Tribblix: manual page: git-rebase.1

GIT-REBASE(1) Git Manual GIT-REBASE(1)

NAME

git-rebase - Reapply commits on top of another base tip

SYNOPSIS

DESCRIPTION

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

If <upstream> is not specified, the upstream configured in
branch.<name>.remote and branch.<name>.merge options will be used
(see git-config(1) for details) and the --fork-point option is
assumed. If you are currently not on any branch or if the current
branch does not have a configured upstream, the rebase will abort.

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; or by git
log 'fork_point'..HEAD, if --fork-point is active (see the
description on --fork-point below); or by git log HEAD, if the --root
option is specified.

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>). ORIG_HEAD is set to point at the
tip of the branch before the reset.

Note

ORIG_HEAD is not guaranteed to still point to the previous branch
tip at the end of the rebase if other commands that write that
pseudo-ref (e.g. git reset) are used during the rebase. The
previous branch tip, however, is accessible using the reflog of
the current branch (i.e. @{1}, see gitrevisions(7)).

The commits that were previously saved into the temporary area are
then reapplied to the current branch, one by one, in order. Note that
any commits in HEAD which introduce the same textual changes as a
commit in HEAD..<upstream> are omitted (i.e., a patch already
accepted upstream with a different commit message or timestamp will
be skipped).

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
check out the original <branch> and remove the .git/rebase-apply
working files, use the command git rebase --abort instead.

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

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

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

git rebase master
git rebase master topic

would be:

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

NOTE: The latter form is just a short-hand of git checkout topic
followed by git rebase master. When rebase exits topic will remain
the checked-out branch.

If the upstream branch already contains a change you have made (e.g.,
because you mailed a patch which was applied upstream), then that
commit will be skipped and warnings will be issued (if the merge
backend is used). For example, running git rebase master on the
following history (in which A' and A introduce the same set of
changes, but have different committer information):

A---B---C topic
/
D---E---A'---F master

will result in:

B'---C' topic
/
D---E---A'---F 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, a
feature developed in topic depends on some functionality which is
found in next.

o---o---o---o---o master
\
o---o---o---o---o next
\
o---o---o topic

We want to make topic forked from branch master; for example, because
the functionality on which topic depends was merged into the more
stable master branch. We want our tree to look like this:

o---o---o---o---o master
| \
| o'--o'--o' topic
\
o---o---o---o---o next

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:

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

then the command

git rebase --onto master topicA topicB

would result in:

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

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:

E---F---G---H---I---J topicA

then the command

git rebase --onto topicA~5 topicA~3 topicA

would result in the removal of commits F and G:

E---H'---I'---J' topicA

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

MODE OPTIONS

The options in this section cannot be used with any other option,
including not with each other:

--continue
Restart the rebasing process after having resolved a merge
conflict.

--skip
Restart the rebasing process by skipping the current patch.

--abort
Abort the rebase operation and reset HEAD to the original branch.
If <branch> was provided when the rebase operation was started,
then HEAD will be reset to <branch>. Otherwise HEAD will be reset
to where it was when the rebase operation was started.

--quit
Abort the rebase operation but HEAD is not reset back to the
original branch. The index and working tree are also left
unchanged as a result. If a temporary stash entry was created
using --autostash, it will be saved to the stash list.

--edit-todo
Edit the todo list during an interactive rebase.

--show-current-patch
Show the current patch in an interactive rebase or when rebase is
stopped because of conflicts. This is the equivalent of git show
REBASE_HEAD.

OPTIONS

--onto <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.

As a special case, you may use "A...B" as a shortcut for the
merge base of A and B if there is exactly one merge base. You can
leave out at most one of A and B, in which case it defaults to
HEAD.

--keep-base
Set the starting point at which to create the new commits to the
merge base of <upstream> and <branch>. Running git rebase
--keep-base <upstream> <branch> is equivalent to running git
rebase --reapply-cherry-picks --no-fork-point --onto
<upstream>...<branch> <upstream> <branch>.

This option is useful in the case where one is developing a
feature on top of an upstream branch. While the feature is being
worked on, the upstream branch may advance and it may not be the
best idea to keep rebasing on top of the upstream but to keep the
base commit as-is. As the base commit is unchanged this option
implies --reapply-cherry-picks to avoid losing commits.

Although both this option and --fork-point find the merge base
between <upstream> and <branch>, this option uses the merge base
as the starting point on which new commits will be created,
whereas --fork-point uses the merge base to determine the set of
commits which will be rebased.

See also INCOMPATIBLE OPTIONS below.

<upstream>
Upstream branch to compare against. May be any valid commit, not
just an existing branch name. Defaults to the configured upstream
for the current branch.

<branch>
Working branch; defaults to HEAD.

--apply
Use applying strategies to rebase (calling git-am internally).
This option may become a no-op in the future once the merge
backend handles everything the apply one does.

See also INCOMPATIBLE OPTIONS below.

--empty=(drop|keep|stop)
How to handle commits that are not empty to start and are not
clean cherry-picks of any upstream commit, but which become empty
after rebasing (because they contain a subset of already upstream
changes):

drop
The commit will be dropped. This is the default behavior.

keep
The commit will be kept. This option is implied when --exec
is specified unless -i/--interactive is also specified.

stop, ask
The rebase will halt when the commit is applied, allowing you
to choose whether to drop it, edit files more, or just commit
the empty changes. This option is implied when
-i/--interactive is specified. ask is a deprecated synonym
of stop.

Note that commits which start empty are kept (unless
--no-keep-empty is specified), and commits which are clean
cherry-picks (as determined by git log --cherry-mark ...) are
detected and dropped as a preliminary step (unless
--reapply-cherry-picks or --keep-base is passed).

See also INCOMPATIBLE OPTIONS below.

--no-keep-empty, --keep-empty
Do not keep commits that start empty before the rebase (i.e. that
do not change anything from its parent) in the result. The
default is to keep commits which start empty, since creating such
commits requires passing the --allow-empty override flag to git
commit, signifying that a user is very intentionally creating
such a commit and thus wants to keep it.

Usage of this flag will probably be rare, since you can get rid
of commits that start empty by just firing up an interactive
rebase and removing the lines corresponding to the commits you
don't want. This flag exists as a convenient shortcut, such as
for cases where external tools generate many empty commits and
you want them all removed.

For commits which do not start empty but become empty after
rebasing, see the --empty flag.

See also INCOMPATIBLE OPTIONS below.

--reapply-cherry-picks, --no-reapply-cherry-picks
Reapply all clean cherry-picks of any upstream commit instead of
preemptively dropping them. (If these commits then become empty
after rebasing, because they contain a subset of already upstream
changes, the behavior towards them is controlled by the --empty
flag.)

In the absence of --keep-base (or if --no-reapply-cherry-picks is
given), these commits will be automatically dropped. Because this
necessitates reading all upstream commits, this can be expensive
in repositories with a large number of upstream commits that need
to be read. When using the merge backend, warnings will be issued
for each dropped commit (unless --quiet is given). Advice will
also be issued unless advice.skippedCherryPicks is set to false
(see git-config(1)).

--reapply-cherry-picks allows rebase to forgo reading all
upstream commits, potentially improving performance.

See also INCOMPATIBLE OPTIONS below.

--allow-empty-message
No-op. Rebasing commits with an empty message used to fail and
this option would override that behavior, allowing commits with
empty messages to be rebased. Now commits with an empty message
do not cause rebasing to halt.

See also INCOMPATIBLE OPTIONS below.

-m, --merge
Using merging strategies to rebase (default).

Note that a rebase merge works by replaying each commit from the
working branch on top of the <upstream> branch. Because of this,
when a merge conflict happens, the side reported as ours is the
so-far rebased series, starting with <upstream>, and theirs is
the working branch. In other words, the sides are swapped.

See also INCOMPATIBLE OPTIONS below.

-s <strategy>, --strategy=<strategy>
Use the given merge strategy, instead of the default ort. This
implies --merge.

Because git rebase replays each commit from the working branch on
top of the <upstream> branch using the given strategy, using the
ours strategy simply empties all patches from the <branch>, which
makes little sense.

See also INCOMPATIBLE OPTIONS below.

-X <strategy-option>, --strategy-option=<strategy-option>
Pass the <strategy-option> through to the merge strategy. This
implies --merge and, if no strategy has been specified, -s ort.
Note the reversal of ours and theirs as noted above for the -m
option.

See also INCOMPATIBLE OPTIONS below.

--rerere-autoupdate, --no-rerere-autoupdate
After the rerere mechanism reuses a recorded resolution on the
current conflict to update the files in the working tree, allow
it to also update the index with the result of resolution.
--no-rerere-autoupdate is a good way to double-check what rerere
did and catch potential mismerges, before committing the result
to the index with a separate git add.

-S[<keyid>], --gpg-sign[=<keyid>], --no-gpg-sign
GPG-sign commits. The keyid argument is optional and defaults to
the committer identity; if specified, it must be stuck to the
option without a space. --no-gpg-sign is useful to countermand
both commit.gpgSign configuration variable, and earlier
--gpg-sign.

-q, --quiet
Be quiet. Implies --no-stat.

-v, --verbose
Be verbose. Implies --stat.

--stat
Show a diffstat of what changed upstream since the last rebase.
The diffstat is also controlled by the configuration option
rebase.stat.

-n, --no-stat
Do not show a diffstat as part of the rebase process.

--no-verify
This option bypasses the pre-rebase hook. See also githooks(5).

--verify
Allows the pre-rebase hook to run, which is the default. This
option can be used to override --no-verify. See also githooks(5).

-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.
Implies --apply.

See also INCOMPATIBLE OPTIONS below.

--no-ff, --force-rebase, -f
Individually replay all rebased commits instead of
fast-forwarding over the unchanged ones. This ensures that the
entire history of the rebased branch is composed of new commits.

You may find this helpful after reverting a topic branch merge,
as this option recreates the topic branch with fresh commits so
it can be remerged successfully without needing to "revert the
reversion" (see the revert-a-faulty-merge How-To[1] for details).

--fork-point, --no-fork-point
Use reflog to find a better common ancestor between <upstream>
and <branch> when calculating which commits have been introduced
by <branch>.

When --fork-point is active, fork_point will be used instead of
<upstream> to calculate the set of commits to rebase, where
fork_point is the result of git merge-base --fork-point
<upstream> <branch> command (see git-merge-base(1)). If
fork_point ends up being empty, the <upstream> will be used as a
fallback.

If <upstream> or --keep-base is given on the command line, then
the default is --no-fork-point, otherwise the default is
--fork-point. See also rebase.forkpoint in git-config(1).

If your branch was based on <upstream> but <upstream> was rewound
and your branch contains commits which were dropped, this option
can be used with --keep-base in order to drop those commits from
your branch.

See also INCOMPATIBLE OPTIONS below.

--ignore-whitespace
Ignore whitespace differences when trying to reconcile
differences. Currently, each backend implements an approximation
of this behavior:

apply backend
When applying a patch, ignore changes in whitespace in
context lines. Unfortunately, this means that if the "old"
lines being replaced by the patch differ only in whitespace
from the existing file, you will get a merge conflict instead
of a successful patch application.

merge backend
Treat lines with only whitespace changes as unchanged when
merging. Unfortunately, this means that any patch hunks that
were intended to modify whitespace and nothing else will be
dropped, even if the other side had no changes that
conflicted.

--whitespace=<option>
This flag is passed to the git apply program (see git-apply(1))
that applies the patch. Implies --apply.

See also INCOMPATIBLE OPTIONS below.

--committer-date-is-author-date
Instead of using the current time as the committer date, use the
author date of the commit being rebased as the committer date.
This option implies --force-rebase.

--ignore-date, --reset-author-date
Instead of using the author date of the original commit, use the
current time as the author date of the rebased commit. This
option implies --force-rebase.

See also INCOMPATIBLE OPTIONS below.

--signoff
Add a Signed-off-by trailer to all the rebased commits. Note that
if --interactive is given then only commits marked to be picked,
edited or reworded will have the trailer added.

See also INCOMPATIBLE OPTIONS below.

-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).

The commit list format can be changed by setting the
configuration option rebase.instructionFormat. A customized
instruction format will automatically have the commit hash
prepended to the format.

See also INCOMPATIBLE OPTIONS below.

-r, --rebase-merges[=(rebase-cousins|no-rebase-cousins)],
--no-rebase-merges
By default, a rebase will simply drop merge commits from the todo
list, and put the rebased commits into a single, linear branch.
With --rebase-merges, the rebase will instead try to preserve the
branching structure within the commits that are to be rebased, by
recreating the merge commits. Any resolved merge conflicts or
manual amendments in these merge commits will have to be
resolved/re-applied manually. --no-rebase-merges can be used to
countermand both the rebase.rebaseMerges config option and a
previous --rebase-merges.

When rebasing merges, there are two modes: rebase-cousins and
no-rebase-cousins. If the mode is not specified, it defaults to
no-rebase-cousins. In no-rebase-cousins mode, commits which do
not have <upstream> as direct ancestor will keep their original
branch point, i.e. commits that would be excluded by git-log(1)'s
--ancestry-path option will keep their original ancestry by
default. In rebase-cousins mode, such commits are instead rebased
onto <upstream> (or <onto>, if specified).

It is currently only possible to recreate the merge commits using
the ort merge strategy; different merge strategies can be used
only via explicit exec git merge -s <strategy> [...] commands.

See also REBASING MERGES and INCOMPATIBLE OPTIONS below.

-x <cmd>, --exec <cmd>
Append "exec <cmd>" after each line creating a commit in the
final history. <cmd> will be interpreted as one or more shell
commands. Any command that fails will interrupt the rebase, with
exit code 1.

You may execute several commands by either using one instance of
--exec with several commands:

git rebase -i --exec "cmd1 && cmd2 && ..."

or by giving more than one --exec:

git rebase -i --exec "cmd1" --exec "cmd2" --exec ...

If --autosquash is used, exec lines will not be appended for the
intermediate commits, and will only appear at the end of each
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.

See also INCOMPATIBLE OPTIONS below.

--autosquash, --no-autosquash
Automatically squash commits with specially formatted messages
into previous commits being rebased. If a commit message starts
with "squash! ", "fixup! " or "amend! ", the remainder of the
subject line is taken as a commit specifier, which matches a
previous commit if it matches the subject line or the hash of
that commit. If no commit matches fully, matches of the specifier
with the start of commit subjects are considered.

In the rebase todo list, the actions of squash, fixup and amend
commits are changed from pick to squash, fixup or fixup -C,
respectively, and they are moved right after the commit they
modify. The --interactive option can be used to review and edit
the todo list before proceeding.

The recommended way to create commits with squash markers is by
using the --squash, --fixup, --fixup=amend: or --fixup=reword:
options of git-commit(1), which take the target commit as an
argument and automatically fill in the subject line of the new
commit from that.

Setting configuration variable rebase.autoSquash to true enables
auto-squashing by default for interactive rebase. The
--no-autosquash option can be used to override that 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).

This option applies once a rebase is started. It is preserved for
the whole rebase based on, in order, the command line option
provided to the initial git rebase, the
rebase.rescheduleFailedExec configuration (see git-config(1) or
"CONFIGURATION" below), or it defaults to false.

Recording this option for the whole rebase is a convenience
feature. Otherwise an explicit --no-reschedule-failed-exec at the
start would be overridden by the presence of a
rebase.rescheduleFailedExec=true configuration when git rebase
--continue is invoked. Currently, you cannot pass
--[no-]reschedule-failed-exec to git rebase --continue.

--update-refs, --no-update-refs
Automatically force-update any branches that point to commits
that are being rebased. Any branches that are checked out in a
worktree are not updated in this way.

If the configuration variable rebase.updateRefs is set, then this
option can be used to override and disable this setting.

See also INCOMPATIBLE OPTIONS below.

INCOMPATIBLE OPTIONS

The following options:

+o --apply

+o --whitespace

+o -C

are incompatible with the following options:

+o --merge

+o --strategy

+o --strategy-option

+o --autosquash

+o --rebase-merges

+o --interactive

+o --exec

+o --no-keep-empty

+o --empty=

+o --[no-]reapply-cherry-picks when used without --keep-base

+o --update-refs

+o --root when used without --onto

In addition, the following pairs of options are incompatible:

+o --keep-base and --onto

+o --keep-base and --root

+o --fork-point and --root

BEHAVIORAL DIFFERENCES

git rebase has two primary backends: apply and merge. (The apply
backend used to be 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 by default
(though with -i they are marked as empty in the todo list editor, or
they can be dropped automatically with --no-keep-empty).

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|stop) 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 offset, 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 or zdiff3, 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. Both have called the post-checkout hook,
though the merge backend has squelched its output. Further, both
backends only call the post-checkout hook with the starting point
commit of the rebase, not the intermediate commits nor the final
commit. In each case, the calling of these hooks was by accident of
implementation rather than by design (both backends were originally
implemented as shell scripts and happened to invoke other commands
like git checkout or git commit that would call the hooks). Both
backends should have the same behavior, though it is not entirely
clear which, if any, is correct. We will likely make rebase stop
calling either of these hooks in the future.

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:

+o 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".

+o 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.

+o State directories: The two backends keep their state in different
directories under .git/

MERGE STRATEGIES

The merge mechanism (git merge and git pull commands) allows the
backend merge strategies to be chosen with -s option. Some strategies
can also take their own options, which can be passed by giving
-X<option> arguments to git merge and/or git pull.

ort
This is the default merge strategy when pulling or merging one
branch. This strategy can only resolve two heads using a 3-way
merge algorithm. When there is more than one common ancestor 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 mismerges by tests done on actual merge
commits taken from Linux 2.6 kernel development history.
Additionally this strategy can detect and handle merges involving
renames. It does not make use of detected copies. The name for
this algorithm is an acronym ("Ostensibly Recursive's Twin") and
came from the fact that it was written as a replacement for the
previous default algorithm, recursive.

The ort strategy can take the following options:

ours
This option forces conflicting hunks to be auto-resolved
cleanly by favoring our version. Changes from the other tree
that do not conflict with our side are reflected in the merge
result. For a binary file, the entire contents are taken from
our side.

This should not be confused with the ours merge strategy,
which does not even look at what the other tree contains at
all. It discards everything the other tree did, declaring our
history contains all that happened in it.

theirs
This is the opposite of ours; note that, unlike ours, there
is no theirs merge strategy to confuse this merge option
with.

ignore-space-change, ignore-all-space, ignore-space-at-eol,
ignore-cr-at-eol
Treats lines with the indicated type of whitespace change as
unchanged for the sake of a three-way merge. Whitespace
changes mixed with other changes to a line are not ignored.
See also git-diff(1) -b, -w, --ignore-space-at-eol, and
--ignore-cr-at-eol.

+o If their version only introduces whitespace changes to a
line, our version is used;

+o If our version introduces whitespace changes but their
version includes a substantial change, their version is
used;

+o Otherwise, the merge proceeds in the usual way.

renormalize
This runs a virtual check-out and check-in of all three
stages of a file when resolving a three-way merge. This
option is meant to be used when merging branches with
different clean filters or end-of-line normalization rules.
See "Merging branches with differing checkin/checkout
attributes" in gitattributes(5) for details.

no-renormalize
Disables the renormalize option. This overrides the
merge.renormalize configuration variable.

find-renames[=<n>]
Turn on rename detection, optionally setting the similarity
threshold. This is the default. This overrides the
merge.renames configuration variable. See also git-diff(1)
--find-renames.

rename-threshold=<n>
Deprecated synonym for find-renames=<n>.

subtree[=<path>]
This option is a more advanced form of subtree strategy,
where the strategy makes a guess on how two trees must be
shifted to match with each other when merging. Instead, the
specified path is prefixed (or stripped from the beginning)
to make the shape of two trees to match.

recursive
This can only resolve two heads using a 3-way merge algorithm.
When there is more than one common ancestor 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
mismerges by tests done on actual merge commits taken from Linux
2.6 kernel development history. Additionally this can detect and
handle merges involving renames. It does not make use of detected
copies. This was the default strategy for resolving two heads
from Git v0.99.9k until v2.33.0.

The recursive strategy takes the same options as ort. However,
there are three additional options that ort ignores (not
documented above) that are potentially useful with the recursive
strategy:

patience
Deprecated synonym for diff-algorithm=patience.

diff-algorithm=[patience|minimal|histogram|myers]
Use a different diff algorithm while merging, which can help
avoid mismerges that occur due to unimportant matching lines
(such as braces from distinct functions). See also git-
diff(1) --diff-algorithm. Note that ort specifically uses
diff-algorithm=histogram, while recursive defaults to the
diff.algorithm config setting.

no-renames
Turn off rename detection. This overrides the merge.renames
configuration variable. See also git-diff(1) --no-renames.

resolve
This can only resolve two heads (i.e. the current branch and
another branch you pulled from) using a 3-way merge algorithm. It
tries to carefully detect criss-cross merge ambiguities. It does
not handle renames.

octopus
This resolves cases with more than two heads, but refuses to do a
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
branch.

ours
This resolves any number of heads, but the resulting tree of the
merge is always that of the current branch head, effectively
ignoring all changes from all other branches. It is meant to be
used to supersede old development history of side branches. Note
that this is different from the -Xours option to the recursive
merge strategy.

subtree
This is a modified ort strategy. When merging trees A and B, if B
corresponds to a subtree of A, B is first adjusted to match the
tree structure of A, instead of reading the trees at the same
level. This adjustment is also done to the common ancestor tree.

With the strategies that use 3-way merge (including the default,
ort), if a change is made on both branches, but later reverted on one
of the branches, that change will be present in the merged result;
some people find this behavior confusing. It occurs because only the
heads and the merge base are considered when performing a merge, not
the individual commits. The merge algorithm therefore considers the
reverted change as no change at all, and substitutes the changed
version instead.

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 rebase 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 first
commit's message with those identified by "squash" commands, omitting
the messages of commits identified by "fixup" commands, unless "fixup
-c" is used. In that case the suggested commit message is only the
message of the "fixup -c" commit, and an editor is opened allowing
you to edit the message. The contents (patch) of the "fixup -c"
commit are still incorporated into the folded commit. If there is
more than one "fixup -c" commit, the message from the final one is
used. You can also use "fixup -C" to get the same behavior as "fixup
-c" except without opening an editor.

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 default one,
usually /bin/sh), 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:

+o 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.

+o Mark the commit you want to split with the action "edit".

+o 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.

+o 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.

+o Commit the now-current index with whatever commit message is
appropriate now.

+o Repeat the last two steps until your working tree is clean.

+o 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 filter-repo[2].

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 (unless
--reapply-cherry-picks is given). 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:

+o With the subsystem reflog: after git fetch, the old tip of
subsystem is at subsystem@{1}. Subsequent fetches will increase
the number. (See git-reflog(1).)

+o 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.

By default, the merge command will use the ort merge strategy for
regular merges, and octopus for octopus merges. One can specify a
default strategy for all merges using the --strategy argument when
invoking rebase, or can override specific merges in the interactive
list of commands by using an exec command to call git merge
explicitly with a --strategy argument. Note that when calling git
merge explicitly like this, you can make use of the fact that the
labels are worktree-local refs (the ref refs/rewritten/onto would
correspond to the label onto, for example) in order to refer to the
branches you want to merge.

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

CONFIGURATION

Everything below this line in this section is selectively included
from the git-config(1) documentation. The content is the same as
what's found there:

rebase.backend
Default backend to use for rebasing. Possible choices are apply
or merge. In the future, if the merge backend gains all remaining
capabilities of the apply backend, this setting may become
unused.

rebase.stat
Whether to show a diffstat of what changed upstream since the
last rebase. False by default.

rebase.autoSquash
If set to true, enable the --autosquash option of git-rebase(1)
by default for interactive mode. This can be overridden with the
--no-autosquash option.

rebase.autoStash
When set to true, 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. This
option can be overridden by the --no-autostash and --autostash
options of git-rebase(1). Defaults to false.

rebase.updateRefs
If set to true enable --update-refs option by default.

rebase.missingCommitsCheck
If set to "warn", git rebase -i will print a warning if some
commits are removed (e.g. a line was deleted), however the rebase
will still proceed. If set to "error", it will print the previous
warning and stop the rebase, git rebase --edit-todo can then be
used to correct the error. If set to "ignore", no checking is
done. To drop a commit without warning or error, use the drop
command in the todo list. Defaults to "ignore".

rebase.instructionFormat
A format string, as specified in git-log(1), to be used for the
todo list during an interactive rebase. The format will
automatically have the commit hash prepended to the format.

rebase.abbreviateCommands
If set to true, git rebase will use abbreviated command names in
the todo list resulting in something like this:

p deadbee The oneline of the commit
p fa1afe1 The oneline of the next commit
...

instead of:

pick deadbee The oneline of the commit
pick fa1afe1 The oneline of the next commit
...

Defaults to false.

rebase.rescheduleFailedExec
Automatically reschedule exec commands that failed. This only
makes sense in interactive mode (or when an --exec option was
provided). This is the same as specifying the
--reschedule-failed-exec option.

rebase.forkPoint
If set to false set --no-fork-point option by default.

rebase.rebaseMerges
Whether and how to set the --rebase-merges option by default. Can
be rebase-cousins, no-rebase-cousins, or a boolean. Setting to
true or to no-rebase-cousins is equivalent to
--rebase-merges=no-rebase-cousins, setting to rebase-cousins is
equivalent to --rebase-merges=rebase-cousins, and setting to
false is equivalent to --no-rebase-merges. Passing
--rebase-merges on the command line, with or without an argument,
overrides any rebase.rebaseMerges configuration.

rebase.maxLabelLength
When generating label names from commit subjects, truncate the
names to this length. By default, the names are truncated to a
little less than NAME_MAX (to allow e.g. .lock files to be
written for the corresponding loose refs).

sequence.editor
Text editor used by git rebase -i for editing the rebase
instruction file. The value is meant to be interpreted by the
shell when it is used. It can be overridden by the
GIT_SEQUENCE_EDITOR environment variable. When not configured,
the default commit message editor is used instead.

GIT

Part of the git(1) suite

NOTES

1. revert-a-faulty-merge How-To
git-htmldocs/howto/revert-a-faulty-merge.html

2. filter-repo
https://github.com/newren/git-filter-repo

Git 2.48.1 2025-01-13 GIT-REBASE(1)