Merge branch 'pw/rerere-autoupdate'
[git/git.git] / Documentation / git-rebase.txt
1 git-rebase(1)
2 =============
3
4 NAME
5 ----
6 git-rebase - Reapply commits on top of another base tip
7
8 SYNOPSIS
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
17 DESCRIPTION
18 -----------
19 If <branch> is specified, 'git rebase' will perform an automatic
20 `git checkout <branch>` before doing anything else. Otherwise
21 it remains on the current branch.
22
23 If <upstream> is not specified, the upstream configured in
24 branch.<name>.remote and branch.<name>.merge options will be used (see
25 linkgit:git-config[1] for details) and the `--fork-point` option is
26 assumed. If you are currently not on any branch or if the current
27 branch does not have a configured upstream, the rebase will abort.
28
29 All changes made by commits in the current branch but that are not
30 in <upstream> are saved to a temporary area. This is the same set
31 of 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
33 description on `--fork-point` below); or by `git log HEAD`, if the
34 `--root` option is specified.
35
36 The 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
39 to point at the tip of the branch before the reset.
40
41 The commits that were previously saved into the temporary area are
42 then reapplied to the current branch, one by one, in order. Note that
43 any commits in HEAD which introduce the same textual changes as a commit
44 in HEAD..<upstream> are omitted (i.e., a patch already accepted upstream
45 with a different commit message or timestamp will be skipped).
46
47 It is possible that a merge failure will prevent this process from being
48 completely automatic. You will have to resolve any such merge failure
49 and run `git rebase --continue`. Another option is to bypass the commit
50 that caused the merge failure with `git rebase --skip`. To check out the
51 original <branch> and remove the .git/rebase-apply working files, use the
52 command `git rebase --abort` instead.
53
54 Assume 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
62 From this point, the result of either of the following commands:
63
64
65 git rebase master
66 git rebase master topic
67
68 would 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`
77 followed by `git rebase master`. When rebase exits `topic` will
78 remain the checked-out branch.
79
80 If the upstream branch already contains a change you have made (e.g.,
81 because you mailed a patch which was applied upstream), then that commit
82 will be skipped. For example, running `git rebase master` on the
83 following history (in which `A'` and `A` introduce the same set of changes,
84 but have different committer information):
85
86 ------------
87 A---B---C topic
88 /
89 D---E---A'---F master
90 ------------
91
92 will result in:
93
94 ------------
95 B'---C' topic
96 /
97 D---E---A'---F master
98 ------------
99
100 Here is how you would transplant a topic branch based on one
101 branch to another, to pretend that you forked the topic branch
102 from the latter branch, using `rebase --onto`.
103
104 First let's assume your 'topic' is based on branch 'next'.
105 For example, a feature developed in 'topic' depends on some
106 functionality 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
116 We want to make 'topic' forked from branch 'master'; for example,
117 because the functionality on which 'topic' depends was merged into the
118 more 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
128 We can get this using the following command:
129
130 git rebase --onto master next topic
131
132
133 Another example of --onto option is to rebase part of a
134 branch. 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
144 then the command
145
146 git rebase --onto master topicA topicB
147
148 would result in:
149
150 ------------
151 H'--I'--J' topicB
152 /
153 | E---F---G topicA
154 |/
155 A---B---C---D master
156 ------------
157
158 This is useful when topicB does not depend on topicA.
159
160 A range of commits could also be removed with rebase. If we have
161 the following situation:
162
163 ------------
164 E---F---G---H---I---J topicA
165 ------------
166
167 then the command
168
169 git rebase --onto topicA~5 topicA~3 topicA
170
171 would result in the removal of commits F and G:
172
173 ------------
174 E---H'---I'---J' topicA
175 ------------
176
177 This is useful if F and G were flawed in some way, or should not be
178 part of topicA. Note that the argument to --onto and the <upstream>
179 parameter can be any valid commit-ish.
180
181 In case of conflict, 'git rebase' will stop at the first problematic commit
182 and leave conflict markers in the tree. You can use 'git diff' to locate
183 the markers (<<<<<<) and make edits to resolve the conflict. For each
184 file you edit, you need to tell Git that the conflict has been resolved,
185 typically this would be done with
186
187
188 git add <filename>
189
190
191 After resolving the conflict manually and updating the index with the
192 desired resolution, you can continue the rebasing process with
193
194
195 git rebase --continue
196
197
198 Alternatively, you can undo the 'git rebase' with
199
200
201 git rebase --abort
202
203 CONFIGURATION
204 -------------
205
206 include::config/rebase.txt[]
207
208 OPTIONS
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 +
216 As a special case, you may use "A\...B" as a shortcut for the
217 merge base of A and B if there is exactly one merge base. You can
218 leave 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 +
247 See 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 +
254 See 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 +
273 Note that a rebase merge works by replaying each commit from the working
274 branch on top of the <upstream> branch. Because of this, when a merge
275 conflict happens, the side reported as 'ours' is the so-far rebased
276 series, starting with <upstream>, and 'theirs' is the working branch. In
277 other words, the sides are swapped.
278 +
279 See 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 +
287 Because 'git rebase' replays each commit from the working branch
288 on top of the <upstream> branch using the given strategy, using
289 the 'ours' strategy simply empties all patches from the <branch>,
290 which makes little sense.
291 +
292 See 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 +
301 See 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 +
343 See 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 +
352 You may find this helpful after reverting a topic branch merge, as this option
353 recreates the topic branch with fresh commits so it can be remerged
354 successfully without needing to "revert the reversion" (see the
355 link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for
356 details).
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 +
364 When --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'
368 ends up being empty, the <upstream> will be used as a fallback.
369 +
370 If either <upstream> or --root is given on the command line, then the
371 default 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 +
378 See 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 +
385 See 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 +
392 See 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 +
400 The commit list format can be changed by setting the configuration option
401 rebase.instructionFormat. A customized instruction format will automatically
402 have the long commit hash prepended to the format.
403 +
404 See 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 +
416 By default, or when `no-rebase-cousins` was specified, commits which do not
417 have `<upstream>` as direct ancestor will keep their original branch point,
418 i.e. commits that would be excluded by linkgit:git-log[1]'s
419 `--ancestry-path` option will keep their original ancestry by default. If
420 the `rebase-cousins` mode is turned on, such commits are instead rebased
421 onto `<upstream>` (or `<onto>`, if specified).
422 +
423 The `--rebase-merges` mode is similar in spirit to the deprecated
424 `--preserve-merges`, but in contrast to that option works well in interactive
425 rebases: commits can be reordered, inserted and dropped at will.
426 +
427 It is currently only possible to recreate the merge commits using the
428 `recursive` merge strategy; Different merge strategies can be used only via
429 explicit `exec git merge -s <strategy> [...]` commands.
430 +
431 See 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 +
440 This uses the `--interactive` machinery internally, but combining it
441 with the `--interactive` option explicitly is generally not a good
442 idea unless you know what you are doing (see BUGS below).
443 +
444 See 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 +
453 You may execute several commands by either using one instance of `--exec`
454 with several commands:
455 +
456 git rebase -i --exec "cmd1 && cmd2 && ..."
457 +
458 or by giving more than one `--exec`:
459 +
460 git rebase -i --exec "cmd1" --exec "cmd2" --exec ...
461 +
462 If `--autosquash` is used, "exec" lines will not be appended for
463 the intermediate commits, and will only appear at the end of each
464 squash/fixup series.
465 +
466 This uses the `--interactive` machinery internally, but it can be run
467 without an explicit `--interactive`.
468 +
469 See 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 +
481 See 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 +
496 If the `--autosquash` option is enabled by default using the
497 configuration variable `rebase.autoSquash`, this option can be
498 used to override and disable this setting.
499 +
500 See 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
515 INCOMPATIBLE OPTIONS
516 --------------------
517
518 The following options:
519
520 * --committer-date-is-author-date
521 * --ignore-date
522 * --whitespace
523 * --ignore-whitespace
524 * -C
525
526 are 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
541 In 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
549 BEHAVIORAL DIFFERENCES
550 -----------------------
551
552 There are some subtle differences how the backends behave.
553
554 Empty commits
555 ~~~~~~~~~~~~~
556
557 The am backend drops any "empty" commits, regardless of whether the
558 commit started empty (had no changes relative to its parent to
559 start with) or ended empty (all changes were already applied
560 upstream in other commits).
561
562 The interactive backend drops commits by default that
563 started empty and halts if it hits a commit that ended up empty.
564 The `--keep-empty` option exists for the interactive backend to allow
565 it to keep commits that started empty.
566
567 Directory rename detection
568 ~~~~~~~~~~~~~~~~~~~~~~~~~~
569
570 Directory rename heuristics are enabled in the merge and interactive
571 backends. Due to the lack of accurate tree information, directory
572 rename detection is disabled in the am backend.
573
574 include::merge-strategies.txt[]
575
576 NOTES
577 -----
578
579 You should understand the implications of using 'git rebase' on a
580 repository that you share. See also RECOVERING FROM UPSTREAM REBASE
581 below.
582
583 When the git-rebase command is run, it will first execute a "pre-rebase"
584 hook if one exists. You can use this hook to do sanity checks and
585 reject the rebase if it isn't appropriate. Please see the template
586 pre-rebase hook script for an example.
587
588 Upon completion, <branch> will be the current branch.
589
590 INTERACTIVE MODE
591 ----------------
592
593 Rebasing interactively means that you have a chance to edit the commits
594 which are rebased. You can reorder the commits, and you can
595 remove them (weeding out bad or otherwise unwanted patches).
596
597 The interactive mode is meant for this type of workflow:
598
599 1. have a wonderful idea
600 2. hack on the code
601 3. prepare a series for submission
602 4. submit
603
604 where point 2. consists of several instances of
605
606 a) regular use
607
608 1. finish something worthy of a commit
609 2. commit
610
611 b) independent fixup
612
613 1. realize that something does not work
614 2. fix that
615 3. commit it
616
617 Sometimes the thing fixed in b.2. cannot be amended to the not-quite
618 perfect commit it fixes, because that commit is buried deeply in a
619 patch series. That is exactly what interactive rebase is for: use it
620 after plenty of "a"s and "b"s, by rearranging and editing
621 commits, and squashing multiple commits into one.
622
623 Start it with the last commit you want to retain as-is:
624
625 git rebase -i <after-this-commit>
626
627 An 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
629 reorder the commits in this list to your heart's content, and you can
630 remove them. The list looks more or less like this:
631
632 -------------------------------------------
633 pick deadbee The oneline of this commit
634 pick fa1afe1 The oneline of the next commit
635 ...
636 -------------------------------------------
637
638 The oneline descriptions are purely for your pleasure; 'git rebase' will
639 not look at them but at the commit names ("deadbee" and "fa1afe1" in this
640 example), so do not delete or edit the names.
641
642 By 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
644 the files and/or the commit message, amend the commit, and continue
645 rebasing.
646
647 To interrupt the rebase (just like an "edit" command would do, but without
648 cherry-picking any commit first), use the "break" command.
649
650 If you just want to edit the commit message for a commit, replace the
651 command "pick" with the command "reword".
652
653 To drop a commit, replace the command "pick" with "drop", or just
654 delete the matching line.
655
656 If 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".
658 If the commits had different authors, the folded commit will be
659 attributed to the author of the first commit. The suggested commit
660 message for the folded commit is the concatenation of the commit
661 messages of the first commit and of those with the "squash" command,
662 but omits the commit messages of commits with the "fixup" command.
663
664 'git rebase' will stop when "pick" has been replaced with "edit" or
665 when a command fails due to merge errors. When you are done editing
666 and/or resolving conflicts you can continue with `git rebase --continue`.
667
668 For example, if you want to reorder the last 5 commits, such that what
669 was 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
676 And move the first patch to the end of the list.
677
678 You might want to preserve merges, if you have a history like this:
679
680 ------------------
681 X
682 \
683 A---M---B
684 /
685 ---o---O---P---Q
686 ------------------
687
688 Suppose you want to rebase the side branch starting at "A" to "Q". Make
689 sure that the current HEAD is "B", and call
690
691 -----------------------------
692 $ git rebase -i -p --onto Q O
693 -----------------------------
694
695 Reordering and editing commits usually creates untested intermediate
696 steps. You may want to check that your history editing did not break
697 anything by running a test, or at least recompiling at intermediate
698 points in history by using the "exec" command (shortcut "x"). You may
699 do so by creating a todo list like this one:
700
701 -------------------------------------------
702 pick deadbee Implement feature XXX
703 fixup f1a5c00 Fix to feature XXX
704 exec make
705 pick c0ffeee The oneline of the next commit
706 edit deadbab The oneline of the commit after
707 exec cd subdir; make test
708 ...
709 -------------------------------------------
710
711 The interactive rebase will stop when a command fails (i.e. exits with
712 non-0 status) to give you an opportunity to fix the problem. You can
713 continue with `git rebase --continue`.
714
715 The "exec" command launches the command in a shell (the one specified
716 in `$SHELL`, or the default shell if `$SHELL` is not set), so you can
717 use shell features (like "cd", ">", ";" ...). The command is run from
718 the root of the working tree.
719
720 ----------------------------------
721 $ git rebase -i --exec "make test"
722 ----------------------------------
723
724 This command lets you check that intermediate commits are compilable.
725 The todo list becomes like that:
726
727 --------------------
728 pick 5928aea one
729 exec make test
730 pick 04d0fda two
731 exec make test
732 pick ba46169 three
733 exec make test
734 pick f4593f9 four
735 exec make test
736 --------------------
737
738 SPLITTING COMMITS
739 -----------------
740
741 In interactive mode, you can mark commits with the action "edit". However,
742 this does not necessarily mean that 'git rebase' expects the result of this
743 edit to be exactly one commit. Indeed, you can undo the commit, or you can
744 add other commits. This can be used to split a commit into two:
745
746 - Start an interactive rebase with `git rebase -i <commit>^`, where
747 <commit> is the commit you want to split. In fact, any commit range
748 will do, as long as it contains that commit.
749
750 - Mark the commit you want to split with the action "edit".
751
752 - When it comes to editing that commit, execute `git reset HEAD^`. The
753 effect is that the HEAD is rewound by one, and the index follows suit.
754 However, the working tree stays the same.
755
756 - Now add the changes to the index that you want to have in the first
757 commit. You can use `git add` (possibly interactively) or
758 'git gui' (or both) to do that.
759
760 - Commit the now-current index with whatever commit message is appropriate
761 now.
762
763 - Repeat the last two steps until your working tree is clean.
764
765 - Continue the rebase with `git rebase --continue`.
766
767 If you are not absolutely sure that the intermediate revisions are
768 consistent (they compile, pass the testsuite, etc.) you should use
769 'git stash' to stash away the not-yet-committed changes
770 after each commit, test, and amend the commit if fixes are necessary.
771
772
773 RECOVERING FROM UPSTREAM REBASE
774 -------------------------------
775
776 Rebasing (or any other form of rewriting) a branch that others have
777 based work on is a bad idea: anyone downstream of it is forced to
778 manually fix their history. This section explains how to do the fix
779 from the downstream's point of view. The real fix, however, would be
780 to avoid rebasing the upstream in the first place.
781
782 To illustrate, suppose you are in a situation where someone develops a
783 'subsystem' branch, and you are working on a 'topic' that is dependent
784 on this 'subsystem'. You might end up with a history like the
785 following:
786
787 ------------
788 o---o---o---o---o---o---o---o master
789 \
790 o---o---o---o---o subsystem
791 \
792 *---*---* topic
793 ------------
794
795 If 'subsystem' is rebased against 'master', the following happens:
796
797 ------------
798 o---o---o---o---o---o---o---o master
799 \ \
800 o---o---o---o---o o'--o'--o'--o'--o' subsystem
801 \
802 *---*---* topic
803 ------------
804
805 If you now continue development as usual, and eventually merge 'topic'
806 to 'subsystem', the commits from 'subsystem' will remain duplicated forever:
807
808 ------------
809 o---o---o---o---o---o---o---o master
810 \ \
811 o---o---o---o---o o'--o'--o'--o'--o'--M subsystem
812 \ /
813 *---*---*-..........-*--* topic
814 ------------
815
816 Such duplicates are generally frowned upon because they clutter up
817 history, making it harder to follow. To clean things up, you need to
818 transplant the commits on 'topic' to the new 'subsystem' tip, i.e.,
819 rebase 'topic'. This becomes a ripple effect: anyone downstream from
820 'topic' is forced to rebase too, and so on!
821
822 There are two kinds of fixes, discussed in the following subsections:
823
824 Easy case: The changes are literally the same.::
825
826 This happens if the 'subsystem' rebase was a simple rebase and
827 had no conflicts.
828
829 Hard case: The changes are not the same.::
830
831 This happens if the 'subsystem' rebase had conflicts, or used
832 `--interactive` to omit, edit, squash, or fixup commits; or
833 if the upstream used one of `commit --amend`, `reset`, or
834 `filter-branch`.
835
836
837 The easy case
838 ~~~~~~~~~~~~~
839
840 Only 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
844 In that case, the fix is easy because 'git rebase' knows to skip
845 changes that are already present in the new upstream. So if you say
846 (assuming you're on 'topic')
847 ------------
848 $ git rebase subsystem
849 ------------
850 you 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
860 The hard case
861 ~~~~~~~~~~~~~
862
863 Things get more complicated if the 'subsystem' changes do not exactly
864 correspond to the ones before the rebase.
865
866 NOTE: 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
871 The idea is to manually tell 'git rebase' "where the old 'subsystem'
872 ended and your 'topic' began", that is, what the old merge-base
873 between them was. You will have to find a way to name the last commit
874 of 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
883 You can then transplant the old `subsystem..topic` to the new tip by
884 saying (for the reflog case, and assuming you are on 'topic' already):
885 ------------
886 $ git rebase --onto subsystem subsystem@{1}
887 ------------
888
889 The ripple effect of a "hard case" recovery is especially bad:
890 'everyone' downstream from 'topic' will now have to perform a "hard
891 case" recovery too!
892
893 REBASING MERGES
894 ---------------
895
896 The interactive rebase command was originally designed to handle
897 individual patch series. As such, it makes sense to exclude merge
898 commits from the todo list, as the developer may have merged the
899 then-current `master` while working on the branch, only to rebase
900 all the commits onto `master` eventually (skipping the merge
901 commits).
902
903 However, there are legitimate reasons why a developer may want to
904 recreate merge commits: to keep the branch structure (or "commit
905 topology") when working on multiple, inter-related branches.
906
907 In the following example, the developer works on a topic branch that
908 refactors the way buttons are defined, and on another topic branch
909 that uses that refactoring to implement a "Report a bug" button. The
910 output 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
923 The developer might want to rebase those commits to a newer `master`
924 while keeping the branch topology, for example when the first topic
925 branch is expected to be integrated into `master` much earlier than the
926 second one, say, to resolve merge conflicts with changes to the
927 DownloadButton class that made it into `master`.
928
929 This rebase can be performed using the `--rebase-merges` option.
930 It will generate a todo list looking like this:
931
932 ------------
933 label onto
934
935 # Branch: refactor-button
936 reset onto
937 pick 123456 Extract a generic Button class from the DownloadButton one
938 pick 654321 Use the Button class for all buttons
939 label refactor-button
940
941 # Branch: report-a-bug
942 reset refactor-button # Use the Button class for all buttons
943 pick abcdef Add the feedback button
944 label report-a-bug
945
946 reset onto
947 merge -C a1b2c3 refactor-button # Merge 'refactor-button'
948 merge -C 6f5e4d report-a-bug # Merge 'report-a-bug'
949 ------------
950
951 In contrast to a regular interactive rebase, there are `label`, `reset`
952 and `merge` commands in addition to `pick` ones.
953
954 The `label` command associates a label with the current HEAD when that
955 command is executed. These labels are created as worktree-local refs
956 (`refs/rewritten/<label>`) that will be deleted when the rebase
957 finishes. That way, rebase operations in multiple worktrees linked to
958 the same repository do not interfere with one another. If the `label`
959 command fails, it is rescheduled immediately, with a helpful message how
960 to proceed.
961
962 The `reset` command resets the HEAD, index and worktree to the specified
963 revision. It is similar to an `exec git reset --hard <label>`, but
964 refuses to overwrite untracked files. If the `reset` command fails, it is
965 rescheduled immediately, with a helpful message how to edit the todo list
966 (this typically happens when a `reset` command was inserted into the todo
967 list manually and contains a typo).
968
969 The `merge` command will merge the specified revision(s) into whatever
970 is HEAD at that time. With `-C <original-commit>`, the commit message of
971 the specified merge commit will be used. When the `-C` is changed to
972 a lower-case `-c`, the message will be opened in an editor after a
973 successful merge so that the user can edit the message.
974
975 If a `merge` command fails for any reason other than merge conflicts (i.e.
976 when the merge operation did not even start), it is rescheduled immediately.
977
978 At this time, the `merge` command will *always* use the `recursive`
979 merge strategy for regular merges, and `octopus` for octopus merges,
980 with no way to choose a different one. To work around
981 this, an `exec` command can be used to call `git merge` explicitly,
982 using the fact that the labels are worktree-local refs (the ref
983 `refs/rewritten/onto` would correspond to the label `onto`, for example).
984
985 Note: the first command (`label onto`) labels the revision onto which
986 the commits are rebased; The name `onto` is just a convention, as a nod
987 to the `--onto` option.
988
989 It is also possible to introduce completely new merge commits from scratch
990 by adding a command of the form `merge <merge-head>`. This form will
991 generate a tentative commit message and always open an editor to let the
992 user edit it. This can be useful e.g. when a topic branch turns out to
993 address more than a single concern and wants to be split into two or
994 even more topic branches. Consider this todo list:
995
996 ------------
997 pick 192837 Switch from GNU Makefiles to CMake
998 pick 5a6c7e Document the switch to CMake
999 pick 918273 Fix detection of OpenSSL in CMake
1000 pick afbecd http: add support for TLS v1.3
1001 pick fdbaec Fix detection of cURL in CMake on Windows
1002 ------------
1003
1004 The one commit in this list that is not related to CMake may very well
1005 have been motivated by working on fixing all those bugs introduced by
1006 switching to CMake, but it addresses a different concern. To split this
1007 branch into two topic branches, the todo list could be edited like this:
1008
1009 ------------
1010 label onto
1011
1012 pick afbecd http: add support for TLS v1.3
1013 label tlsv1.3
1014
1015 reset onto
1016 pick 192837 Switch from GNU Makefiles to CMake
1017 pick 918273 Fix detection of OpenSSL in CMake
1018 pick fdbaec Fix detection of cURL in CMake on Windows
1019 pick 5a6c7e Document the switch to CMake
1020 label cmake
1021
1022 reset onto
1023 merge tlsv1.3
1024 merge cmake
1025 ------------
1026
1027 BUGS
1028 ----
1029 The todo list presented by the deprecated `--preserve-merges --interactive`
1030 does not represent the topology of the revision graph (use `--rebase-merges`
1031 instead). Editing commits and rewording their commit messages should work
1032 fine, but attempts to reorder commits tend to produce counterintuitive results.
1033 Use `--rebase-merges` in such scenarios instead.
1034
1035 For example, an attempt to rearrange
1036 ------------
1037 1 --- 2 --- 3 --- 4 --- 5
1038 ------------
1039 to
1040 ------------
1041 1 --- 2 --- 4 --- 3 --- 5
1042 ------------
1043 by moving the "pick 4" line will result in the following history:
1044 ------------
1045 3
1046 /
1047 1 --- 2 --- 4 --- 5
1048 ------------
1049
1050 GIT
1051 ---
1052 Part of the linkgit:git[1] suite