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GIT\-REBASE

Section: Git Manual (1)
Updated: 09/30/2007
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NAME

git-rebase - Forward-port local commits to the updated upstream head  

SYNOPSIS

git-rebase [-i | --interactive] [-v | --verbose] [-m | --merge] [-C<n>]
        [-p | --preserve-merges] [--onto <newbase>] <upstream> [<branch>]
git-rebase --continue | --skip | --abort
 

DESCRIPTION

If <branch> is specified, git-rebase will perform an automatic git checkout <branch> before doing anything else. Otherwise it remains on the current branch.

All changes made by commits in the current branch but that are not in <upstream> are saved to a temporary area. This is the same set of commits that would be shown by git log <upstream>..HEAD.

The current branch is reset to <upstream>, or <newbase> if the --onto option was supplied. This has the exact same effect as git reset --hard <upstream> (or <newbase>).

The commits that were previously saved into the temporary area are then reapplied to the current branch, one by one, in order.

It is possible that a merge failure will prevent this process from being completely automatic. You will have to resolve any such merge failure and run git rebase --continue. Another option is to bypass the commit that caused the merge failure with git rebase --skip. To restore the original <branch> and remove the .dotest working files, use the command git rebase --abort instead.

Assume the following history exists and the current branch is "topic":


.ft C
          A---B---C topic
         /
    D---E---F---G master
.ft

From this point, the result of either of the following commands:

git-rebase master
git-rebase master topic
would be:


.ft C
                  A'--B'--C' topic
                 /
    D---E---F---G master
.ft

The latter form is just a short-hand of git checkout topic followed by git rebase master.

Here is how you would transplant a topic branch based on one branch to another, to pretend that you forked the topic branch from the latter branch, using rebase --onto.

First let's assume your topic is based on branch next. For example feature developed in topic depends on some functionality which is found in next.


.ft C
    o---o---o---o---o  master
         \
          o---o---o---o---o  next
                           \
                            o---o---o  topic
.ft

We would want to make topic forked from branch master, for example because the functionality topic branch depend on got merged into more stable master branch, like this:


.ft C
    o---o---o---o---o  master
        |            \
        |             o'--o'--o'  topic
         \
          o---o---o---o---o  next
.ft

We can get this using the following command:

git-rebase --onto master next topic
Another example of --onto option is to rebase part of a branch. If we have the following situation:


.ft C
                            H---I---J topicB
                           /
                  E---F---G  topicA
                 /
    A---B---C---D  master
.ft

then the command

git-rebase --onto master topicA topicB
would result in:


.ft C
                 H'--I'--J'  topicB
                /
                | E---F---G  topicA
                |/
    A---B---C---D  master
.ft

This is useful when topicB does not depend on topicA.

A range of commits could also be removed with rebase. If we have the following situation:


.ft C
    E---F---G---H---I---J  topicA
.ft

then the command

git-rebase --onto topicA~5 topicA~3 topicA
would result in the removal of commits F and G:


.ft C
    E---H'---I'---J'  topicA
.ft

This is useful if F and G were flawed in some way, or should not be part of topicA. Note that the argument to --onto and the <upstream> parameter can be any valid commit-ish.

In case of conflict, git-rebase will stop at the first problematic commit and leave conflict markers in the tree. You can use git diff to locate the markers (<<<<<<) and make edits to resolve the conflict. For each file you edit, you need to tell git that the conflict has been resolved, typically this would be done with

git add <filename>
After resolving the conflict manually and updating the index with the desired resolution, you can continue the rebasing process with

git rebase --continue
Alternatively, you can undo the git-rebase with

git rebase --abort
 

OPTIONS

<newbase>

Starting point at which to create the new commits. If the --onto option is not specified, the starting point is <upstream>. May be any valid commit, and not just an existing branch name.

<upstream>

Upstream branch to compare against. May be any valid commit, not just an existing branch name.

<branch>

Working branch; defaults to HEAD.

--continue

Restart the rebasing process after having resolved a merge conflict.

--abort

Restore the original branch and abort the rebase operation.

--skip

Restart the rebasing process by skipping the current patch.

-m, --merge

Use merging strategies to rebase. When the recursive (default) merge strategy is used, this allows rebase to be aware of renames on the upstream side.

-s <strategy>, --strategy=<strategy>

Use the given merge strategy; can be supplied more than once to specify them in the order they should be tried. If there is no -s option, a built-in list of strategies is used instead (git-merge-recursive when merging a single head, git-merge-octopus otherwise). This implies --merge.

-v, --verbose

Display a diffstat of what changed upstream since the last rebase.

-C<n>

Ensure at least <n> lines of surrounding context match before and after each change. When fewer lines of surrounding context exist they all must match. By default no context is ever ignored.

-i, --interactive

Make a list of the commits which are about to be rebased. Let the user edit that list before rebasing. This mode can also be used to split commits (see SPLITTING COMMITS below).

-p, --preserve-merges

Instead of ignoring merges, try to recreate them. This option only works in interactive mode.
 

MERGE STRATEGIES

resolve

This can only resolve two heads (i.e. the current branch and another branch you pulled from) using 3-way merge algorithm. It tries to carefully detect criss-cross merge ambiguities and is considered generally safe and fast.

recursive

This can only resolve two heads using 3-way merge algorithm. When there are more than one common ancestors that can be used for 3-way merge, it creates a merged tree of the common ancestors and uses that as the reference tree for the 3-way merge. This has been reported to result in fewer merge conflicts without causing mis-merges by tests done on actual merge commits taken from Linux 2.6 kernel development history. Additionally this can detect and handle merges involving renames. This is the default merge strategy when pulling or merging one branch.

octopus

This resolves more than two-head case, but refuses to do complex merge that needs manual resolution. It is primarily meant to be used for bundling topic branch heads together. This is the default merge strategy when pulling or merging more than one branches.

ours

This resolves any number of heads, but the result of the merge is always the current branch head. It is meant to be used to supersede old development history of side branches.
 

NOTES

When you rebase a branch, you are changing its history in a way that will cause problems for anyone who already has a copy of the branch in their repository and tries to pull updates from you. You should understand the implications of using git rebase on a repository that you share.

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.

You must be in the top directory of your project to start (or continue) a rebase. 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

1.regular use

1.finish something worthy of a commit
2.commit
2.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:


.ft C
pick deadbee The oneline of this commit
pick fa1afe1 The oneline of the next commit
...
.ft

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.

If you want to fold two or more commits into one, replace the command "pick" with "squash" for the second and subsequent commit. If the commits had different authors, it will attribute the squashed commit to the author of the last commit.

In both cases, or when a "pick" does not succeed (because of merge errors), the loop will stop to let you fix things, and you can continue the loop 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:


.ft C
$ git rebase -i HEAD~5
.ft

And move the first patch to the end of the list.

You might want to preserve merges, if you have a history like this:


.ft C
           X
            \
         A---M---B
        /
---o---O---P---Q
.ft

Suppose you want to rebase the side branch starting at "A" to "Q". Make sure that the current HEAD is "B", and call


.ft C
$ git rebase -i -p --onto Q O
.ft

 

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(1) (possibly interactively) and/or git-gui(1) 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(1) to stash away the not-yet-committed changes after each commit, test, and amend the commit if fixes are necessary.  

AUTHORS

Written by Junio C Hamano <junkio@cox.net> and Johannes E. Schindelin <johannes.schindelin@gmx.de>  

DOCUMENTATION

Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.  

GIT

Part of the git(7) suite


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
MERGE STRATEGIES
NOTES
INTERACTIVE MODE
SPLITTING COMMITS
AUTHORS
DOCUMENTATION
GIT




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