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Plaintext
1213 строки
42 KiB
Plaintext
git-rebase(1)
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=============
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NAME
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----
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git-rebase - Reapply commits on top of another base tip
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SYNOPSIS
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--------
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[verse]
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'git rebase' [-i | --interactive] [<options>] [--exec <cmd>]
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[--onto <newbase> | --keep-base] [<upstream> [<branch>]]
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'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
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--root [<branch>]
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'git rebase' (--continue | --skip | --abort | --quit | --edit-todo | --show-current-patch)
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DESCRIPTION
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-----------
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If <branch> is specified, 'git rebase' will perform an automatic
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`git switch <branch>` before doing anything else. Otherwise
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it remains on the current branch.
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If <upstream> is not specified, the upstream configured in
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branch.<name>.remote and branch.<name>.merge options will be used (see
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linkgit:git-config[1] for details) and the `--fork-point` option is
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assumed. If you are currently not on any branch or if the current
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branch does not have a configured upstream, the rebase will abort.
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All changes made by commits in the current branch but that are not
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in <upstream> are saved to a temporary area. This is the same set
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of commits that would be shown by `git log <upstream>..HEAD`; or by
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`git log 'fork_point'..HEAD`, if `--fork-point` is active (see the
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description on `--fork-point` below); or by `git log HEAD`, if the
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`--root` option is specified.
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The current branch is reset to <upstream>, or <newbase> if the
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--onto option was supplied. This has the exact same effect as
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`git reset --hard <upstream>` (or <newbase>). ORIG_HEAD is set
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to point at the tip of the branch before the reset.
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The commits that were previously saved into the temporary area are
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then reapplied to the current branch, one by one, in order. Note that
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any commits in HEAD which introduce the same textual changes as a commit
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in HEAD..<upstream> are omitted (i.e., a patch already accepted upstream
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with a different commit message or timestamp will be skipped).
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It is possible that a merge failure will prevent this process from being
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completely automatic. You will have to resolve any such merge failure
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and run `git rebase --continue`. Another option is to bypass the commit
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that caused the merge failure with `git rebase --skip`. To check out the
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original <branch> and remove the .git/rebase-apply working files, use the
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command `git rebase --abort` instead.
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Assume the following history exists and the current branch is "topic":
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------------
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A---B---C topic
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/
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D---E---F---G master
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------------
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From this point, the result of either of the following commands:
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git rebase master
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git rebase master topic
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would be:
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------------
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A'--B'--C' topic
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/
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D---E---F---G master
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------------
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*NOTE:* The latter form is just a short-hand of `git checkout topic`
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followed by `git rebase master`. When rebase exits `topic` will
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remain the checked-out branch.
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If the upstream branch already contains a change you have made (e.g.,
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because you mailed a patch which was applied upstream), then that commit
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will be skipped. For example, running `git rebase master` on the
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following history (in which `A'` and `A` introduce the same set of changes,
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but have different committer information):
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------------
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A---B---C topic
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/
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D---E---A'---F master
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------------
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will result in:
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------------
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B'---C' topic
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/
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D---E---A'---F master
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------------
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Here is how you would transplant a topic branch based on one
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branch to another, to pretend that you forked the topic branch
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from the latter branch, using `rebase --onto`.
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First let's assume your 'topic' is based on branch 'next'.
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For example, a feature developed in 'topic' depends on some
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functionality which is found in 'next'.
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------------
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o---o---o---o---o master
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\
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o---o---o---o---o next
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\
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o---o---o topic
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------------
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We want to make 'topic' forked from branch 'master'; for example,
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because the functionality on which 'topic' depends was merged into the
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more stable 'master' branch. We want our tree to look like this:
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------------
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o---o---o---o---o master
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| \
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| o'--o'--o' topic
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\
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o---o---o---o---o next
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------------
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We can get this using the following command:
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git rebase --onto master next topic
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Another example of --onto option is to rebase part of a
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branch. If we have the following situation:
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------------
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H---I---J topicB
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/
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E---F---G topicA
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/
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A---B---C---D master
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------------
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then the command
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git rebase --onto master topicA topicB
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would result in:
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------------
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H'--I'--J' topicB
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/
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| E---F---G topicA
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|/
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A---B---C---D master
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------------
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This is useful when topicB does not depend on topicA.
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A range of commits could also be removed with rebase. If we have
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the following situation:
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------------
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E---F---G---H---I---J topicA
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------------
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then the command
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git rebase --onto topicA~5 topicA~3 topicA
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would result in the removal of commits F and G:
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------------
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E---H'---I'---J' topicA
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------------
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This is useful if F and G were flawed in some way, or should not be
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part of topicA. Note that the argument to --onto and the <upstream>
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parameter can be any valid commit-ish.
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In case of conflict, 'git rebase' will stop at the first problematic commit
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and leave conflict markers in the tree. You can use 'git diff' to locate
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the markers (<<<<<<) and make edits to resolve the conflict. For each
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file you edit, you need to tell Git that the conflict has been resolved,
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typically this would be done with
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git add <filename>
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After resolving the conflict manually and updating the index with the
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desired resolution, you can continue the rebasing process with
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git rebase --continue
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Alternatively, you can undo the 'git rebase' with
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git rebase --abort
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CONFIGURATION
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-------------
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include::config/rebase.txt[]
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OPTIONS
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-------
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--onto <newbase>::
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Starting point at which to create the new commits. If the
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--onto option is not specified, the starting point is
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<upstream>. May be any valid commit, and not just an
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existing branch name.
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+
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As a special case, you may use "A\...B" as a shortcut for the
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merge base of A and B if there is exactly one merge base. You can
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leave out at most one of A and B, in which case it defaults to HEAD.
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--keep-base::
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Set the starting point at which to create the new commits to the
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merge base of <upstream> <branch>. Running
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'git rebase --keep-base <upstream> <branch>' is equivalent to
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running 'git rebase --onto <upstream>... <upstream>'.
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+
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This option is useful in the case where one is developing a feature on
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top of an upstream branch. While the feature is being worked on, the
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upstream branch may advance and it may not be the best idea to keep
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rebasing on top of the upstream but to keep the base commit as-is.
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+
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Although both this option and --fork-point find the merge base between
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<upstream> and <branch>, this option uses the merge base as the _starting
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point_ on which new commits will be created, whereas --fork-point uses
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the merge base to determine the _set of commits_ which will be rebased.
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+
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See also INCOMPATIBLE OPTIONS below.
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<upstream>::
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Upstream branch to compare against. May be any valid commit,
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not just an existing branch name. Defaults to the configured
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upstream for the current branch.
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<branch>::
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Working branch; defaults to HEAD.
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--continue::
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Restart the rebasing process after having resolved a merge conflict.
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--abort::
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Abort the rebase operation and reset HEAD to the original
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branch. If <branch> was provided when the rebase operation was
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started, then HEAD will be reset to <branch>. Otherwise HEAD
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will be reset to where it was when the rebase operation was
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started.
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--quit::
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Abort the rebase operation but HEAD is not reset back to the
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original branch. The index and working tree are also left
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unchanged as a result.
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--apply:
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Use applying strategies to rebase (calling `git-am`
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internally). This option may become a no-op in the future
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once the merge backend handles everything the apply one does.
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+
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See also INCOMPATIBLE OPTIONS below.
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--empty={drop,keep,ask}::
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How to handle commits that are not empty to start and are not
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clean cherry-picks of any upstream commit, but which become
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empty after rebasing (because they contain a subset of already
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upstream changes). With drop (the default), commits that
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become empty are dropped. With keep, such commits are kept.
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With ask (implied by --interactive), the rebase will halt when
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an empty commit is applied allowing you to choose whether to
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drop it, edit files more, or just commit the empty changes.
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Other options, like --exec, will use the default of drop unless
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-i/--interactive is explicitly specified.
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+
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Note that commits which start empty are kept, and commits which are
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clean cherry-picks (as determined by `git log --cherry-mark ...`) are
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always dropped.
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+
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See also INCOMPATIBLE OPTIONS below.
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--keep-empty::
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No-op. Rebasing commits that started empty (had no change
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relative to their parent) used to fail and this option would
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override that behavior, allowing commits with empty changes to
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be rebased. Now commits with no changes do not cause rebasing
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to halt.
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+
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See also BEHAVIORAL DIFFERENCES and INCOMPATIBLE OPTIONS below.
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--allow-empty-message::
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No-op. Rebasing commits with an empty message used to fail
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and this option would override that behavior, allowing commits
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with empty messages to be rebased. Now commits with an empty
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message do not cause rebasing to halt.
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+
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See also INCOMPATIBLE OPTIONS below.
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--skip::
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Restart the rebasing process by skipping the current patch.
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--edit-todo::
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Edit the todo list during an interactive rebase.
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--show-current-patch::
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Show the current patch in an interactive rebase or when rebase
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is stopped because of conflicts. This is the equivalent of
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`git show REBASE_HEAD`.
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-m::
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--merge::
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Use merging strategies to rebase. When the recursive (default) merge
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strategy is used, this allows rebase to be aware of renames on the
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upstream side. This is the default.
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+
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Note that a rebase merge works by replaying each commit from the working
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branch on top of the <upstream> branch. Because of this, when a merge
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conflict happens, the side reported as 'ours' is the so-far rebased
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series, starting with <upstream>, and 'theirs' is the working branch. In
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other words, the sides are swapped.
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+
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See also INCOMPATIBLE OPTIONS below.
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-s <strategy>::
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--strategy=<strategy>::
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Use the given merge strategy.
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If there is no `-s` option 'git merge-recursive' is used
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instead. This implies --merge.
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+
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Because 'git rebase' replays each commit from the working branch
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on top of the <upstream> branch using the given strategy, using
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the 'ours' strategy simply empties all patches from the <branch>,
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which makes little sense.
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+
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See also INCOMPATIBLE OPTIONS below.
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-X <strategy-option>::
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--strategy-option=<strategy-option>::
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Pass the <strategy-option> through to the merge strategy.
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This implies `--merge` and, if no strategy has been
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specified, `-s recursive`. Note the reversal of 'ours' and
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'theirs' as noted above for the `-m` option.
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+
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See also INCOMPATIBLE OPTIONS below.
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--rerere-autoupdate::
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--no-rerere-autoupdate::
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Allow the rerere mechanism to update the index with the
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result of auto-conflict resolution if possible.
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-S[<keyid>]::
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--gpg-sign[=<keyid>]::
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GPG-sign commits. The `keyid` argument is optional and
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defaults to the committer identity; if specified, it must be
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stuck to the option without a space.
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-q::
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--quiet::
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Be quiet. Implies --no-stat.
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-v::
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--verbose::
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Be verbose. Implies --stat.
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--stat::
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Show a diffstat of what changed upstream since the last rebase. The
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diffstat is also controlled by the configuration option rebase.stat.
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-n::
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--no-stat::
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Do not show a diffstat as part of the rebase process.
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--no-verify::
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This option bypasses the pre-rebase hook. See also linkgit:githooks[5].
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--verify::
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Allows the pre-rebase hook to run, which is the default. This option can
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be used to override --no-verify. See also linkgit:githooks[5].
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-C<n>::
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Ensure at least <n> lines of surrounding context match before
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and after each change. When fewer lines of surrounding
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context exist they all must match. By default no context is
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ever ignored. Implies --apply.
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+
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See also INCOMPATIBLE OPTIONS below.
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--no-ff::
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--force-rebase::
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-f::
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Individually replay all rebased commits instead of fast-forwarding
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over the unchanged ones. This ensures that the entire history of
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the rebased branch is composed of new commits.
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+
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You may find this helpful after reverting a topic branch merge, as this option
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recreates the topic branch with fresh commits so it can be remerged
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successfully without needing to "revert the reversion" (see the
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link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for
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details).
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--fork-point::
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--no-fork-point::
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Use reflog to find a better common ancestor between <upstream>
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and <branch> when calculating which commits have been
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introduced by <branch>.
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+
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When --fork-point is active, 'fork_point' will be used instead of
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<upstream> to calculate the set of commits to rebase, where
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'fork_point' is the result of `git merge-base --fork-point <upstream>
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<branch>` command (see linkgit:git-merge-base[1]). If 'fork_point'
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ends up being empty, the <upstream> will be used as a fallback.
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+
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If either <upstream> or --root is given on the command line, then the
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default is `--no-fork-point`, otherwise the default is `--fork-point`.
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+
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If your branch was based on <upstream> but <upstream> was rewound and
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your branch contains commits which were dropped, this option can be used
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with `--keep-base` in order to drop those commits from your branch.
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--ignore-whitespace::
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--whitespace=<option>::
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These flags are passed to the 'git apply' program
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(see linkgit:git-apply[1]) that applies the patch.
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Implies --apply.
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+
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See also INCOMPATIBLE OPTIONS below.
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--committer-date-is-author-date::
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--ignore-date::
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These flags are passed to 'git am' to easily change the dates
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of the rebased commits (see linkgit:git-am[1]).
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+
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See also INCOMPATIBLE OPTIONS below.
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--signoff::
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Add a Signed-off-by: trailer to all the rebased commits. Note
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that if `--interactive` is given then only commits marked to be
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picked, edited or reworded will have the trailer added.
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+
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See also INCOMPATIBLE OPTIONS below.
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-i::
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--interactive::
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Make a list of the commits which are about to be rebased. Let the
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user edit that list before rebasing. This mode can also be used to
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split commits (see SPLITTING COMMITS below).
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+
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The commit list format can be changed by setting the configuration option
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rebase.instructionFormat. A customized instruction format will automatically
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have the long commit hash prepended to the format.
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+
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See also INCOMPATIBLE OPTIONS below.
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-r::
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--rebase-merges[=(rebase-cousins|no-rebase-cousins)]::
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By default, a rebase will simply drop merge commits from the todo
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list, and put the rebased commits into a single, linear branch.
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With `--rebase-merges`, the rebase will instead try to preserve
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the branching structure within the commits that are to be rebased,
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by recreating the merge commits. Any resolved merge conflicts or
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manual amendments in these merge commits will have to be
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resolved/re-applied manually.
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+
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By default, or when `no-rebase-cousins` was specified, commits which do not
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have `<upstream>` as direct ancestor will keep their original branch point,
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i.e. commits that would be excluded by linkgit:git-log[1]'s
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`--ancestry-path` option will keep their original ancestry by default. If
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the `rebase-cousins` mode is turned on, such commits are instead rebased
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onto `<upstream>` (or `<onto>`, if specified).
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+
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The `--rebase-merges` mode is similar in spirit to the deprecated
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`--preserve-merges` but works with interactive rebases,
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where commits can be reordered, inserted and dropped at will.
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+
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It is currently only possible to recreate the merge commits using the
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`recursive` merge strategy; Different merge strategies can be used only via
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explicit `exec git merge -s <strategy> [...]` commands.
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+
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See also REBASING MERGES and INCOMPATIBLE OPTIONS below.
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-p::
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--preserve-merges::
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[DEPRECATED: use `--rebase-merges` instead] Recreate merge commits
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instead of flattening the history by replaying commits a merge commit
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introduces. Merge conflict resolutions or manual amendments to merge
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commits are not preserved.
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+
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This uses the `--interactive` machinery internally, but combining it
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with the `--interactive` option explicitly is generally not a good
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idea unless you know what you are doing (see BUGS below).
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+
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See also INCOMPATIBLE OPTIONS below.
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-x <cmd>::
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--exec <cmd>::
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Append "exec <cmd>" after each line creating a commit in the
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final history. <cmd> will be interpreted as one or more shell
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commands. Any command that fails will interrupt the rebase,
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with exit code 1.
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+
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You may execute several commands by either using one instance of `--exec`
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with several commands:
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+
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git rebase -i --exec "cmd1 && cmd2 && ..."
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+
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or by giving more than one `--exec`:
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+
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git rebase -i --exec "cmd1" --exec "cmd2" --exec ...
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+
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If `--autosquash` is used, "exec" lines will not be appended for
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the intermediate commits, and will only appear at the end of each
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|
squash/fixup series.
|
|
+
|
|
This uses the `--interactive` machinery internally, but it can be run
|
|
without an explicit `--interactive`.
|
|
+
|
|
See also INCOMPATIBLE OPTIONS below.
|
|
|
|
--root::
|
|
Rebase all commits reachable from <branch>, instead of
|
|
limiting them with an <upstream>. This allows you to rebase
|
|
the root commit(s) on a branch. When used with --onto, it
|
|
will skip changes already contained in <newbase> (instead of
|
|
<upstream>) whereas without --onto it will operate on every change.
|
|
When used together with both --onto and --preserve-merges,
|
|
'all' root commits will be rewritten to have <newbase> as parent
|
|
instead.
|
|
+
|
|
See also INCOMPATIBLE OPTIONS below.
|
|
|
|
--autosquash::
|
|
--no-autosquash::
|
|
When the commit log message begins with "squash! ..." (or
|
|
"fixup! ..."), and there is already a commit in the todo list that
|
|
matches the same `...`, automatically modify the todo list of rebase
|
|
-i so that the commit marked for squashing comes right after the
|
|
commit to be modified, and change the action of the moved commit
|
|
from `pick` to `squash` (or `fixup`). A commit matches the `...` if
|
|
the commit subject matches, or if the `...` refers to the commit's
|
|
hash. As a fall-back, partial matches of the commit subject work,
|
|
too. The recommended way to create fixup/squash commits is by using
|
|
the `--fixup`/`--squash` options of linkgit:git-commit[1].
|
|
+
|
|
If the `--autosquash` option is enabled by default using the
|
|
configuration variable `rebase.autoSquash`, this option can be
|
|
used to override and disable this setting.
|
|
+
|
|
See also INCOMPATIBLE OPTIONS below.
|
|
|
|
--autostash::
|
|
--no-autostash::
|
|
Automatically create a temporary stash entry before the operation
|
|
begins, and apply it after the operation ends. This means
|
|
that you can run rebase on a dirty worktree. However, use
|
|
with care: the final stash application after a successful
|
|
rebase might result in non-trivial conflicts.
|
|
|
|
--reschedule-failed-exec::
|
|
--no-reschedule-failed-exec::
|
|
Automatically reschedule `exec` commands that failed. This only makes
|
|
sense in interactive mode (or when an `--exec` option was provided).
|
|
|
|
INCOMPATIBLE OPTIONS
|
|
--------------------
|
|
|
|
The following options:
|
|
|
|
* --apply
|
|
* --committer-date-is-author-date
|
|
* --ignore-date
|
|
* --ignore-whitespace
|
|
* --whitespace
|
|
* -C
|
|
|
|
are incompatible with the following options:
|
|
|
|
* --merge
|
|
* --strategy
|
|
* --strategy-option
|
|
* --allow-empty-message
|
|
* --[no-]autosquash
|
|
* --rebase-merges
|
|
* --preserve-merges
|
|
* --interactive
|
|
* --exec
|
|
* --keep-empty
|
|
* --empty=
|
|
* --edit-todo
|
|
* --root when used in combination with --onto
|
|
|
|
In addition, the following pairs of options are incompatible:
|
|
|
|
* --preserve-merges and --interactive
|
|
* --preserve-merges and --signoff
|
|
* --preserve-merges and --rebase-merges
|
|
* --preserve-merges and --empty=
|
|
* --keep-base and --onto
|
|
* --keep-base and --root
|
|
|
|
BEHAVIORAL DIFFERENCES
|
|
-----------------------
|
|
|
|
git rebase has two primary backends: apply and merge. (The apply
|
|
backend used to known as the 'am' backend, but the name led to
|
|
confusion as it looks like a verb instead of a noun. Also, the merge
|
|
backend used to be known as the interactive backend, but it is now
|
|
used for non-interactive cases as well. Both were renamed based on
|
|
lower-level functionality that underpinned each.) There are some
|
|
subtle differences in how these two backends behave:
|
|
|
|
Empty commits
|
|
~~~~~~~~~~~~~
|
|
|
|
The apply backend unfortunately drops intentionally empty commits, i.e.
|
|
commits that started empty, though these are rare in practice. It
|
|
also drops commits that become empty and has no option for controlling
|
|
this behavior.
|
|
|
|
The merge backend keeps intentionally empty commits. Similar to the
|
|
apply backend, by default the merge backend drops commits that become
|
|
empty unless -i/--interactive is specified (in which case it stops and
|
|
asks the user what to do). The merge backend also has an
|
|
--empty={drop,keep,ask} option for changing the behavior of handling
|
|
commits that become empty.
|
|
|
|
Directory rename detection
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Due to the lack of accurate tree information (arising from
|
|
constructing fake ancestors with the limited information available in
|
|
patches), directory rename detection is disabled in the apply backend.
|
|
Disabled directory rename detection means that if one side of history
|
|
renames a directory and the other adds new files to the old directory,
|
|
then the new files will be left behind in the old directory without
|
|
any warning at the time of rebasing that you may want to move these
|
|
files into the new directory.
|
|
|
|
Directory rename detection works with the merge backend to provide you
|
|
warnings in such cases.
|
|
|
|
Context
|
|
~~~~~~~
|
|
|
|
The apply backend works by creating a sequence of patches (by calling
|
|
`format-patch` internally), and then applying the patches in sequence
|
|
(calling `am` internally). Patches are composed of multiple hunks,
|
|
each with line numbers, a context region, and the actual changes. The
|
|
line numbers have to be taken with some fuzz, since the other side
|
|
will likely have inserted or deleted lines earlier in the file. The
|
|
context region is meant to help find how to adjust the line numbers in
|
|
order to apply the changes to the right lines. However, if multiple
|
|
areas of the code have the same surrounding lines of context, the
|
|
wrong one can be picked. There are real-world cases where this has
|
|
caused commits to be reapplied incorrectly with no conflicts reported.
|
|
Setting diff.context to a larger value may prevent such types of
|
|
problems, but increases the chance of spurious conflicts (since it
|
|
will require more lines of matching context to apply).
|
|
|
|
The merge backend works with a full copy of each relevant file,
|
|
insulating it from these types of problems.
|
|
|
|
Labelling of conflicts markers
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
When there are content conflicts, the merge machinery tries to
|
|
annotate each side's conflict markers with the commits where the
|
|
content came from. Since the apply backend drops the original
|
|
information about the rebased commits and their parents (and instead
|
|
generates new fake commits based off limited information in the
|
|
generated patches), those commits cannot be identified; instead it has
|
|
to fall back to a commit summary. Also, when merge.conflictStyle is
|
|
set to diff3, the apply backend will use "constructed merge base" to
|
|
label the content from the merge base, and thus provide no information
|
|
about the merge base commit whatsoever.
|
|
|
|
The merge backend works with the full commits on both sides of history
|
|
and thus has no such limitations.
|
|
|
|
Hooks
|
|
~~~~~
|
|
|
|
The apply backend has not traditionally called the post-commit hook,
|
|
while the merge backend has. However, this was by accident of
|
|
implementation rather than by design. Both backends should have the
|
|
same behavior, though it is not clear which one is correct.
|
|
|
|
Interruptability
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
The apply backend has safety problems with an ill-timed interrupt; if
|
|
the user presses Ctrl-C at the wrong time to try to abort the rebase,
|
|
the rebase can enter a state where it cannot be aborted with a
|
|
subsequent `git rebase --abort`. The merge backend does not appear to
|
|
suffer from the same shortcoming. (See
|
|
https://lore.kernel.org/git/20200207132152.GC2868@szeder.dev/ for
|
|
details.)
|
|
|
|
Commit Rewording
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
When a conflict occurs while rebasing, rebase stops and asks the user
|
|
to resolve. Since the user may need to make notable changes while
|
|
resolving conflicts, after conflicts are resolved and the user has run
|
|
`git rebase --continue`, the rebase should open an editor and ask the
|
|
user to update the commit message. The merge backend does this, while
|
|
the apply backend blindly applies the original commit message.
|
|
|
|
Miscellaneous differences
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
There are a few more behavioral differences that most folks would
|
|
probably consider inconsequential but which are mentioned for
|
|
completeness:
|
|
|
|
* Reflog: The two backends will use different wording when describing
|
|
the changes made in the reflog, though both will make use of the
|
|
word "rebase".
|
|
|
|
* Progress, informational, and error messages: The two backends
|
|
provide slightly different progress and informational messages.
|
|
Also, the apply backend writes error messages (such as "Your files
|
|
would be overwritten...") to stdout, while the merge backend writes
|
|
them to stderr.
|
|
|
|
* State directories: The two backends keep their state in different
|
|
directories under .git/
|
|
|
|
include::merge-strategies.txt[]
|
|
|
|
NOTES
|
|
-----
|
|
|
|
You should understand the implications of using 'git rebase' on a
|
|
repository that you share. See also RECOVERING FROM UPSTREAM REBASE
|
|
below.
|
|
|
|
When the git-rebase command is run, it will first execute a "pre-rebase"
|
|
hook if one exists. You can use this hook to do sanity checks and
|
|
reject the rebase if it isn't appropriate. Please see the template
|
|
pre-rebase hook script for an example.
|
|
|
|
Upon completion, <branch> will be the current branch.
|
|
|
|
INTERACTIVE MODE
|
|
----------------
|
|
|
|
Rebasing interactively means that you have a chance to edit the commits
|
|
which are rebased. You can reorder the commits, and you can
|
|
remove them (weeding out bad or otherwise unwanted patches).
|
|
|
|
The interactive mode is meant for this type of workflow:
|
|
|
|
1. have a wonderful idea
|
|
2. hack on the code
|
|
3. prepare a series for submission
|
|
4. submit
|
|
|
|
where point 2. consists of several instances of
|
|
|
|
a) regular use
|
|
|
|
1. finish something worthy of a commit
|
|
2. commit
|
|
|
|
b) independent fixup
|
|
|
|
1. realize that something does not work
|
|
2. fix that
|
|
3. commit it
|
|
|
|
Sometimes the thing fixed in b.2. cannot be amended to the not-quite
|
|
perfect commit it fixes, because that commit is buried deeply in a
|
|
patch series. That is exactly what interactive rebase is for: use it
|
|
after plenty of "a"s and "b"s, by rearranging and editing
|
|
commits, and squashing multiple commits into one.
|
|
|
|
Start it with the last commit you want to retain as-is:
|
|
|
|
git rebase -i <after-this-commit>
|
|
|
|
An editor will be fired up with all the commits in your current branch
|
|
(ignoring merge commits), which come after the given commit. You can
|
|
reorder the commits in this list to your heart's content, and you can
|
|
remove them. The list looks more or less like this:
|
|
|
|
-------------------------------------------
|
|
pick deadbee The oneline of this commit
|
|
pick fa1afe1 The oneline of the next commit
|
|
...
|
|
-------------------------------------------
|
|
|
|
The oneline descriptions are purely for your pleasure; 'git rebase' will
|
|
not look at them but at the commit names ("deadbee" and "fa1afe1" in this
|
|
example), so do not delete or edit the names.
|
|
|
|
By replacing the command "pick" with the command "edit", you can tell
|
|
'git rebase' to stop after applying that commit, so that you can edit
|
|
the files and/or the commit message, amend the commit, and continue
|
|
rebasing.
|
|
|
|
To interrupt the rebase (just like an "edit" command would do, but without
|
|
cherry-picking any commit first), use the "break" command.
|
|
|
|
If you just want to edit the commit message for a commit, replace the
|
|
command "pick" with the command "reword".
|
|
|
|
To drop a commit, replace the command "pick" with "drop", or just
|
|
delete the matching line.
|
|
|
|
If you want to fold two or more commits into one, replace the command
|
|
"pick" for the second and subsequent commits with "squash" or "fixup".
|
|
If the commits had different authors, the folded commit will be
|
|
attributed to the author of the first commit. The suggested commit
|
|
message for the folded commit is the concatenation of the commit
|
|
messages of the first commit and of those with the "squash" command,
|
|
but omits the commit messages of commits with the "fixup" command.
|
|
|
|
'git rebase' will stop when "pick" has been replaced with "edit" or
|
|
when a command fails due to merge errors. When you are done editing
|
|
and/or resolving conflicts you can continue with `git rebase --continue`.
|
|
|
|
For example, if you want to reorder the last 5 commits, such that what
|
|
was HEAD~4 becomes the new HEAD. To achieve that, you would call
|
|
'git rebase' like this:
|
|
|
|
----------------------
|
|
$ git rebase -i HEAD~5
|
|
----------------------
|
|
|
|
And move the first patch to the end of the list.
|
|
|
|
You might want to recreate merge commits, e.g. if you have a history
|
|
like this:
|
|
|
|
------------------
|
|
X
|
|
\
|
|
A---M---B
|
|
/
|
|
---o---O---P---Q
|
|
------------------
|
|
|
|
Suppose you want to rebase the side branch starting at "A" to "Q". Make
|
|
sure that the current HEAD is "B", and call
|
|
|
|
-----------------------------
|
|
$ git rebase -i -r --onto Q O
|
|
-----------------------------
|
|
|
|
Reordering and editing commits usually creates untested intermediate
|
|
steps. You may want to check that your history editing did not break
|
|
anything by running a test, or at least recompiling at intermediate
|
|
points in history by using the "exec" command (shortcut "x"). You may
|
|
do so by creating a todo list like this one:
|
|
|
|
-------------------------------------------
|
|
pick deadbee Implement feature XXX
|
|
fixup f1a5c00 Fix to feature XXX
|
|
exec make
|
|
pick c0ffeee The oneline of the next commit
|
|
edit deadbab The oneline of the commit after
|
|
exec cd subdir; make test
|
|
...
|
|
-------------------------------------------
|
|
|
|
The interactive rebase will stop when a command fails (i.e. exits with
|
|
non-0 status) to give you an opportunity to fix the problem. You can
|
|
continue with `git rebase --continue`.
|
|
|
|
The "exec" command launches the command in a shell (the one specified
|
|
in `$SHELL`, or the default shell if `$SHELL` is not set), so you can
|
|
use shell features (like "cd", ">", ";" ...). The command is run from
|
|
the root of the working tree.
|
|
|
|
----------------------------------
|
|
$ git rebase -i --exec "make test"
|
|
----------------------------------
|
|
|
|
This command lets you check that intermediate commits are compilable.
|
|
The todo list becomes like that:
|
|
|
|
--------------------
|
|
pick 5928aea one
|
|
exec make test
|
|
pick 04d0fda two
|
|
exec make test
|
|
pick ba46169 three
|
|
exec make test
|
|
pick f4593f9 four
|
|
exec make test
|
|
--------------------
|
|
|
|
SPLITTING COMMITS
|
|
-----------------
|
|
|
|
In interactive mode, you can mark commits with the action "edit". However,
|
|
this does not necessarily mean that 'git rebase' expects the result of this
|
|
edit to be exactly one commit. Indeed, you can undo the commit, or you can
|
|
add other commits. This can be used to split a commit into two:
|
|
|
|
- Start an interactive rebase with `git rebase -i <commit>^`, where
|
|
<commit> is the commit you want to split. In fact, any commit range
|
|
will do, as long as it contains that commit.
|
|
|
|
- Mark the commit you want to split with the action "edit".
|
|
|
|
- When it comes to editing that commit, execute `git reset HEAD^`. The
|
|
effect is that the HEAD is rewound by one, and the index follows suit.
|
|
However, the working tree stays the same.
|
|
|
|
- Now add the changes to the index that you want to have in the first
|
|
commit. You can use `git add` (possibly interactively) or
|
|
'git gui' (or both) to do that.
|
|
|
|
- Commit the now-current index with whatever commit message is appropriate
|
|
now.
|
|
|
|
- Repeat the last two steps until your working tree is clean.
|
|
|
|
- Continue the rebase with `git rebase --continue`.
|
|
|
|
If you are not absolutely sure that the intermediate revisions are
|
|
consistent (they compile, pass the testsuite, etc.) you should use
|
|
'git stash' to stash away the not-yet-committed changes
|
|
after each commit, test, and amend the commit if fixes are necessary.
|
|
|
|
|
|
RECOVERING FROM UPSTREAM REBASE
|
|
-------------------------------
|
|
|
|
Rebasing (or any other form of rewriting) a branch that others have
|
|
based work on is a bad idea: anyone downstream of it is forced to
|
|
manually fix their history. This section explains how to do the fix
|
|
from the downstream's point of view. The real fix, however, would be
|
|
to avoid rebasing the upstream in the first place.
|
|
|
|
To illustrate, suppose you are in a situation where someone develops a
|
|
'subsystem' branch, and you are working on a 'topic' that is dependent
|
|
on this 'subsystem'. You might end up with a history like the
|
|
following:
|
|
|
|
------------
|
|
o---o---o---o---o---o---o---o master
|
|
\
|
|
o---o---o---o---o subsystem
|
|
\
|
|
*---*---* topic
|
|
------------
|
|
|
|
If 'subsystem' is rebased against 'master', the following happens:
|
|
|
|
------------
|
|
o---o---o---o---o---o---o---o master
|
|
\ \
|
|
o---o---o---o---o o'--o'--o'--o'--o' subsystem
|
|
\
|
|
*---*---* topic
|
|
------------
|
|
|
|
If you now continue development as usual, and eventually merge 'topic'
|
|
to 'subsystem', the commits from 'subsystem' will remain duplicated forever:
|
|
|
|
------------
|
|
o---o---o---o---o---o---o---o master
|
|
\ \
|
|
o---o---o---o---o o'--o'--o'--o'--o'--M subsystem
|
|
\ /
|
|
*---*---*-..........-*--* topic
|
|
------------
|
|
|
|
Such duplicates are generally frowned upon because they clutter up
|
|
history, making it harder to follow. To clean things up, you need to
|
|
transplant the commits on 'topic' to the new 'subsystem' tip, i.e.,
|
|
rebase 'topic'. This becomes a ripple effect: anyone downstream from
|
|
'topic' is forced to rebase too, and so on!
|
|
|
|
There are two kinds of fixes, discussed in the following subsections:
|
|
|
|
Easy case: The changes are literally the same.::
|
|
|
|
This happens if the 'subsystem' rebase was a simple rebase and
|
|
had no conflicts.
|
|
|
|
Hard case: The changes are not the same.::
|
|
|
|
This happens if the 'subsystem' rebase had conflicts, or used
|
|
`--interactive` to omit, edit, squash, or fixup commits; or
|
|
if the upstream used one of `commit --amend`, `reset`, or
|
|
a full history rewriting command like
|
|
https://github.com/newren/git-filter-repo[`filter-repo`].
|
|
|
|
|
|
The easy case
|
|
~~~~~~~~~~~~~
|
|
|
|
Only works if the changes (patch IDs based on the diff contents) on
|
|
'subsystem' are literally the same before and after the rebase
|
|
'subsystem' did.
|
|
|
|
In that case, the fix is easy because 'git rebase' knows to skip
|
|
changes that are already present in the new upstream. So if you say
|
|
(assuming you're on 'topic')
|
|
------------
|
|
$ git rebase subsystem
|
|
------------
|
|
you will end up with the fixed history
|
|
------------
|
|
o---o---o---o---o---o---o---o master
|
|
\
|
|
o'--o'--o'--o'--o' subsystem
|
|
\
|
|
*---*---* topic
|
|
------------
|
|
|
|
|
|
The hard case
|
|
~~~~~~~~~~~~~
|
|
|
|
Things get more complicated if the 'subsystem' changes do not exactly
|
|
correspond to the ones before the rebase.
|
|
|
|
NOTE: While an "easy case recovery" sometimes appears to be successful
|
|
even in the hard case, it may have unintended consequences. For
|
|
example, a commit that was removed via `git rebase
|
|
--interactive` will be **resurrected**!
|
|
|
|
The idea is to manually tell 'git rebase' "where the old 'subsystem'
|
|
ended and your 'topic' began", that is, what the old merge base
|
|
between them was. You will have to find a way to name the last commit
|
|
of the old 'subsystem', for example:
|
|
|
|
* With the 'subsystem' reflog: after 'git fetch', the old tip of
|
|
'subsystem' is at `subsystem@{1}`. Subsequent fetches will
|
|
increase the number. (See linkgit:git-reflog[1].)
|
|
|
|
* Relative to the tip of 'topic': knowing that your 'topic' has three
|
|
commits, the old tip of 'subsystem' must be `topic~3`.
|
|
|
|
You can then transplant the old `subsystem..topic` to the new tip by
|
|
saying (for the reflog case, and assuming you are on 'topic' already):
|
|
------------
|
|
$ git rebase --onto subsystem subsystem@{1}
|
|
------------
|
|
|
|
The ripple effect of a "hard case" recovery is especially bad:
|
|
'everyone' downstream from 'topic' will now have to perform a "hard
|
|
case" recovery too!
|
|
|
|
REBASING MERGES
|
|
---------------
|
|
|
|
The interactive rebase command was originally designed to handle
|
|
individual patch series. As such, it makes sense to exclude merge
|
|
commits from the todo list, as the developer may have merged the
|
|
then-current `master` while working on the branch, only to rebase
|
|
all the commits onto `master` eventually (skipping the merge
|
|
commits).
|
|
|
|
However, there are legitimate reasons why a developer may want to
|
|
recreate merge commits: to keep the branch structure (or "commit
|
|
topology") when working on multiple, inter-related branches.
|
|
|
|
In the following example, the developer works on a topic branch that
|
|
refactors the way buttons are defined, and on another topic branch
|
|
that uses that refactoring to implement a "Report a bug" button. The
|
|
output of `git log --graph --format=%s -5` may look like this:
|
|
|
|
------------
|
|
* Merge branch 'report-a-bug'
|
|
|\
|
|
| * Add the feedback button
|
|
* | Merge branch 'refactor-button'
|
|
|\ \
|
|
| |/
|
|
| * Use the Button class for all buttons
|
|
| * Extract a generic Button class from the DownloadButton one
|
|
------------
|
|
|
|
The developer might want to rebase those commits to a newer `master`
|
|
while keeping the branch topology, for example when the first topic
|
|
branch is expected to be integrated into `master` much earlier than the
|
|
second one, say, to resolve merge conflicts with changes to the
|
|
DownloadButton class that made it into `master`.
|
|
|
|
This rebase can be performed using the `--rebase-merges` option.
|
|
It will generate a todo list looking like this:
|
|
|
|
------------
|
|
label onto
|
|
|
|
# Branch: refactor-button
|
|
reset onto
|
|
pick 123456 Extract a generic Button class from the DownloadButton one
|
|
pick 654321 Use the Button class for all buttons
|
|
label refactor-button
|
|
|
|
# Branch: report-a-bug
|
|
reset refactor-button # Use the Button class for all buttons
|
|
pick abcdef Add the feedback button
|
|
label report-a-bug
|
|
|
|
reset onto
|
|
merge -C a1b2c3 refactor-button # Merge 'refactor-button'
|
|
merge -C 6f5e4d report-a-bug # Merge 'report-a-bug'
|
|
------------
|
|
|
|
In contrast to a regular interactive rebase, there are `label`, `reset`
|
|
and `merge` commands in addition to `pick` ones.
|
|
|
|
The `label` command associates a label with the current HEAD when that
|
|
command is executed. These labels are created as worktree-local refs
|
|
(`refs/rewritten/<label>`) that will be deleted when the rebase
|
|
finishes. That way, rebase operations in multiple worktrees linked to
|
|
the same repository do not interfere with one another. If the `label`
|
|
command fails, it is rescheduled immediately, with a helpful message how
|
|
to proceed.
|
|
|
|
The `reset` command resets the HEAD, index and worktree to the specified
|
|
revision. It is similar to an `exec git reset --hard <label>`, but
|
|
refuses to overwrite untracked files. If the `reset` command fails, it is
|
|
rescheduled immediately, with a helpful message how to edit the todo list
|
|
(this typically happens when a `reset` command was inserted into the todo
|
|
list manually and contains a typo).
|
|
|
|
The `merge` command will merge the specified revision(s) into whatever
|
|
is HEAD at that time. With `-C <original-commit>`, the commit message of
|
|
the specified merge commit will be used. When the `-C` is changed to
|
|
a lower-case `-c`, the message will be opened in an editor after a
|
|
successful merge so that the user can edit the message.
|
|
|
|
If a `merge` command fails for any reason other than merge conflicts (i.e.
|
|
when the merge operation did not even start), it is rescheduled immediately.
|
|
|
|
At this time, the `merge` command will *always* use the `recursive`
|
|
merge strategy for regular merges, and `octopus` for octopus merges,
|
|
with no way to choose a different one. To work around
|
|
this, an `exec` command can be used to call `git merge` explicitly,
|
|
using the fact that the labels are worktree-local refs (the ref
|
|
`refs/rewritten/onto` would correspond to the label `onto`, for example).
|
|
|
|
Note: the first command (`label onto`) labels the revision onto which
|
|
the commits are rebased; The name `onto` is just a convention, as a nod
|
|
to the `--onto` option.
|
|
|
|
It is also possible to introduce completely new merge commits from scratch
|
|
by adding a command of the form `merge <merge-head>`. This form will
|
|
generate a tentative commit message and always open an editor to let the
|
|
user edit it. This can be useful e.g. when a topic branch turns out to
|
|
address more than a single concern and wants to be split into two or
|
|
even more topic branches. Consider this todo list:
|
|
|
|
------------
|
|
pick 192837 Switch from GNU Makefiles to CMake
|
|
pick 5a6c7e Document the switch to CMake
|
|
pick 918273 Fix detection of OpenSSL in CMake
|
|
pick afbecd http: add support for TLS v1.3
|
|
pick fdbaec Fix detection of cURL in CMake on Windows
|
|
------------
|
|
|
|
The one commit in this list that is not related to CMake may very well
|
|
have been motivated by working on fixing all those bugs introduced by
|
|
switching to CMake, but it addresses a different concern. To split this
|
|
branch into two topic branches, the todo list could be edited like this:
|
|
|
|
------------
|
|
label onto
|
|
|
|
pick afbecd http: add support for TLS v1.3
|
|
label tlsv1.3
|
|
|
|
reset onto
|
|
pick 192837 Switch from GNU Makefiles to CMake
|
|
pick 918273 Fix detection of OpenSSL in CMake
|
|
pick fdbaec Fix detection of cURL in CMake on Windows
|
|
pick 5a6c7e Document the switch to CMake
|
|
label cmake
|
|
|
|
reset onto
|
|
merge tlsv1.3
|
|
merge cmake
|
|
------------
|
|
|
|
BUGS
|
|
----
|
|
The todo list presented by the deprecated `--preserve-merges --interactive`
|
|
does not represent the topology of the revision graph (use `--rebase-merges`
|
|
instead). Editing commits and rewording their commit messages should work
|
|
fine, but attempts to reorder commits tend to produce counterintuitive results.
|
|
Use `--rebase-merges` in such scenarios instead.
|
|
|
|
For example, an attempt to rearrange
|
|
------------
|
|
1 --- 2 --- 3 --- 4 --- 5
|
|
------------
|
|
to
|
|
------------
|
|
1 --- 2 --- 4 --- 3 --- 5
|
|
------------
|
|
by moving the "pick 4" line will result in the following history:
|
|
------------
|
|
3
|
|
/
|
|
1 --- 2 --- 4 --- 5
|
|
------------
|
|
|
|
GIT
|
|
---
|
|
Part of the linkgit:git[1] suite
|