am, rebase: teach quiet option
[git/git.git] / Documentation / git-rebase.txt
1 git-rebase(1)
2 =============
3
4 NAME
5 ----
6 git-rebase - Forward-port local commits to the updated upstream head
7
8 SYNOPSIS
9 --------
10 [verse]
11 'git rebase' [-i | --interactive] [options] [--onto <newbase>]
12 <upstream> [<branch>]
13 'git rebase' [-i | --interactive] [options] --onto <newbase>
14 --root [<branch>]
15
16 'git rebase' --continue | --skip | --abort
17
18 DESCRIPTION
19 -----------
20 If <branch> is specified, 'git-rebase' will perform an automatic
21 `git checkout <branch>` before doing anything else. Otherwise
22 it remains on the current branch.
23
24 All changes made by commits in the current branch but that are not
25 in <upstream> are saved to a temporary area. This is the same set
26 of commits that would be shown by `git log <upstream>..HEAD` (or
27 `git log HEAD`, if --root is specified).
28
29 The current branch is reset to <upstream>, or <newbase> if the
30 --onto option was supplied. This has the exact same effect as
31 `git reset --hard <upstream>` (or <newbase>). ORIG_HEAD is set
32 to point at the tip of the branch before the reset.
33
34 The commits that were previously saved into the temporary area are
35 then reapplied to the current branch, one by one, in order. Note that
36 any commits in HEAD which introduce the same textual changes as a commit
37 in HEAD..<upstream> are omitted (i.e., a patch already accepted upstream
38 with a different commit message or timestamp will be skipped).
39
40 It is possible that a merge failure will prevent this process from being
41 completely automatic. You will have to resolve any such merge failure
42 and run `git rebase --continue`. Another option is to bypass the commit
43 that caused the merge failure with `git rebase --skip`. To restore the
44 original <branch> and remove the .git/rebase-apply working files, use the
45 command `git rebase --abort` instead.
46
47 Assume the following history exists and the current branch is "topic":
48
49 ------------
50 A---B---C topic
51 /
52 D---E---F---G master
53 ------------
54
55 From this point, the result of either of the following commands:
56
57
58 git rebase master
59 git rebase master topic
60
61 would be:
62
63 ------------
64 A'--B'--C' topic
65 /
66 D---E---F---G master
67 ------------
68
69 The latter form is just a short-hand of `git checkout topic`
70 followed by `git rebase master`.
71
72 If the upstream branch already contains a change you have made (e.g.,
73 because you mailed a patch which was applied upstream), then that commit
74 will be skipped. For example, running `git rebase master` on the
75 following history (in which A' and A introduce the same set of changes,
76 but have different committer information):
77
78 ------------
79 A---B---C topic
80 /
81 D---E---A'---F master
82 ------------
83
84 will result in:
85
86 ------------
87 B'---C' topic
88 /
89 D---E---A'---F master
90 ------------
91
92 Here is how you would transplant a topic branch based on one
93 branch to another, to pretend that you forked the topic branch
94 from the latter branch, using `rebase --onto`.
95
96 First let's assume your 'topic' is based on branch 'next'.
97 For example, a feature developed in 'topic' depends on some
98 functionality which is found in 'next'.
99
100 ------------
101 o---o---o---o---o master
102 \
103 o---o---o---o---o next
104 \
105 o---o---o topic
106 ------------
107
108 We want to make 'topic' forked from branch 'master'; for example,
109 because the functionality on which 'topic' depends was merged into the
110 more stable 'master' branch. We want our tree to look like this:
111
112 ------------
113 o---o---o---o---o master
114 | \
115 | o'--o'--o' topic
116 \
117 o---o---o---o---o next
118 ------------
119
120 We can get this using the following command:
121
122 git rebase --onto master next topic
123
124
125 Another example of --onto option is to rebase part of a
126 branch. If we have the following situation:
127
128 ------------
129 H---I---J topicB
130 /
131 E---F---G topicA
132 /
133 A---B---C---D master
134 ------------
135
136 then the command
137
138 git rebase --onto master topicA topicB
139
140 would result in:
141
142 ------------
143 H'--I'--J' topicB
144 /
145 | E---F---G topicA
146 |/
147 A---B---C---D master
148 ------------
149
150 This is useful when topicB does not depend on topicA.
151
152 A range of commits could also be removed with rebase. If we have
153 the following situation:
154
155 ------------
156 E---F---G---H---I---J topicA
157 ------------
158
159 then the command
160
161 git rebase --onto topicA~5 topicA~3 topicA
162
163 would result in the removal of commits F and G:
164
165 ------------
166 E---H'---I'---J' topicA
167 ------------
168
169 This is useful if F and G were flawed in some way, or should not be
170 part of topicA. Note that the argument to --onto and the <upstream>
171 parameter can be any valid commit-ish.
172
173 In case of conflict, 'git-rebase' will stop at the first problematic commit
174 and leave conflict markers in the tree. You can use 'git-diff' to locate
175 the markers (<<<<<<) and make edits to resolve the conflict. For each
176 file you edit, you need to tell git that the conflict has been resolved,
177 typically this would be done with
178
179
180 git add <filename>
181
182
183 After resolving the conflict manually and updating the index with the
184 desired resolution, you can continue the rebasing process with
185
186
187 git rebase --continue
188
189
190 Alternatively, you can undo the 'git-rebase' with
191
192
193 git rebase --abort
194
195 CONFIGURATION
196 -------------
197
198 rebase.stat::
199 Whether to show a diffstat of what changed upstream since the last
200 rebase. False by default.
201
202 OPTIONS
203 -------
204 <newbase>::
205 Starting point at which to create the new commits. If the
206 --onto option is not specified, the starting point is
207 <upstream>. May be any valid commit, and not just an
208 existing branch name.
209
210 <upstream>::
211 Upstream branch to compare against. May be any valid commit,
212 not just an existing branch name.
213
214 <branch>::
215 Working branch; defaults to HEAD.
216
217 --continue::
218 Restart the rebasing process after having resolved a merge conflict.
219
220 --abort::
221 Restore the original branch and abort the rebase operation.
222
223 --skip::
224 Restart the rebasing process by skipping the current patch.
225
226 -m::
227 --merge::
228 Use merging strategies to rebase. When the recursive (default) merge
229 strategy is used, this allows rebase to be aware of renames on the
230 upstream side.
231
232 -s <strategy>::
233 --strategy=<strategy>::
234 Use the given merge strategy.
235 If there is no `-s` option, a built-in list of strategies
236 is used instead ('git-merge-recursive' when merging a single
237 head, 'git-merge-octopus' otherwise). This implies --merge.
238
239 -q::
240 --quiet::
241 Be quiet. Implies --no-stat.
242
243 -v::
244 --verbose::
245 Be verbose. Implies --stat.
246
247 --stat::
248 Show a diffstat of what changed upstream since the last rebase. The
249 diffstat is also controlled by the configuration option rebase.stat.
250
251 -n::
252 --no-stat::
253 Do not show a diffstat as part of the rebase process.
254
255 --no-verify::
256 This option bypasses the pre-rebase hook. See also linkgit:githooks[5].
257
258 -C<n>::
259 Ensure at least <n> lines of surrounding context match before
260 and after each change. When fewer lines of surrounding
261 context exist they all must match. By default no context is
262 ever ignored.
263
264 -f::
265 --force-rebase::
266 Force the rebase even if the current branch is a descendant
267 of the commit you are rebasing onto. Normally the command will
268 exit with the message "Current branch is up to date" in such a
269 situation.
270
271 --whitespace=<option>::
272 This flag is passed to the 'git-apply' program
273 (see linkgit:git-apply[1]) that applies the patch.
274 Incompatible with the --interactive option.
275
276 --committer-date-is-author-date::
277 --ignore-date::
278 These flags are passed to 'git-am' to easily change the dates
279 of the rebased commits (see linkgit:git-am[1]).
280
281 -i::
282 --interactive::
283 Make a list of the commits which are about to be rebased. Let the
284 user edit that list before rebasing. This mode can also be used to
285 split commits (see SPLITTING COMMITS below).
286
287 -p::
288 --preserve-merges::
289 Instead of ignoring merges, try to recreate them.
290
291 --root::
292 Rebase all commits reachable from <branch>, instead of
293 limiting them with an <upstream>. This allows you to rebase
294 the root commit(s) on a branch. Must be used with --onto, and
295 will skip changes already contained in <newbase> (instead of
296 <upstream>). When used together with --preserve-merges, 'all'
297 root commits will be rewritten to have <newbase> as parent
298 instead.
299
300 include::merge-strategies.txt[]
301
302 NOTES
303 -----
304
305 You should understand the implications of using 'git-rebase' on a
306 repository that you share. See also RECOVERING FROM UPSTREAM REBASE
307 below.
308
309 When the git-rebase command is run, it will first execute a "pre-rebase"
310 hook if one exists. You can use this hook to do sanity checks and
311 reject the rebase if it isn't appropriate. Please see the template
312 pre-rebase hook script for an example.
313
314 Upon completion, <branch> will be the current branch.
315
316 INTERACTIVE MODE
317 ----------------
318
319 Rebasing interactively means that you have a chance to edit the commits
320 which are rebased. You can reorder the commits, and you can
321 remove them (weeding out bad or otherwise unwanted patches).
322
323 The interactive mode is meant for this type of workflow:
324
325 1. have a wonderful idea
326 2. hack on the code
327 3. prepare a series for submission
328 4. submit
329
330 where point 2. consists of several instances of
331
332 a. regular use
333 1. finish something worthy of a commit
334 2. commit
335 b. independent fixup
336 1. realize that something does not work
337 2. fix that
338 3. commit it
339
340 Sometimes the thing fixed in b.2. cannot be amended to the not-quite
341 perfect commit it fixes, because that commit is buried deeply in a
342 patch series. That is exactly what interactive rebase is for: use it
343 after plenty of "a"s and "b"s, by rearranging and editing
344 commits, and squashing multiple commits into one.
345
346 Start it with the last commit you want to retain as-is:
347
348 git rebase -i <after-this-commit>
349
350 An editor will be fired up with all the commits in your current branch
351 (ignoring merge commits), which come after the given commit. You can
352 reorder the commits in this list to your heart's content, and you can
353 remove them. The list looks more or less like this:
354
355 -------------------------------------------
356 pick deadbee The oneline of this commit
357 pick fa1afe1 The oneline of the next commit
358 ...
359 -------------------------------------------
360
361 The oneline descriptions are purely for your pleasure; 'git-rebase' will
362 not look at them but at the commit names ("deadbee" and "fa1afe1" in this
363 example), so do not delete or edit the names.
364
365 By replacing the command "pick" with the command "edit", you can tell
366 'git-rebase' to stop after applying that commit, so that you can edit
367 the files and/or the commit message, amend the commit, and continue
368 rebasing.
369
370 If you want to fold two or more commits into one, replace the command
371 "pick" with "squash" for the second and subsequent commit. If the
372 commits had different authors, it will attribute the squashed commit to
373 the author of the first commit.
374
375 In both cases, or when a "pick" does not succeed (because of merge
376 errors), the loop will stop to let you fix things, and you can continue
377 the loop with `git rebase --continue`.
378
379 For example, if you want to reorder the last 5 commits, such that what
380 was HEAD~4 becomes the new HEAD. To achieve that, you would call
381 'git-rebase' like this:
382
383 ----------------------
384 $ git rebase -i HEAD~5
385 ----------------------
386
387 And move the first patch to the end of the list.
388
389 You might want to preserve merges, if you have a history like this:
390
391 ------------------
392 X
393 \
394 A---M---B
395 /
396 ---o---O---P---Q
397 ------------------
398
399 Suppose you want to rebase the side branch starting at "A" to "Q". Make
400 sure that the current HEAD is "B", and call
401
402 -----------------------------
403 $ git rebase -i -p --onto Q O
404 -----------------------------
405
406
407 SPLITTING COMMITS
408 -----------------
409
410 In interactive mode, you can mark commits with the action "edit". However,
411 this does not necessarily mean that 'git-rebase' expects the result of this
412 edit to be exactly one commit. Indeed, you can undo the commit, or you can
413 add other commits. This can be used to split a commit into two:
414
415 - Start an interactive rebase with `git rebase -i <commit>^`, where
416 <commit> is the commit you want to split. In fact, any commit range
417 will do, as long as it contains that commit.
418
419 - Mark the commit you want to split with the action "edit".
420
421 - When it comes to editing that commit, execute `git reset HEAD^`. The
422 effect is that the HEAD is rewound by one, and the index follows suit.
423 However, the working tree stays the same.
424
425 - Now add the changes to the index that you want to have in the first
426 commit. You can use `git add` (possibly interactively) or
427 'git-gui' (or both) to do that.
428
429 - Commit the now-current index with whatever commit message is appropriate
430 now.
431
432 - Repeat the last two steps until your working tree is clean.
433
434 - Continue the rebase with `git rebase --continue`.
435
436 If you are not absolutely sure that the intermediate revisions are
437 consistent (they compile, pass the testsuite, etc.) you should use
438 'git-stash' to stash away the not-yet-committed changes
439 after each commit, test, and amend the commit if fixes are necessary.
440
441
442 RECOVERING FROM UPSTREAM REBASE
443 -------------------------------
444
445 Rebasing (or any other form of rewriting) a branch that others have
446 based work on is a bad idea: anyone downstream of it is forced to
447 manually fix their history. This section explains how to do the fix
448 from the downstream's point of view. The real fix, however, would be
449 to avoid rebasing the upstream in the first place.
450
451 To illustrate, suppose you are in a situation where someone develops a
452 'subsystem' branch, and you are working on a 'topic' that is dependent
453 on this 'subsystem'. You might end up with a history like the
454 following:
455
456 ------------
457 o---o---o---o---o---o---o---o---o master
458 \
459 o---o---o---o---o subsystem
460 \
461 *---*---* topic
462 ------------
463
464 If 'subsystem' is rebased against 'master', the following happens:
465
466 ------------
467 o---o---o---o---o---o---o---o master
468 \ \
469 o---o---o---o---o o'--o'--o'--o'--o' subsystem
470 \
471 *---*---* topic
472 ------------
473
474 If you now continue development as usual, and eventually merge 'topic'
475 to 'subsystem', the commits from 'subsystem' will remain duplicated forever:
476
477 ------------
478 o---o---o---o---o---o---o---o master
479 \ \
480 o---o---o---o---o o'--o'--o'--o'--o'--M subsystem
481 \ /
482 *---*---*-..........-*--* topic
483 ------------
484
485 Such duplicates are generally frowned upon because they clutter up
486 history, making it harder to follow. To clean things up, you need to
487 transplant the commits on 'topic' to the new 'subsystem' tip, i.e.,
488 rebase 'topic'. This becomes a ripple effect: anyone downstream from
489 'topic' is forced to rebase too, and so on!
490
491 There are two kinds of fixes, discussed in the following subsections:
492
493 Easy case: The changes are literally the same.::
494
495 This happens if the 'subsystem' rebase was a simple rebase and
496 had no conflicts.
497
498 Hard case: The changes are not the same.::
499
500 This happens if the 'subsystem' rebase had conflicts, or used
501 `\--interactive` to omit, edit, or squash commits; or if the
502 upstream used one of `commit \--amend`, `reset`, or
503 `filter-branch`.
504
505
506 The easy case
507 ~~~~~~~~~~~~~
508
509 Only works if the changes (patch IDs based on the diff contents) on
510 'subsystem' are literally the same before and after the rebase
511 'subsystem' did.
512
513 In that case, the fix is easy because 'git-rebase' knows to skip
514 changes that are already present in the new upstream. So if you say
515 (assuming you're on 'topic')
516 ------------
517 $ git rebase subsystem
518 ------------
519 you will end up with the fixed history
520 ------------
521 o---o---o---o---o---o---o---o master
522 \
523 o'--o'--o'--o'--o' subsystem
524 \
525 *---*---* topic
526 ------------
527
528
529 The hard case
530 ~~~~~~~~~~~~~
531
532 Things get more complicated if the 'subsystem' changes do not exactly
533 correspond to the ones before the rebase.
534
535 NOTE: While an "easy case recovery" sometimes appears to be successful
536 even in the hard case, it may have unintended consequences. For
537 example, a commit that was removed via `git rebase
538 \--interactive` will be **resurrected**!
539
540 The idea is to manually tell 'git-rebase' "where the old 'subsystem'
541 ended and your 'topic' began", that is, what the old merge-base
542 between them was. You will have to find a way to name the last commit
543 of the old 'subsystem', for example:
544
545 * With the 'subsystem' reflog: after 'git-fetch', the old tip of
546 'subsystem' is at `subsystem@\{1}`. Subsequent fetches will
547 increase the number. (See linkgit:git-reflog[1].)
548
549 * Relative to the tip of 'topic': knowing that your 'topic' has three
550 commits, the old tip of 'subsystem' must be `topic~3`.
551
552 You can then transplant the old `subsystem..topic` to the new tip by
553 saying (for the reflog case, and assuming you are on 'topic' already):
554 ------------
555 $ git rebase --onto subsystem subsystem@{1}
556 ------------
557
558 The ripple effect of a "hard case" recovery is especially bad:
559 'everyone' downstream from 'topic' will now have to perform a "hard
560 case" recovery too!
561
562
563 Authors
564 ------
565 Written by Junio C Hamano <gitster@pobox.com> and
566 Johannes E. Schindelin <johannes.schindelin@gmx.de>
567
568 Documentation
569 --------------
570 Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
571
572 GIT
573 ---
574 Part of the linkgit:git[1] suite