Documentation / git-rebase.txton commit wt-status.h: drop stdio.h include (7a06fb0)
   1git-rebase(1)
   2=============
   3
   4NAME
   5----
   6git-rebase - Reapply commits on top of another base tip
   7
   8SYNOPSIS
   9--------
  10[verse]
  11'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
  12        [<upstream> [<branch>]]
  13'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
  14        --root [<branch>]
  15'git rebase' --continue | --skip | --abort | --quit | --edit-todo | --show-current-patch
  16
  17DESCRIPTION
  18-----------
  19If <branch> is specified, 'git rebase' will perform an automatic
  20`git checkout <branch>` before doing anything else.  Otherwise
  21it remains on the current branch.
  22
  23If <upstream> is not specified, the upstream configured in
  24branch.<name>.remote and branch.<name>.merge options will be used (see
  25linkgit:git-config[1] for details) and the `--fork-point` option is
  26assumed.  If you are currently not on any branch or if the current
  27branch does not have a configured upstream, the rebase will abort.
  28
  29All changes made by commits in the current branch but that are not
  30in <upstream> are saved to a temporary area.  This is the same set
  31of commits that would be shown by `git log <upstream>..HEAD`; or by
  32`git log 'fork_point'..HEAD`, if `--fork-point` is active (see the
  33description on `--fork-point` below); or by `git log HEAD`, if the
  34`--root` option is specified.
  35
  36The current branch is reset to <upstream>, or <newbase> if the
  37--onto option was supplied.  This has the exact same effect as
  38`git reset --hard <upstream>` (or <newbase>).  ORIG_HEAD is set
  39to point at the tip of the branch before the reset.
  40
  41The commits that were previously saved into the temporary area are
  42then reapplied to the current branch, one by one, in order. Note that
  43any commits in HEAD which introduce the same textual changes as a commit
  44in HEAD..<upstream> are omitted (i.e., a patch already accepted upstream
  45with a different commit message or timestamp will be skipped).
  46
  47It is possible that a merge failure will prevent this process from being
  48completely automatic.  You will have to resolve any such merge failure
  49and run `git rebase --continue`.  Another option is to bypass the commit
  50that caused the merge failure with `git rebase --skip`.  To check out the
  51original <branch> and remove the .git/rebase-apply working files, use the
  52command `git rebase --abort` instead.
  53
  54Assume the following history exists and the current branch is "topic":
  55
  56------------
  57          A---B---C topic
  58         /
  59    D---E---F---G master
  60------------
  61
  62From this point, the result of either of the following commands:
  63
  64
  65    git rebase master
  66    git rebase master topic
  67
  68would be:
  69
  70------------
  71                  A'--B'--C' topic
  72                 /
  73    D---E---F---G master
  74------------
  75
  76*NOTE:* The latter form is just a short-hand of `git checkout topic`
  77followed by `git rebase master`. When rebase exits `topic` will
  78remain the checked-out branch.
  79
  80If the upstream branch already contains a change you have made (e.g.,
  81because you mailed a patch which was applied upstream), then that commit
  82will be skipped. For example, running `git rebase master` on the
  83following history (in which `A'` and `A` introduce the same set of changes,
  84but have different committer information):
  85
  86------------
  87          A---B---C topic
  88         /
  89    D---E---A'---F master
  90------------
  91
  92will result in:
  93
  94------------
  95                   B'---C' topic
  96                  /
  97    D---E---A'---F master
  98------------
  99
 100Here is how you would transplant a topic branch based on one
 101branch to another, to pretend that you forked the topic branch
 102from the latter branch, using `rebase --onto`.
 103
 104First let's assume your 'topic' is based on branch 'next'.
 105For example, a feature developed in 'topic' depends on some
 106functionality which is found in 'next'.
 107
 108------------
 109    o---o---o---o---o  master
 110         \
 111          o---o---o---o---o  next
 112                           \
 113                            o---o---o  topic
 114------------
 115
 116We want to make 'topic' forked from branch 'master'; for example,
 117because the functionality on which 'topic' depends was merged into the
 118more stable 'master' branch. We want our tree to look like this:
 119
 120------------
 121    o---o---o---o---o  master
 122        |            \
 123        |             o'--o'--o'  topic
 124         \
 125          o---o---o---o---o  next
 126------------
 127
 128We can get this using the following command:
 129
 130    git rebase --onto master next topic
 131
 132
 133Another example of --onto option is to rebase part of a
 134branch.  If we have the following situation:
 135
 136------------
 137                            H---I---J topicB
 138                           /
 139                  E---F---G  topicA
 140                 /
 141    A---B---C---D  master
 142------------
 143
 144then the command
 145
 146    git rebase --onto master topicA topicB
 147
 148would result in:
 149
 150------------
 151                 H'--I'--J'  topicB
 152                /
 153                | E---F---G  topicA
 154                |/
 155    A---B---C---D  master
 156------------
 157
 158This is useful when topicB does not depend on topicA.
 159
 160A range of commits could also be removed with rebase.  If we have
 161the following situation:
 162
 163------------
 164    E---F---G---H---I---J  topicA
 165------------
 166
 167then the command
 168
 169    git rebase --onto topicA~5 topicA~3 topicA
 170
 171would result in the removal of commits F and G:
 172
 173------------
 174    E---H'---I'---J'  topicA
 175------------
 176
 177This is useful if F and G were flawed in some way, or should not be
 178part of topicA.  Note that the argument to --onto and the <upstream>
 179parameter can be any valid commit-ish.
 180
 181In case of conflict, 'git rebase' will stop at the first problematic commit
 182and leave conflict markers in the tree.  You can use 'git diff' to locate
 183the markers (<<<<<<) and make edits to resolve the conflict.  For each
 184file you edit, you need to tell Git that the conflict has been resolved,
 185typically this would be done with
 186
 187
 188    git add <filename>
 189
 190
 191After resolving the conflict manually and updating the index with the
 192desired resolution, you can continue the rebasing process with
 193
 194
 195    git rebase --continue
 196
 197
 198Alternatively, you can undo the 'git rebase' with
 199
 200
 201    git rebase --abort
 202
 203CONFIGURATION
 204-------------
 205
 206include::config/rebase.txt[]
 207
 208OPTIONS
 209-------
 210--onto <newbase>::
 211        Starting point at which to create the new commits. If the
 212        --onto option is not specified, the starting point is
 213        <upstream>.  May be any valid commit, and not just an
 214        existing branch name.
 215+
 216As a special case, you may use "A\...B" as a shortcut for the
 217merge base of A and B if there is exactly one merge base. You can
 218leave out at most one of A and B, in which case it defaults to HEAD.
 219
 220<upstream>::
 221        Upstream branch to compare against.  May be any valid commit,
 222        not just an existing branch name. Defaults to the configured
 223        upstream for the current branch.
 224
 225<branch>::
 226        Working branch; defaults to HEAD.
 227
 228--continue::
 229        Restart the rebasing process after having resolved a merge conflict.
 230
 231--abort::
 232        Abort the rebase operation and reset HEAD to the original
 233        branch. If <branch> was provided when the rebase operation was
 234        started, then HEAD will be reset to <branch>. Otherwise HEAD
 235        will be reset to where it was when the rebase operation was
 236        started.
 237
 238--quit::
 239        Abort the rebase operation but HEAD is not reset back to the
 240        original branch. The index and working tree are also left
 241        unchanged as a result.
 242
 243--keep-empty::
 244        Keep the commits that do not change anything from its
 245        parents in the result.
 246+
 247See also INCOMPATIBLE OPTIONS below.
 248
 249--allow-empty-message::
 250        By default, rebasing commits with an empty message will fail.
 251        This option overrides that behavior, allowing commits with empty
 252        messages to be rebased.
 253+
 254See also INCOMPATIBLE OPTIONS below.
 255
 256--skip::
 257        Restart the rebasing process by skipping the current patch.
 258
 259--edit-todo::
 260        Edit the todo list during an interactive rebase.
 261
 262--show-current-patch::
 263        Show the current patch in an interactive rebase or when rebase
 264        is stopped because of conflicts. This is the equivalent of
 265        `git show REBASE_HEAD`.
 266
 267-m::
 268--merge::
 269        Use merging strategies to rebase.  When the recursive (default) merge
 270        strategy is used, this allows rebase to be aware of renames on the
 271        upstream side.
 272+
 273Note that a rebase merge works by replaying each commit from the working
 274branch on top of the <upstream> branch.  Because of this, when a merge
 275conflict happens, the side reported as 'ours' is the so-far rebased
 276series, starting with <upstream>, and 'theirs' is the working branch.  In
 277other words, the sides are swapped.
 278+
 279See also INCOMPATIBLE OPTIONS below.
 280
 281-s <strategy>::
 282--strategy=<strategy>::
 283        Use the given merge strategy.
 284        If there is no `-s` option 'git merge-recursive' is used
 285        instead.  This implies --merge.
 286+
 287Because 'git rebase' replays each commit from the working branch
 288on top of the <upstream> branch using the given strategy, using
 289the 'ours' strategy simply empties all patches from the <branch>,
 290which makes little sense.
 291+
 292See also INCOMPATIBLE OPTIONS below.
 293
 294-X <strategy-option>::
 295--strategy-option=<strategy-option>::
 296        Pass the <strategy-option> through to the merge strategy.
 297        This implies `--merge` and, if no strategy has been
 298        specified, `-s recursive`.  Note the reversal of 'ours' and
 299        'theirs' as noted above for the `-m` option.
 300+
 301See also INCOMPATIBLE OPTIONS below.
 302
 303--rerere-autoupdate::
 304--no-rerere-autoupdate::
 305        Allow the rerere mechanism to update the index with the
 306        result of auto-conflict resolution if possible.
 307
 308-S[<keyid>]::
 309--gpg-sign[=<keyid>]::
 310        GPG-sign commits. The `keyid` argument is optional and
 311        defaults to the committer identity; if specified, it must be
 312        stuck to the option without a space.
 313
 314-q::
 315--quiet::
 316        Be quiet. Implies --no-stat.
 317
 318-v::
 319--verbose::
 320        Be verbose. Implies --stat.
 321
 322--stat::
 323        Show a diffstat of what changed upstream since the last rebase. The
 324        diffstat is also controlled by the configuration option rebase.stat.
 325
 326-n::
 327--no-stat::
 328        Do not show a diffstat as part of the rebase process.
 329
 330--no-verify::
 331        This option bypasses the pre-rebase hook.  See also linkgit:githooks[5].
 332
 333--verify::
 334        Allows the pre-rebase hook to run, which is the default.  This option can
 335        be used to override --no-verify.  See also linkgit:githooks[5].
 336
 337-C<n>::
 338        Ensure at least <n> lines of surrounding context match before
 339        and after each change.  When fewer lines of surrounding
 340        context exist they all must match.  By default no context is
 341        ever ignored.
 342+
 343See also INCOMPATIBLE OPTIONS below.
 344
 345--no-ff::
 346--force-rebase::
 347-f::
 348        Individually replay all rebased commits instead of fast-forwarding
 349        over the unchanged ones.  This ensures that the entire history of
 350        the rebased branch is composed of new commits.
 351+
 352You may find this helpful after reverting a topic branch merge, as this option
 353recreates the topic branch with fresh commits so it can be remerged
 354successfully without needing to "revert the reversion" (see the
 355link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for
 356details).
 357
 358--fork-point::
 359--no-fork-point::
 360        Use reflog to find a better common ancestor between <upstream>
 361        and <branch> when calculating which commits have been
 362        introduced by <branch>.
 363+
 364When --fork-point is active, 'fork_point' will be used instead of
 365<upstream> to calculate the set of commits to rebase, where
 366'fork_point' is the result of `git merge-base --fork-point <upstream>
 367<branch>` command (see linkgit:git-merge-base[1]).  If 'fork_point'
 368ends up being empty, the <upstream> will be used as a fallback.
 369+
 370If either <upstream> or --root is given on the command line, then the
 371default is `--no-fork-point`, otherwise the default is `--fork-point`.
 372
 373--ignore-whitespace::
 374--whitespace=<option>::
 375        These flag are passed to the 'git apply' program
 376        (see linkgit:git-apply[1]) that applies the patch.
 377+
 378See also INCOMPATIBLE OPTIONS below.
 379
 380--committer-date-is-author-date::
 381--ignore-date::
 382        These flags are passed to 'git am' to easily change the dates
 383        of the rebased commits (see linkgit:git-am[1]).
 384+
 385See also INCOMPATIBLE OPTIONS below.
 386
 387--signoff::
 388        Add a Signed-off-by: trailer to all the rebased commits. Note
 389        that if `--interactive` is given then only commits marked to be
 390        picked, edited or reworded will have the trailer added.
 391+
 392See also INCOMPATIBLE OPTIONS below.
 393
 394-i::
 395--interactive::
 396        Make a list of the commits which are about to be rebased.  Let the
 397        user edit that list before rebasing.  This mode can also be used to
 398        split commits (see SPLITTING COMMITS below).
 399+
 400The commit list format can be changed by setting the configuration option
 401rebase.instructionFormat.  A customized instruction format will automatically
 402have the long commit hash prepended to the format.
 403+
 404See also INCOMPATIBLE OPTIONS below.
 405
 406-r::
 407--rebase-merges[=(rebase-cousins|no-rebase-cousins)]::
 408        By default, a rebase will simply drop merge commits from the todo
 409        list, and put the rebased commits into a single, linear branch.
 410        With `--rebase-merges`, the rebase will instead try to preserve
 411        the branching structure within the commits that are to be rebased,
 412        by recreating the merge commits. Any resolved merge conflicts or
 413        manual amendments in these merge commits will have to be
 414        resolved/re-applied manually.
 415+
 416By default, or when `no-rebase-cousins` was specified, commits which do not
 417have `<upstream>` as direct ancestor will keep their original branch point,
 418i.e. commits that would be excluded by linkgit:git-log[1]'s
 419`--ancestry-path` option will keep their original ancestry by default. If
 420the `rebase-cousins` mode is turned on, such commits are instead rebased
 421onto `<upstream>` (or `<onto>`, if specified).
 422+
 423The `--rebase-merges` mode is similar in spirit to the deprecated
 424`--preserve-merges`, but in contrast to that option works well in interactive
 425rebases: commits can be reordered, inserted and dropped at will.
 426+
 427It is currently only possible to recreate the merge commits using the
 428`recursive` merge strategy; Different merge strategies can be used only via
 429explicit `exec git merge -s <strategy> [...]` commands.
 430+
 431See also REBASING MERGES and INCOMPATIBLE OPTIONS below.
 432
 433-p::
 434--preserve-merges::
 435        [DEPRECATED: use `--rebase-merges` instead] Recreate merge commits
 436        instead of flattening the history by replaying commits a merge commit
 437        introduces. Merge conflict resolutions or manual amendments to merge
 438        commits are not preserved.
 439+
 440This uses the `--interactive` machinery internally, but combining it
 441with the `--interactive` option explicitly is generally not a good
 442idea unless you know what you are doing (see BUGS below).
 443+
 444See also INCOMPATIBLE OPTIONS below.
 445
 446-x <cmd>::
 447--exec <cmd>::
 448        Append "exec <cmd>" after each line creating a commit in the
 449        final history. <cmd> will be interpreted as one or more shell
 450        commands. Any command that fails will interrupt the rebase,
 451        with exit code 1.
 452+
 453You may execute several commands by either using one instance of `--exec`
 454with several commands:
 455+
 456        git rebase -i --exec "cmd1 && cmd2 && ..."
 457+
 458or by giving more than one `--exec`:
 459+
 460        git rebase -i --exec "cmd1" --exec "cmd2" --exec ...
 461+
 462If `--autosquash` is used, "exec" lines will not be appended for
 463the intermediate commits, and will only appear at the end of each
 464squash/fixup series.
 465+
 466This uses the `--interactive` machinery internally, but it can be run
 467without an explicit `--interactive`.
 468+
 469See also INCOMPATIBLE OPTIONS below.
 470
 471--root::
 472        Rebase all commits reachable from <branch>, instead of
 473        limiting them with an <upstream>.  This allows you to rebase
 474        the root commit(s) on a branch.  When used with --onto, it
 475        will skip changes already contained in <newbase> (instead of
 476        <upstream>) whereas without --onto it will operate on every change.
 477        When used together with both --onto and --preserve-merges,
 478        'all' root commits will be rewritten to have <newbase> as parent
 479        instead.
 480+
 481See also INCOMPATIBLE OPTIONS below.
 482
 483--autosquash::
 484--no-autosquash::
 485        When the commit log message begins with "squash! ..." (or
 486        "fixup! ..."), and there is already a commit in the todo list that
 487        matches the same `...`, automatically modify the todo list of rebase
 488        -i so that the commit marked for squashing comes right after the
 489        commit to be modified, and change the action of the moved commit
 490        from `pick` to `squash` (or `fixup`).  A commit matches the `...` if
 491        the commit subject matches, or if the `...` refers to the commit's
 492        hash. As a fall-back, partial matches of the commit subject work,
 493        too.  The recommended way to create fixup/squash commits is by using
 494        the `--fixup`/`--squash` options of linkgit:git-commit[1].
 495+
 496If the `--autosquash` option is enabled by default using the
 497configuration variable `rebase.autoSquash`, this option can be
 498used to override and disable this setting.
 499+
 500See also INCOMPATIBLE OPTIONS below.
 501
 502--autostash::
 503--no-autostash::
 504        Automatically create a temporary stash entry before the operation
 505        begins, and apply it after the operation ends.  This means
 506        that you can run rebase on a dirty worktree.  However, use
 507        with care: the final stash application after a successful
 508        rebase might result in non-trivial conflicts.
 509
 510--reschedule-failed-exec::
 511--no-reschedule-failed-exec::
 512        Automatically reschedule `exec` commands that failed. This only makes
 513        sense in interactive mode (or when an `--exec` option was provided).
 514
 515INCOMPATIBLE OPTIONS
 516--------------------
 517
 518The following options:
 519
 520 * --committer-date-is-author-date
 521 * --ignore-date
 522 * --whitespace
 523 * --ignore-whitespace
 524 * -C
 525
 526are incompatible with the following options:
 527
 528 * --merge
 529 * --strategy
 530 * --strategy-option
 531 * --allow-empty-message
 532 * --[no-]autosquash
 533 * --rebase-merges
 534 * --preserve-merges
 535 * --interactive
 536 * --exec
 537 * --keep-empty
 538 * --edit-todo
 539 * --root when used in combination with --onto
 540
 541In addition, the following pairs of options are incompatible:
 542
 543 * --preserve-merges and --interactive
 544 * --preserve-merges and --signoff
 545 * --preserve-merges and --rebase-merges
 546 * --rebase-merges and --strategy
 547 * --rebase-merges and --strategy-option
 548
 549BEHAVIORAL DIFFERENCES
 550-----------------------
 551
 552There are some subtle differences how the backends behave.
 553
 554Empty commits
 555~~~~~~~~~~~~~
 556
 557The am backend drops any "empty" commits, regardless of whether the
 558commit started empty (had no changes relative to its parent to
 559start with) or ended empty (all changes were already applied
 560upstream in other commits).
 561
 562The interactive backend drops commits by default that
 563started empty and halts if it hits a commit that ended up empty.
 564The `--keep-empty` option exists for the interactive backend to allow
 565it to keep commits that started empty.
 566
 567Directory rename detection
 568~~~~~~~~~~~~~~~~~~~~~~~~~~
 569
 570Directory rename heuristics are enabled in the merge and interactive
 571backends.  Due to the lack of accurate tree information, directory
 572rename detection is disabled in the am backend.
 573
 574include::merge-strategies.txt[]
 575
 576NOTES
 577-----
 578
 579You should understand the implications of using 'git rebase' on a
 580repository that you share.  See also RECOVERING FROM UPSTREAM REBASE
 581below.
 582
 583When the git-rebase command is run, it will first execute a "pre-rebase"
 584hook if one exists.  You can use this hook to do sanity checks and
 585reject the rebase if it isn't appropriate.  Please see the template
 586pre-rebase hook script for an example.
 587
 588Upon completion, <branch> will be the current branch.
 589
 590INTERACTIVE MODE
 591----------------
 592
 593Rebasing interactively means that you have a chance to edit the commits
 594which are rebased.  You can reorder the commits, and you can
 595remove them (weeding out bad or otherwise unwanted patches).
 596
 597The interactive mode is meant for this type of workflow:
 598
 5991. have a wonderful idea
 6002. hack on the code
 6013. prepare a series for submission
 6024. submit
 603
 604where point 2. consists of several instances of
 605
 606a) regular use
 607
 608 1. finish something worthy of a commit
 609 2. commit
 610
 611b) independent fixup
 612
 613 1. realize that something does not work
 614 2. fix that
 615 3. commit it
 616
 617Sometimes the thing fixed in b.2. cannot be amended to the not-quite
 618perfect commit it fixes, because that commit is buried deeply in a
 619patch series.  That is exactly what interactive rebase is for: use it
 620after plenty of "a"s and "b"s, by rearranging and editing
 621commits, and squashing multiple commits into one.
 622
 623Start it with the last commit you want to retain as-is:
 624
 625        git rebase -i <after-this-commit>
 626
 627An editor will be fired up with all the commits in your current branch
 628(ignoring merge commits), which come after the given commit.  You can
 629reorder the commits in this list to your heart's content, and you can
 630remove them.  The list looks more or less like this:
 631
 632-------------------------------------------
 633pick deadbee The oneline of this commit
 634pick fa1afe1 The oneline of the next commit
 635...
 636-------------------------------------------
 637
 638The oneline descriptions are purely for your pleasure; 'git rebase' will
 639not look at them but at the commit names ("deadbee" and "fa1afe1" in this
 640example), so do not delete or edit the names.
 641
 642By replacing the command "pick" with the command "edit", you can tell
 643'git rebase' to stop after applying that commit, so that you can edit
 644the files and/or the commit message, amend the commit, and continue
 645rebasing.
 646
 647To interrupt the rebase (just like an "edit" command would do, but without
 648cherry-picking any commit first), use the "break" command.
 649
 650If you just want to edit the commit message for a commit, replace the
 651command "pick" with the command "reword".
 652
 653To drop a commit, replace the command "pick" with "drop", or just
 654delete the matching line.
 655
 656If you want to fold two or more commits into one, replace the command
 657"pick" for the second and subsequent commits with "squash" or "fixup".
 658If the commits had different authors, the folded commit will be
 659attributed to the author of the first commit.  The suggested commit
 660message for the folded commit is the concatenation of the commit
 661messages of the first commit and of those with the "squash" command,
 662but omits the commit messages of commits with the "fixup" command.
 663
 664'git rebase' will stop when "pick" has been replaced with "edit" or
 665when a command fails due to merge errors. When you are done editing
 666and/or resolving conflicts you can continue with `git rebase --continue`.
 667
 668For example, if you want to reorder the last 5 commits, such that what
 669was HEAD~4 becomes the new HEAD. To achieve that, you would call
 670'git rebase' like this:
 671
 672----------------------
 673$ git rebase -i HEAD~5
 674----------------------
 675
 676And move the first patch to the end of the list.
 677
 678You might want to recreate merge commits, e.g. if you have a history
 679like this:
 680
 681------------------
 682           X
 683            \
 684         A---M---B
 685        /
 686---o---O---P---Q
 687------------------
 688
 689Suppose you want to rebase the side branch starting at "A" to "Q". Make
 690sure that the current HEAD is "B", and call
 691
 692-----------------------------
 693$ git rebase -i -r --onto Q O
 694-----------------------------
 695
 696Reordering and editing commits usually creates untested intermediate
 697steps.  You may want to check that your history editing did not break
 698anything by running a test, or at least recompiling at intermediate
 699points in history by using the "exec" command (shortcut "x").  You may
 700do so by creating a todo list like this one:
 701
 702-------------------------------------------
 703pick deadbee Implement feature XXX
 704fixup f1a5c00 Fix to feature XXX
 705exec make
 706pick c0ffeee The oneline of the next commit
 707edit deadbab The oneline of the commit after
 708exec cd subdir; make test
 709...
 710-------------------------------------------
 711
 712The interactive rebase will stop when a command fails (i.e. exits with
 713non-0 status) to give you an opportunity to fix the problem. You can
 714continue with `git rebase --continue`.
 715
 716The "exec" command launches the command in a shell (the one specified
 717in `$SHELL`, or the default shell if `$SHELL` is not set), so you can
 718use shell features (like "cd", ">", ";" ...). The command is run from
 719the root of the working tree.
 720
 721----------------------------------
 722$ git rebase -i --exec "make test"
 723----------------------------------
 724
 725This command lets you check that intermediate commits are compilable.
 726The todo list becomes like that:
 727
 728--------------------
 729pick 5928aea one
 730exec make test
 731pick 04d0fda two
 732exec make test
 733pick ba46169 three
 734exec make test
 735pick f4593f9 four
 736exec make test
 737--------------------
 738
 739SPLITTING COMMITS
 740-----------------
 741
 742In interactive mode, you can mark commits with the action "edit".  However,
 743this does not necessarily mean that 'git rebase' expects the result of this
 744edit to be exactly one commit.  Indeed, you can undo the commit, or you can
 745add other commits.  This can be used to split a commit into two:
 746
 747- Start an interactive rebase with `git rebase -i <commit>^`, where
 748  <commit> is the commit you want to split.  In fact, any commit range
 749  will do, as long as it contains that commit.
 750
 751- Mark the commit you want to split with the action "edit".
 752
 753- When it comes to editing that commit, execute `git reset HEAD^`.  The
 754  effect is that the HEAD is rewound by one, and the index follows suit.
 755  However, the working tree stays the same.
 756
 757- Now add the changes to the index that you want to have in the first
 758  commit.  You can use `git add` (possibly interactively) or
 759  'git gui' (or both) to do that.
 760
 761- Commit the now-current index with whatever commit message is appropriate
 762  now.
 763
 764- Repeat the last two steps until your working tree is clean.
 765
 766- Continue the rebase with `git rebase --continue`.
 767
 768If you are not absolutely sure that the intermediate revisions are
 769consistent (they compile, pass the testsuite, etc.) you should use
 770'git stash' to stash away the not-yet-committed changes
 771after each commit, test, and amend the commit if fixes are necessary.
 772
 773
 774RECOVERING FROM UPSTREAM REBASE
 775-------------------------------
 776
 777Rebasing (or any other form of rewriting) a branch that others have
 778based work on is a bad idea: anyone downstream of it is forced to
 779manually fix their history.  This section explains how to do the fix
 780from the downstream's point of view.  The real fix, however, would be
 781to avoid rebasing the upstream in the first place.
 782
 783To illustrate, suppose you are in a situation where someone develops a
 784'subsystem' branch, and you are working on a 'topic' that is dependent
 785on this 'subsystem'.  You might end up with a history like the
 786following:
 787
 788------------
 789    o---o---o---o---o---o---o---o  master
 790         \
 791          o---o---o---o---o  subsystem
 792                           \
 793                            *---*---*  topic
 794------------
 795
 796If 'subsystem' is rebased against 'master', the following happens:
 797
 798------------
 799    o---o---o---o---o---o---o---o  master
 800         \                       \
 801          o---o---o---o---o       o'--o'--o'--o'--o'  subsystem
 802                           \
 803                            *---*---*  topic
 804------------
 805
 806If you now continue development as usual, and eventually merge 'topic'
 807to 'subsystem', the commits from 'subsystem' will remain duplicated forever:
 808
 809------------
 810    o---o---o---o---o---o---o---o  master
 811         \                       \
 812          o---o---o---o---o       o'--o'--o'--o'--o'--M  subsystem
 813                           \                         /
 814                            *---*---*-..........-*--*  topic
 815------------
 816
 817Such duplicates are generally frowned upon because they clutter up
 818history, making it harder to follow.  To clean things up, you need to
 819transplant the commits on 'topic' to the new 'subsystem' tip, i.e.,
 820rebase 'topic'.  This becomes a ripple effect: anyone downstream from
 821'topic' is forced to rebase too, and so on!
 822
 823There are two kinds of fixes, discussed in the following subsections:
 824
 825Easy case: The changes are literally the same.::
 826
 827        This happens if the 'subsystem' rebase was a simple rebase and
 828        had no conflicts.
 829
 830Hard case: The changes are not the same.::
 831
 832        This happens if the 'subsystem' rebase had conflicts, or used
 833        `--interactive` to omit, edit, squash, or fixup commits; or
 834        if the upstream used one of `commit --amend`, `reset`, or
 835        `filter-branch`.
 836
 837
 838The easy case
 839~~~~~~~~~~~~~
 840
 841Only works if the changes (patch IDs based on the diff contents) on
 842'subsystem' are literally the same before and after the rebase
 843'subsystem' did.
 844
 845In that case, the fix is easy because 'git rebase' knows to skip
 846changes that are already present in the new upstream.  So if you say
 847(assuming you're on 'topic')
 848------------
 849    $ git rebase subsystem
 850------------
 851you will end up with the fixed history
 852------------
 853    o---o---o---o---o---o---o---o  master
 854                                 \
 855                                  o'--o'--o'--o'--o'  subsystem
 856                                                   \
 857                                                    *---*---*  topic
 858------------
 859
 860
 861The hard case
 862~~~~~~~~~~~~~
 863
 864Things get more complicated if the 'subsystem' changes do not exactly
 865correspond to the ones before the rebase.
 866
 867NOTE: While an "easy case recovery" sometimes appears to be successful
 868      even in the hard case, it may have unintended consequences.  For
 869      example, a commit that was removed via `git rebase
 870      --interactive` will be **resurrected**!
 871
 872The idea is to manually tell 'git rebase' "where the old 'subsystem'
 873ended and your 'topic' began", that is, what the old merge-base
 874between them was.  You will have to find a way to name the last commit
 875of the old 'subsystem', for example:
 876
 877* With the 'subsystem' reflog: after 'git fetch', the old tip of
 878  'subsystem' is at `subsystem@{1}`.  Subsequent fetches will
 879  increase the number.  (See linkgit:git-reflog[1].)
 880
 881* Relative to the tip of 'topic': knowing that your 'topic' has three
 882  commits, the old tip of 'subsystem' must be `topic~3`.
 883
 884You can then transplant the old `subsystem..topic` to the new tip by
 885saying (for the reflog case, and assuming you are on 'topic' already):
 886------------
 887    $ git rebase --onto subsystem subsystem@{1}
 888------------
 889
 890The ripple effect of a "hard case" recovery is especially bad:
 891'everyone' downstream from 'topic' will now have to perform a "hard
 892case" recovery too!
 893
 894REBASING MERGES
 895---------------
 896
 897The interactive rebase command was originally designed to handle
 898individual patch series. As such, it makes sense to exclude merge
 899commits from the todo list, as the developer may have merged the
 900then-current `master` while working on the branch, only to rebase
 901all the commits onto `master` eventually (skipping the merge
 902commits).
 903
 904However, there are legitimate reasons why a developer may want to
 905recreate merge commits: to keep the branch structure (or "commit
 906topology") when working on multiple, inter-related branches.
 907
 908In the following example, the developer works on a topic branch that
 909refactors the way buttons are defined, and on another topic branch
 910that uses that refactoring to implement a "Report a bug" button. The
 911output of `git log --graph --format=%s -5` may look like this:
 912
 913------------
 914*   Merge branch 'report-a-bug'
 915|\
 916| * Add the feedback button
 917* | Merge branch 'refactor-button'
 918|\ \
 919| |/
 920| * Use the Button class for all buttons
 921| * Extract a generic Button class from the DownloadButton one
 922------------
 923
 924The developer might want to rebase those commits to a newer `master`
 925while keeping the branch topology, for example when the first topic
 926branch is expected to be integrated into `master` much earlier than the
 927second one, say, to resolve merge conflicts with changes to the
 928DownloadButton class that made it into `master`.
 929
 930This rebase can be performed using the `--rebase-merges` option.
 931It will generate a todo list looking like this:
 932
 933------------
 934label onto
 935
 936# Branch: refactor-button
 937reset onto
 938pick 123456 Extract a generic Button class from the DownloadButton one
 939pick 654321 Use the Button class for all buttons
 940label refactor-button
 941
 942# Branch: report-a-bug
 943reset refactor-button # Use the Button class for all buttons
 944pick abcdef Add the feedback button
 945label report-a-bug
 946
 947reset onto
 948merge -C a1b2c3 refactor-button # Merge 'refactor-button'
 949merge -C 6f5e4d report-a-bug # Merge 'report-a-bug'
 950------------
 951
 952In contrast to a regular interactive rebase, there are `label`, `reset`
 953and `merge` commands in addition to `pick` ones.
 954
 955The `label` command associates a label with the current HEAD when that
 956command is executed. These labels are created as worktree-local refs
 957(`refs/rewritten/<label>`) that will be deleted when the rebase
 958finishes. That way, rebase operations in multiple worktrees linked to
 959the same repository do not interfere with one another. If the `label`
 960command fails, it is rescheduled immediately, with a helpful message how
 961to proceed.
 962
 963The `reset` command resets the HEAD, index and worktree to the specified
 964revision. It is similar to an `exec git reset --hard <label>`, but
 965refuses to overwrite untracked files. If the `reset` command fails, it is
 966rescheduled immediately, with a helpful message how to edit the todo list
 967(this typically happens when a `reset` command was inserted into the todo
 968list manually and contains a typo).
 969
 970The `merge` command will merge the specified revision(s) into whatever
 971is HEAD at that time. With `-C <original-commit>`, the commit message of
 972the specified merge commit will be used. When the `-C` is changed to
 973a lower-case `-c`, the message will be opened in an editor after a
 974successful merge so that the user can edit the message.
 975
 976If a `merge` command fails for any reason other than merge conflicts (i.e.
 977when the merge operation did not even start), it is rescheduled immediately.
 978
 979At this time, the `merge` command will *always* use the `recursive`
 980merge strategy for regular merges, and `octopus` for octopus merges,
 981with no way to choose a different one. To work around
 982this, an `exec` command can be used to call `git merge` explicitly,
 983using the fact that the labels are worktree-local refs (the ref
 984`refs/rewritten/onto` would correspond to the label `onto`, for example).
 985
 986Note: the first command (`label onto`) labels the revision onto which
 987the commits are rebased; The name `onto` is just a convention, as a nod
 988to the `--onto` option.
 989
 990It is also possible to introduce completely new merge commits from scratch
 991by adding a command of the form `merge <merge-head>`. This form will
 992generate a tentative commit message and always open an editor to let the
 993user edit it. This can be useful e.g. when a topic branch turns out to
 994address more than a single concern and wants to be split into two or
 995even more topic branches. Consider this todo list:
 996
 997------------
 998pick 192837 Switch from GNU Makefiles to CMake
 999pick 5a6c7e Document the switch to CMake
1000pick 918273 Fix detection of OpenSSL in CMake
1001pick afbecd http: add support for TLS v1.3
1002pick fdbaec Fix detection of cURL in CMake on Windows
1003------------
1004
1005The one commit in this list that is not related to CMake may very well
1006have been motivated by working on fixing all those bugs introduced by
1007switching to CMake, but it addresses a different concern. To split this
1008branch into two topic branches, the todo list could be edited like this:
1009
1010------------
1011label onto
1012
1013pick afbecd http: add support for TLS v1.3
1014label tlsv1.3
1015
1016reset onto
1017pick 192837 Switch from GNU Makefiles to CMake
1018pick 918273 Fix detection of OpenSSL in CMake
1019pick fdbaec Fix detection of cURL in CMake on Windows
1020pick 5a6c7e Document the switch to CMake
1021label cmake
1022
1023reset onto
1024merge tlsv1.3
1025merge cmake
1026------------
1027
1028BUGS
1029----
1030The todo list presented by the deprecated `--preserve-merges --interactive`
1031does not represent the topology of the revision graph (use `--rebase-merges`
1032instead).  Editing commits and rewording their commit messages should work
1033fine, but attempts to reorder commits tend to produce counterintuitive results.
1034Use `--rebase-merges` in such scenarios instead.
1035
1036For example, an attempt to rearrange
1037------------
10381 --- 2 --- 3 --- 4 --- 5
1039------------
1040to
1041------------
10421 --- 2 --- 4 --- 3 --- 5
1043------------
1044by moving the "pick 4" line will result in the following history:
1045------------
1046        3
1047       /
10481 --- 2 --- 4 --- 5
1049------------
1050
1051GIT
1052---
1053Part of the linkgit:git[1] suite