Documentation / git-rebase.txton commit Merge branch 'sg/clean-nested-repo-with-ignored' (026428c)
   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 switch <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
 547BEHAVIORAL DIFFERENCES
 548-----------------------
 549
 550There are some subtle differences how the backends behave.
 551
 552Empty commits
 553~~~~~~~~~~~~~
 554
 555The am backend drops any "empty" commits, regardless of whether the
 556commit started empty (had no changes relative to its parent to
 557start with) or ended empty (all changes were already applied
 558upstream in other commits).
 559
 560The interactive backend drops commits by default that
 561started empty and halts if it hits a commit that ended up empty.
 562The `--keep-empty` option exists for the interactive backend to allow
 563it to keep commits that started empty.
 564
 565Directory rename detection
 566~~~~~~~~~~~~~~~~~~~~~~~~~~
 567
 568Directory rename heuristics are enabled in the merge and interactive
 569backends.  Due to the lack of accurate tree information, directory
 570rename detection is disabled in the am backend.
 571
 572include::merge-strategies.txt[]
 573
 574NOTES
 575-----
 576
 577You should understand the implications of using 'git rebase' on a
 578repository that you share.  See also RECOVERING FROM UPSTREAM REBASE
 579below.
 580
 581When the git-rebase command is run, it will first execute a "pre-rebase"
 582hook if one exists.  You can use this hook to do sanity checks and
 583reject the rebase if it isn't appropriate.  Please see the template
 584pre-rebase hook script for an example.
 585
 586Upon completion, <branch> will be the current branch.
 587
 588INTERACTIVE MODE
 589----------------
 590
 591Rebasing interactively means that you have a chance to edit the commits
 592which are rebased.  You can reorder the commits, and you can
 593remove them (weeding out bad or otherwise unwanted patches).
 594
 595The interactive mode is meant for this type of workflow:
 596
 5971. have a wonderful idea
 5982. hack on the code
 5993. prepare a series for submission
 6004. submit
 601
 602where point 2. consists of several instances of
 603
 604a) regular use
 605
 606 1. finish something worthy of a commit
 607 2. commit
 608
 609b) independent fixup
 610
 611 1. realize that something does not work
 612 2. fix that
 613 3. commit it
 614
 615Sometimes the thing fixed in b.2. cannot be amended to the not-quite
 616perfect commit it fixes, because that commit is buried deeply in a
 617patch series.  That is exactly what interactive rebase is for: use it
 618after plenty of "a"s and "b"s, by rearranging and editing
 619commits, and squashing multiple commits into one.
 620
 621Start it with the last commit you want to retain as-is:
 622
 623        git rebase -i <after-this-commit>
 624
 625An editor will be fired up with all the commits in your current branch
 626(ignoring merge commits), which come after the given commit.  You can
 627reorder the commits in this list to your heart's content, and you can
 628remove them.  The list looks more or less like this:
 629
 630-------------------------------------------
 631pick deadbee The oneline of this commit
 632pick fa1afe1 The oneline of the next commit
 633...
 634-------------------------------------------
 635
 636The oneline descriptions are purely for your pleasure; 'git rebase' will
 637not look at them but at the commit names ("deadbee" and "fa1afe1" in this
 638example), so do not delete or edit the names.
 639
 640By replacing the command "pick" with the command "edit", you can tell
 641'git rebase' to stop after applying that commit, so that you can edit
 642the files and/or the commit message, amend the commit, and continue
 643rebasing.
 644
 645To interrupt the rebase (just like an "edit" command would do, but without
 646cherry-picking any commit first), use the "break" command.
 647
 648If you just want to edit the commit message for a commit, replace the
 649command "pick" with the command "reword".
 650
 651To drop a commit, replace the command "pick" with "drop", or just
 652delete the matching line.
 653
 654If you want to fold two or more commits into one, replace the command
 655"pick" for the second and subsequent commits with "squash" or "fixup".
 656If the commits had different authors, the folded commit will be
 657attributed to the author of the first commit.  The suggested commit
 658message for the folded commit is the concatenation of the commit
 659messages of the first commit and of those with the "squash" command,
 660but omits the commit messages of commits with the "fixup" command.
 661
 662'git rebase' will stop when "pick" has been replaced with "edit" or
 663when a command fails due to merge errors. When you are done editing
 664and/or resolving conflicts you can continue with `git rebase --continue`.
 665
 666For example, if you want to reorder the last 5 commits, such that what
 667was HEAD~4 becomes the new HEAD. To achieve that, you would call
 668'git rebase' like this:
 669
 670----------------------
 671$ git rebase -i HEAD~5
 672----------------------
 673
 674And move the first patch to the end of the list.
 675
 676You might want to recreate merge commits, e.g. if you have a history
 677like this:
 678
 679------------------
 680           X
 681            \
 682         A---M---B
 683        /
 684---o---O---P---Q
 685------------------
 686
 687Suppose you want to rebase the side branch starting at "A" to "Q". Make
 688sure that the current HEAD is "B", and call
 689
 690-----------------------------
 691$ git rebase -i -r --onto Q O
 692-----------------------------
 693
 694Reordering and editing commits usually creates untested intermediate
 695steps.  You may want to check that your history editing did not break
 696anything by running a test, or at least recompiling at intermediate
 697points in history by using the "exec" command (shortcut "x").  You may
 698do so by creating a todo list like this one:
 699
 700-------------------------------------------
 701pick deadbee Implement feature XXX
 702fixup f1a5c00 Fix to feature XXX
 703exec make
 704pick c0ffeee The oneline of the next commit
 705edit deadbab The oneline of the commit after
 706exec cd subdir; make test
 707...
 708-------------------------------------------
 709
 710The interactive rebase will stop when a command fails (i.e. exits with
 711non-0 status) to give you an opportunity to fix the problem. You can
 712continue with `git rebase --continue`.
 713
 714The "exec" command launches the command in a shell (the one specified
 715in `$SHELL`, or the default shell if `$SHELL` is not set), so you can
 716use shell features (like "cd", ">", ";" ...). The command is run from
 717the root of the working tree.
 718
 719----------------------------------
 720$ git rebase -i --exec "make test"
 721----------------------------------
 722
 723This command lets you check that intermediate commits are compilable.
 724The todo list becomes like that:
 725
 726--------------------
 727pick 5928aea one
 728exec make test
 729pick 04d0fda two
 730exec make test
 731pick ba46169 three
 732exec make test
 733pick f4593f9 four
 734exec make test
 735--------------------
 736
 737SPLITTING COMMITS
 738-----------------
 739
 740In interactive mode, you can mark commits with the action "edit".  However,
 741this does not necessarily mean that 'git rebase' expects the result of this
 742edit to be exactly one commit.  Indeed, you can undo the commit, or you can
 743add other commits.  This can be used to split a commit into two:
 744
 745- Start an interactive rebase with `git rebase -i <commit>^`, where
 746  <commit> is the commit you want to split.  In fact, any commit range
 747  will do, as long as it contains that commit.
 748
 749- Mark the commit you want to split with the action "edit".
 750
 751- When it comes to editing that commit, execute `git reset HEAD^`.  The
 752  effect is that the HEAD is rewound by one, and the index follows suit.
 753  However, the working tree stays the same.
 754
 755- Now add the changes to the index that you want to have in the first
 756  commit.  You can use `git add` (possibly interactively) or
 757  'git gui' (or both) to do that.
 758
 759- Commit the now-current index with whatever commit message is appropriate
 760  now.
 761
 762- Repeat the last two steps until your working tree is clean.
 763
 764- Continue the rebase with `git rebase --continue`.
 765
 766If you are not absolutely sure that the intermediate revisions are
 767consistent (they compile, pass the testsuite, etc.) you should use
 768'git stash' to stash away the not-yet-committed changes
 769after each commit, test, and amend the commit if fixes are necessary.
 770
 771
 772RECOVERING FROM UPSTREAM REBASE
 773-------------------------------
 774
 775Rebasing (or any other form of rewriting) a branch that others have
 776based work on is a bad idea: anyone downstream of it is forced to
 777manually fix their history.  This section explains how to do the fix
 778from the downstream's point of view.  The real fix, however, would be
 779to avoid rebasing the upstream in the first place.
 780
 781To illustrate, suppose you are in a situation where someone develops a
 782'subsystem' branch, and you are working on a 'topic' that is dependent
 783on this 'subsystem'.  You might end up with a history like the
 784following:
 785
 786------------
 787    o---o---o---o---o---o---o---o  master
 788         \
 789          o---o---o---o---o  subsystem
 790                           \
 791                            *---*---*  topic
 792------------
 793
 794If 'subsystem' is rebased against 'master', the following happens:
 795
 796------------
 797    o---o---o---o---o---o---o---o  master
 798         \                       \
 799          o---o---o---o---o       o'--o'--o'--o'--o'  subsystem
 800                           \
 801                            *---*---*  topic
 802------------
 803
 804If you now continue development as usual, and eventually merge 'topic'
 805to 'subsystem', the commits from 'subsystem' will remain duplicated forever:
 806
 807------------
 808    o---o---o---o---o---o---o---o  master
 809         \                       \
 810          o---o---o---o---o       o'--o'--o'--o'--o'--M  subsystem
 811                           \                         /
 812                            *---*---*-..........-*--*  topic
 813------------
 814
 815Such duplicates are generally frowned upon because they clutter up
 816history, making it harder to follow.  To clean things up, you need to
 817transplant the commits on 'topic' to the new 'subsystem' tip, i.e.,
 818rebase 'topic'.  This becomes a ripple effect: anyone downstream from
 819'topic' is forced to rebase too, and so on!
 820
 821There are two kinds of fixes, discussed in the following subsections:
 822
 823Easy case: The changes are literally the same.::
 824
 825        This happens if the 'subsystem' rebase was a simple rebase and
 826        had no conflicts.
 827
 828Hard case: The changes are not the same.::
 829
 830        This happens if the 'subsystem' rebase had conflicts, or used
 831        `--interactive` to omit, edit, squash, or fixup commits; or
 832        if the upstream used one of `commit --amend`, `reset`, or
 833        a full history rewriting command like
 834        https://github.com/newren/git-filter-repo[`filter-repo`].
 835
 836
 837The easy case
 838~~~~~~~~~~~~~
 839
 840Only works if the changes (patch IDs based on the diff contents) on
 841'subsystem' are literally the same before and after the rebase
 842'subsystem' did.
 843
 844In that case, the fix is easy because 'git rebase' knows to skip
 845changes that are already present in the new upstream.  So if you say
 846(assuming you're on 'topic')
 847------------
 848    $ git rebase subsystem
 849------------
 850you will end up with the fixed history
 851------------
 852    o---o---o---o---o---o---o---o  master
 853                                 \
 854                                  o'--o'--o'--o'--o'  subsystem
 855                                                   \
 856                                                    *---*---*  topic
 857------------
 858
 859
 860The hard case
 861~~~~~~~~~~~~~
 862
 863Things get more complicated if the 'subsystem' changes do not exactly
 864correspond to the ones before the rebase.
 865
 866NOTE: While an "easy case recovery" sometimes appears to be successful
 867      even in the hard case, it may have unintended consequences.  For
 868      example, a commit that was removed via `git rebase
 869      --interactive` will be **resurrected**!
 870
 871The idea is to manually tell 'git rebase' "where the old 'subsystem'
 872ended and your 'topic' began", that is, what the old merge-base
 873between them was.  You will have to find a way to name the last commit
 874of the old 'subsystem', for example:
 875
 876* With the 'subsystem' reflog: after 'git fetch', the old tip of
 877  'subsystem' is at `subsystem@{1}`.  Subsequent fetches will
 878  increase the number.  (See linkgit:git-reflog[1].)
 879
 880* Relative to the tip of 'topic': knowing that your 'topic' has three
 881  commits, the old tip of 'subsystem' must be `topic~3`.
 882
 883You can then transplant the old `subsystem..topic` to the new tip by
 884saying (for the reflog case, and assuming you are on 'topic' already):
 885------------
 886    $ git rebase --onto subsystem subsystem@{1}
 887------------
 888
 889The ripple effect of a "hard case" recovery is especially bad:
 890'everyone' downstream from 'topic' will now have to perform a "hard
 891case" recovery too!
 892
 893REBASING MERGES
 894---------------
 895
 896The interactive rebase command was originally designed to handle
 897individual patch series. As such, it makes sense to exclude merge
 898commits from the todo list, as the developer may have merged the
 899then-current `master` while working on the branch, only to rebase
 900all the commits onto `master` eventually (skipping the merge
 901commits).
 902
 903However, there are legitimate reasons why a developer may want to
 904recreate merge commits: to keep the branch structure (or "commit
 905topology") when working on multiple, inter-related branches.
 906
 907In the following example, the developer works on a topic branch that
 908refactors the way buttons are defined, and on another topic branch
 909that uses that refactoring to implement a "Report a bug" button. The
 910output of `git log --graph --format=%s -5` may look like this:
 911
 912------------
 913*   Merge branch 'report-a-bug'
 914|\
 915| * Add the feedback button
 916* | Merge branch 'refactor-button'
 917|\ \
 918| |/
 919| * Use the Button class for all buttons
 920| * Extract a generic Button class from the DownloadButton one
 921------------
 922
 923The developer might want to rebase those commits to a newer `master`
 924while keeping the branch topology, for example when the first topic
 925branch is expected to be integrated into `master` much earlier than the
 926second one, say, to resolve merge conflicts with changes to the
 927DownloadButton class that made it into `master`.
 928
 929This rebase can be performed using the `--rebase-merges` option.
 930It will generate a todo list looking like this:
 931
 932------------
 933label onto
 934
 935# Branch: refactor-button
 936reset onto
 937pick 123456 Extract a generic Button class from the DownloadButton one
 938pick 654321 Use the Button class for all buttons
 939label refactor-button
 940
 941# Branch: report-a-bug
 942reset refactor-button # Use the Button class for all buttons
 943pick abcdef Add the feedback button
 944label report-a-bug
 945
 946reset onto
 947merge -C a1b2c3 refactor-button # Merge 'refactor-button'
 948merge -C 6f5e4d report-a-bug # Merge 'report-a-bug'
 949------------
 950
 951In contrast to a regular interactive rebase, there are `label`, `reset`
 952and `merge` commands in addition to `pick` ones.
 953
 954The `label` command associates a label with the current HEAD when that
 955command is executed. These labels are created as worktree-local refs
 956(`refs/rewritten/<label>`) that will be deleted when the rebase
 957finishes. That way, rebase operations in multiple worktrees linked to
 958the same repository do not interfere with one another. If the `label`
 959command fails, it is rescheduled immediately, with a helpful message how
 960to proceed.
 961
 962The `reset` command resets the HEAD, index and worktree to the specified
 963revision. It is similar to an `exec git reset --hard <label>`, but
 964refuses to overwrite untracked files. If the `reset` command fails, it is
 965rescheduled immediately, with a helpful message how to edit the todo list
 966(this typically happens when a `reset` command was inserted into the todo
 967list manually and contains a typo).
 968
 969The `merge` command will merge the specified revision(s) into whatever
 970is HEAD at that time. With `-C <original-commit>`, the commit message of
 971the specified merge commit will be used. When the `-C` is changed to
 972a lower-case `-c`, the message will be opened in an editor after a
 973successful merge so that the user can edit the message.
 974
 975If a `merge` command fails for any reason other than merge conflicts (i.e.
 976when the merge operation did not even start), it is rescheduled immediately.
 977
 978At this time, the `merge` command will *always* use the `recursive`
 979merge strategy for regular merges, and `octopus` for octopus merges,
 980with no way to choose a different one. To work around
 981this, an `exec` command can be used to call `git merge` explicitly,
 982using the fact that the labels are worktree-local refs (the ref
 983`refs/rewritten/onto` would correspond to the label `onto`, for example).
 984
 985Note: the first command (`label onto`) labels the revision onto which
 986the commits are rebased; The name `onto` is just a convention, as a nod
 987to the `--onto` option.
 988
 989It is also possible to introduce completely new merge commits from scratch
 990by adding a command of the form `merge <merge-head>`. This form will
 991generate a tentative commit message and always open an editor to let the
 992user edit it. This can be useful e.g. when a topic branch turns out to
 993address more than a single concern and wants to be split into two or
 994even more topic branches. Consider this todo list:
 995
 996------------
 997pick 192837 Switch from GNU Makefiles to CMake
 998pick 5a6c7e Document the switch to CMake
 999pick 918273 Fix detection of OpenSSL in CMake
1000pick afbecd http: add support for TLS v1.3
1001pick fdbaec Fix detection of cURL in CMake on Windows
1002------------
1003
1004The one commit in this list that is not related to CMake may very well
1005have been motivated by working on fixing all those bugs introduced by
1006switching to CMake, but it addresses a different concern. To split this
1007branch into two topic branches, the todo list could be edited like this:
1008
1009------------
1010label onto
1011
1012pick afbecd http: add support for TLS v1.3
1013label tlsv1.3
1014
1015reset onto
1016pick 192837 Switch from GNU Makefiles to CMake
1017pick 918273 Fix detection of OpenSSL in CMake
1018pick fdbaec Fix detection of cURL in CMake on Windows
1019pick 5a6c7e Document the switch to CMake
1020label cmake
1021
1022reset onto
1023merge tlsv1.3
1024merge cmake
1025------------
1026
1027BUGS
1028----
1029The todo list presented by the deprecated `--preserve-merges --interactive`
1030does not represent the topology of the revision graph (use `--rebase-merges`
1031instead).  Editing commits and rewording their commit messages should work
1032fine, but attempts to reorder commits tend to produce counterintuitive results.
1033Use `--rebase-merges` in such scenarios instead.
1034
1035For example, an attempt to rearrange
1036------------
10371 --- 2 --- 3 --- 4 --- 5
1038------------
1039to
1040------------
10411 --- 2 --- 4 --- 3 --- 5
1042------------
1043by moving the "pick 4" line will result in the following history:
1044------------
1045        3
1046       /
10471 --- 2 --- 4 --- 5
1048------------
1049
1050GIT
1051---
1052Part of the linkgit:git[1] suite