
+	will be tab-separated and sent to stdout instead of stderr.  The full
+	symbolic names of the refs will be given.
+
+-d::
+--delete::
+	All listed refs are deleted from the remote repository. This is
+	the same as prefixing all refs with a colon.
+
+--tags::
+	All refs under `refs/tags` are pushed, in
+	addition to refspecs explicitly listed on the command
+	line.
+
+--follow-tags::
+	Push all the refs that would be pushed without this option,
+	and also push annotated tags in `refs/tags` that are missing
+	from the remote but are pointing at commit-ish that are
+	reachable from the refs being pushed.  This can also be specified
+	with configuration variable `push.followTags`.  For more
+	information, see `push.followTags` in linkgit:git-config[1].
+
+--[no-]signed::
+--signed=(true|false|if-asked)::
+	GPG-sign the push request to update refs on the receiving
+	side, to allow it to be checked by the hooks and/or be
+	logged.  If `false` or `--no-signed`, no signing will be
+	attempted.  If `true` or `--signed`, the push will fail if the
+	server does not support signed pushes.  If set to `if-asked`,
+	sign if and only if the server supports signed pushes.  The push
+	will also fail if the actual call to `gpg --sign` fails.  See
+	linkgit:git-receive-pack[1] for the details on the receiving end.
+
+--[no-]atomic::
+	Use an atomic transaction on the remote side if available.
+	Either all refs are updated, or on error, no refs are updated.
+	If the server does not support atomic pushes the push will fail.
+
+-o <option>::
+--push-option=<option>::
+	Transmit the given string to the server, which passes them to
+	the pre-receive as well as the post-receive hook. The given string
+	must not contain a NUL or LF character.
+	When multiple `--push-option=<option>` are given, they are
+	all sent to the other side in the order listed on the
+	command line.
+	When no `--push-option=<option>` is given from the command
+	line, the values of configuration variable `push.pushOption`
+	are used instead.
+
+--receive-pack=<git-receive-pack>::
+--exec=<git-receive-pack>::
+	Path to the 'git-receive-pack' program on the remote
+	end.  Sometimes useful when pushing to a remote
+	repository over ssh, and you do not have the program in
+	a directory on the default $PATH.
+
+--[no-]force-with-lease::
+--force-with-lease=<refname>::
+--force-with-lease=<refname>:<expect>::
+	Usually, "git push" refuses to update a remote ref that is
+	not an ancestor of the local ref used to overwrite it.
++
+This option overrides this restriction if the current value of the
+remote ref is the expected value.  "git push" fails otherwise.
++
+Imagine that you have to rebase what you have already published.
+You will have to bypass the "must fast-forward" rule in order to
+replace the history you originally published with the rebased history.
+If somebody else built on top of your original history while you are
+rebasing, the tip of the branch at the remote may advance with her
+commit, and blindly pushing with `--force` will lose her work.
++
+This option allows you to say that you expect the history you are
+updating is what you rebased and want to replace. If the remote ref
+still points at the commit you specified, you can be sure that no
+other people did anything to the ref. It is like taking a "lease" on
+the ref without explicitly locking it, and the remote ref is updated
+only if the "lease" is still valid.
++
+`--force-with-lease` alone, without specifying the details, will protect
+all remote refs that are going to be updated by requiring their
+current value to be the same as the remote-tracking branch we have
+for them.
++
+`--force-with-lease=<refname>`, without specifying the expected value, will
+protect the named ref (alone), if it is going to be updated, by
+requiring its current value to be the same as the remote-tracking
+branch we have for it.
++
+`--force-with-lease=<refname>:<expect>` will protect the named ref (alone),
+if it is going to be updated, by requiring its current value to be
+the same as the specified value `<expect>` (which is allowed to be
+different from the remote-tracking branch we have for the refname,
+or we do not even have to have such a remote-tracking branch when
+this form is used).  If `<expect>` is the empty string, then the named ref
+must not already exist.
++
+Note that all forms other than `--force-with-lease=<refname>:<expect>`
+that specifies the expected current value of the ref explicitly are
+still experimental and their semantics may change as we gain experience
+with this feature.
++
+"--no-force-with-lease" will cancel all the previous --force-with-lease on the
+command line.
++
+A general note on safety: supplying this option without an expected
+value, i.e. as `--force-with-lease` or `--force-with-lease=<refname>`
+interacts very badly with anything that implicitly runs `git fetch` on
+the remote to be pushed to in the background, e.g. `git fetch origin`
+on your repository in a cronjob.
++
+The protection it offers over `--force` is ensuring that subsequent
+changes your work wasn't based on aren't clobbered, but this is
+trivially defeated if some background process is updating refs in the
+background. We don't have anything except the remote tracking info to
+go by as a heuristic for refs you're expected to have seen & are
+willing to clobber.
++
+If your editor or some other system is running `git fetch` in the
+background for you a way to mitigate this is to simply set up another
+remote:
++
+	git remote add origin-push $(git config remote.origin.url)
+	git fetch origin-push
++
+Now when the background process runs `git fetch origin` the references
+on `origin-push` won't be updated, and thus commands like:
++
+	git push --force-with-lease origin-push
++
+Will fail unless you manually run `git fetch origin-push`. This method
+is of course entirely defeated by something that runs `git fetch
+--all`, in that case you'd need to either disable it or do something
+more tedious like:
++
+	git fetch              # update 'master' from remote
+	git tag base master    # mark our base point
+	git rebase -i master   # rewrite some commits
+	git push --force-with-lease=master:base master:master
++
+I.e. create a `base` tag for versions of the upstream code that you've
+seen and are willing to overwrite, then rewrite history, and finally
+force push changes to `master` if the remote version is still at
+`base`, regardless of what your local `remotes/origin/master` has been
+updated to in the background.
+
+-f::
+--force::
+	Usually, the command refuses to update a remote ref that is
+	not an ancestor of the local ref used to overwrite it.
+	Also, when `--force-with-lease` option is used, the command refuses
+	to update a remote ref whose current value does not match
+	what is expected.
++
+This flag disables these checks, and can cause the remote repository
+to lose commits; use it with care.
++
+Note that `--force` applies to all the refs that are pushed, hence
+using it with `push.default` set to `matching` or with multiple push
+destinations configured with `remote.*.push` may overwrite refs
+other than the current branch (including local refs that are
+strictly behind their remote counterpart).  To force a push to only
+one branch, use a `+` in front of the refspec to push (e.g `git push
+origin +master` to force a push to the `master` branch). See the
+`<refspec>...` section above for details.
+
+--repo=<repository>::
+	This option is equivalent to the <repository> argument. If both
+	are specified, the command-line argument takes precedence.
+
+-u::
+--set-upstream::
+	For every branch that is up to date or successfully pushed, add
+	upstream (tracking) reference, used by argument-less
+	linkgit:git-pull[1] and other commands. For more information,
+	see `branch.<name>.merge` in linkgit:git-config[1].
+
+--[no-]thin::
+	These options are passed to linkgit:git-send-pack[1]. A thin transfer
+	significantly reduces the amount of sent data when the sender and
+	receiver share many of the same objects in common. The default is
+	`--thin`.
+
+-q::
+--quiet::
+	Suppress all output, including the listing of updated refs,
+	unless an error occurs. Progress is not reported to the standard
+	error stream.
+
+-v::
+--verbose::
+	Run verbosely.
+
+--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.
+
+--no-recurse-submodules::
+--recurse-submodules=check|on-demand|only|no::
+	May be used to make sure all submodule commits used by the
+	revisions to be pushed are available on a remote-tracking branch.
+	If 'check' is used Git will verify that all submodule commits that
+	changed in the revisions to be pushed are available on at least one
+	remote of the submodule. If any commits are missing the push will
+	be aborted and exit with non-zero status. If 'on-demand' is used
+	all submodules that changed in the revisions to be pushed will be
+	pushed. If on-demand was not able to push all necessary revisions it will
+	also be aborted and exit with non-zero status. If 'only' is used all
+	submodules will be recursively pushed while the superproject is left
+	unpushed. A value of 'no' or using `--no-recurse-submodules` can be used
+	to override the push.recurseSubmodules configuration variable when no
+	submodule recursion is required.
+
+--[no-]verify::
+	Toggle the pre-push hook (see linkgit:githooks[5]).  The
+	default is --verify, giving the hook a chance to prevent the
+	push.  With --no-verify, the hook is bypassed completely.
+
+-4::
+--ipv4::
+	Use IPv4 addresses only, ignoring IPv6 addresses.
+
+-6::
+--ipv6::
+	Use IPv6 addresses only, ignoring IPv4 addresses.
+
+include::urls-remotes.txt[]
+
+OUTPUT
+------
+
+The output of "git push" depends on the transport method used; this
+section describes the output when pushing over the Git protocol (either
+locally or via ssh).
+
+The status of the push is output in tabular form, with each line
+representing the status of a single ref. Each line is of the form:
+
+-------------------------------
+ <flag> <summary> <from> -> <to> (<reason>)
+-------------------------------
+
+If --porcelain is used, then each line of the output is of the form:
+
+-------------------------------
+ <flag> \t <from>:<to> \t <summary> (<reason>)
+-------------------------------
+
+The status of up-to-date refs is shown only if --porcelain or --verbose
+option is used.
+
+flag::
+	A single character indicating the status of the ref:
+(space);; for a successfully pushed fast-forward;
+`+`;; for a successful forced update;
+`-`;; for a successfully deleted ref;
+`*`;; for a successfully pushed new ref;
+`!`;; for a ref that was rejected or failed to push; and
+`=`;; for a ref that was up to date and did not need pushing.
+
+summary::
+	For a successfully pushed ref, the summary shows the old and new
+	values of the ref in a form suitable for using as an argument to
+	`git log` (this is `<old>..<new>` in most cases, and
+	`<old>...<new>` for forced non-fast-forward updates).
++
+For a failed update, more details are given:
++
+--
+rejected::
+	Git did not try to send the ref at all, typically because it
+	is not a fast-forward and you did not force the update.
+
+remote rejected::
+	The remote end refused the update.  Usually caused by a hook
+	on the remote side, or because the remote repository has one
+	of the following safety options in effect:
+	`receive.denyCurrentBranch` (for pushes to the checked out
+	branch), `receive.denyNonFastForwards` (for forced
+	non-fast-forward updates), `receive.denyDeletes` or
+	`receive.denyDeleteCurrent`.  See linkgit:git-config[1].
+
+remote failure::
+	The remote end did not report the successful update of the ref,
+	perhaps because of a temporary error on the remote side, a
+	break in the network connection, or other transient error.
+--
+
+from::
+	The name of the local ref being pushed, minus its
+	`refs/<type>/` prefix. In the case of deletion, the
+	name of the local ref is omitted.
+
+to::
+	The name of the remote ref being updated, minus its
+	`refs/<type>/` prefix.
+
+reason::
+	A human-readable explanation. In the case of successfully pushed
+	refs, no explanation is needed. For a failed ref, the reason for
+	failure is described.
+
+NOTE ABOUT FAST-FORWARDS
+------------------------
+
+When an update changes a branch (or more in general, a ref) that used to
+point at commit A to point at another commit B, it is called a
+fast-forward update if and only if B is a descendant of A.
+
+In a fast-forward update from A to B, the set of commits that the original
+commit A built on top of is a subset of the commits the new commit B
+builds on top of.  Hence, it does not lose any history.
+
+In contrast, a non-fast-forward update will lose history.  For example,
+suppose you and somebody else started at the same commit X, and you built
+a history leading to commit B while the other person built a history
+leading to commit A.  The history looks like this:
+
+----------------
+
+      B
+     /
+ ---X---A
+
+----------------
+
+Further suppose that the other person already pushed changes leading to A
+back to the original repository from which you two obtained the original
+commit X.
+
+The push done by the other person updated the branch that used to point at
+commit X to point at commit A.  It is a fast-forward.
+
+But if you try to push, you will attempt to update the branch (that
+now points at A) with commit B.  This does _not_ fast-forward.  If you did
+so, the changes introduced by commit A will be lost, because everybody
+will now start building on top of B.
+
+The command by default does not allow an update that is not a fast-forward
+to prevent such loss of history.
+
+If you do not want to lose your work (history from X to B) or the work by
+the other person (history from X to A), you would need to first fetch the
+history from the repository, create a history that contains changes done
+by both parties, and push the result back.
+
+You can perform "git pull", resolve potential conflicts, and "git push"
+the result.  A "git pull" will create a merge commit C between commits A
+and B.
+
+----------------
+
+      B---C
+     /   /
+ ---X---A
+
+----------------
+
+Updating A with the resulting merge commit will fast-forward and your
+push will be accepted.
+
+Alternatively, you can rebase your change between X and B on top of A,
+with "git pull --rebase", and push the result back.  The rebase will
+create a new commit D that builds the change between X and B on top of
+A.
+
+----------------
+
+      B   D
+     /   /
+ ---X---A
+
+----------------
+
+Again, updating A with this commit will fast-forward and your push will be
+accepted.
+
+There is another common situation where you may encounter non-fast-forward
+rejection when you try to push, and it is possible even when you are
+pushing into a repository nobody else pushes into. After you push commit
+A yourself (in the first picture in this section), replace it with "git
+commit --amend" to produce commit B, and you try to push it out, because
+forgot that you have pushed A out already. In such a case, and only if
+you are certain that nobody in the meantime fetched your earlier commit A
+(and started building on top of it), you can run "git push --force" to
+overwrite it. In other words, "git push --force" is a method reserved for
+a case where you do mean to lose history.
+
+
+EXAMPLES
+--------
+
+`git push`::
+	Works like `git push <remote>`, where <remote> is the
+	current branch's remote (or `origin`, if no remote is
+	configured for the current branch).
+
+`git push origin`::
+	Without additional configuration, pushes the current branch to
+	the configured upstream (`remote.origin.merge` configuration
+	variable) if it has the same name as the current branch, and
+	errors out without pushing otherwise.
++
+The default behavior of this command when no <refspec> is given can be
+configured by setting the `push` option of the remote, or the `push.default`
+configuration variable.
++
+For example, to default to pushing only the current branch to `origin`
+use `git config remote.origin.push HEAD`.  Any valid <refspec> (like
+the ones in the examples below) can be configured as the default for
+`git push origin`.
+
+`git push origin :`::
+	Push "matching" branches to `origin`. See
+	<refspec> in the <<OPTIONS,OPTIONS>> section above for a
+	description of "matching" branches.
+
+`git push origin master`::
+	Find a ref that matches `master` in the source repository
+	(most likely, it would find `refs/heads/master`), and update
+	the same ref (e.g. `refs/heads/master`) in `origin` repository
+	with it.  If `master` did not exist remotely, it would be
+	created.
+
+`git push origin HEAD`::
+	A handy way to push the current branch to the same name on the
+	remote.
+
+`git push mothership master:satellite/master dev:satellite/dev`::
+	Use the source ref that matches `master` (e.g. `refs/heads/master`)
+	to update the ref that matches `satellite/master` (most probably
+	`refs/remotes/satellite/master`) in the `mothership` repository;
+	do the same for `dev` and `satellite/dev`.
++
+See the section describing `<refspec>...` above for a discussion of
+the matching semantics.
++
+This is to emulate `git fetch` run on the `mothership` using `git
+push` that is run in the opposite direction in order to integrate
+the work done on `satellite`, and is often necessary when you can
+only make connection in one way (i.e. satellite can ssh into
+mothership but mothership cannot initiate connection to satellite
+because the latter is behind a firewall or does not run sshd).
++
+After running this `git push` on the `satellite` machine, you would
+ssh into the `mothership` and run `git merge` there to complete the
+emulation of `git pull` that were run on `mothership` to pull changes
+made on `satellite`.
+
+`git push origin HEAD:master`::
+	Push the current branch to the remote ref matching `master` in the
+	`origin` repository. This form is convenient to push the current
+	branch without thinking about its local name.
+
+`git push origin master:refs/heads/experimental`::
+	Create the branch `experimental` in the `origin` repository
+	by copying the current `master` branch.  This form is only
+	needed to create a new branch or tag in the remote repository when
+	the local name and the remote name are different; otherwise,
+	the ref name on its own will work.
+
+`git push origin :experimental`::
+	Find a ref that matches `experimental` in the `origin` repository
+	(e.g. `refs/heads/experimental`), and delete it.
+
+`git push origin +dev:master`::
+	Update the origin repository's master branch with the dev branch,
+	allowing non-fast-forward updates.  *This can leave unreferenced
+	commits dangling in the origin repository.*  Consider the
+	following situation, where a fast-forward is not possible:
++
+----
+	    o---o---o---A---B  origin/master
+		     \
+		      X---Y---Z  dev
+----
++
+The above command would change the origin repository to
++
+----
+		      A---B  (unnamed branch)
+		     /
+	    o---o---o---X---Y---Z  master
+----
++
+Commits A and B would no longer belong to a branch with a symbolic name,
+and so would be unreachable.  As such, these commits would be removed by
+a `git gc` command on the origin repository.
+
+include::transfer-data-leaks.txt[]
+
+GIT
+---
+Part of the linkgit:git[1] suite