Merge branch 'ag/userdiff-go-funcname'
[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::rebase-config.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 --allow-empty-message::
248 By default, rebasing commits with an empty message will fail.
249 This option overrides that behavior, allowing commits with empty
250 messages to be rebased.
251
252 --skip::
253 Restart the rebasing process by skipping the current patch.
254
255 --edit-todo::
256 Edit the todo list during an interactive rebase.
257
258 --show-current-patch::
259 Show the current patch in an interactive rebase or when rebase
260 is stopped because of conflicts. This is the equivalent of
261 `git show REBASE_HEAD`.
262
263 -m::
264 --merge::
265 Use merging strategies to rebase. When the recursive (default) merge
266 strategy is used, this allows rebase to be aware of renames on the
267 upstream side.
268 +
269 Note that a rebase merge works by replaying each commit from the working
270 branch on top of the <upstream> branch. Because of this, when a merge
271 conflict happens, the side reported as 'ours' is the so-far rebased
272 series, starting with <upstream>, and 'theirs' is the working branch. In
273 other words, the sides are swapped.
274
275 -s <strategy>::
276 --strategy=<strategy>::
277 Use the given merge strategy.
278 If there is no `-s` option 'git merge-recursive' is used
279 instead. This implies --merge.
280 +
281 Because 'git rebase' replays each commit from the working branch
282 on top of the <upstream> branch using the given strategy, using
283 the 'ours' strategy simply discards all patches from the <branch>,
284 which makes little sense.
285
286 -X <strategy-option>::
287 --strategy-option=<strategy-option>::
288 Pass the <strategy-option> through to the merge strategy.
289 This implies `--merge` and, if no strategy has been
290 specified, `-s recursive`. Note the reversal of 'ours' and
291 'theirs' as noted above for the `-m` option.
292
293 -S[<keyid>]::
294 --gpg-sign[=<keyid>]::
295 GPG-sign commits. The `keyid` argument is optional and
296 defaults to the committer identity; if specified, it must be
297 stuck to the option without a space.
298
299 -q::
300 --quiet::
301 Be quiet. Implies --no-stat.
302
303 -v::
304 --verbose::
305 Be verbose. Implies --stat.
306
307 --stat::
308 Show a diffstat of what changed upstream since the last rebase. The
309 diffstat is also controlled by the configuration option rebase.stat.
310
311 -n::
312 --no-stat::
313 Do not show a diffstat as part of the rebase process.
314
315 --no-verify::
316 This option bypasses the pre-rebase hook. See also linkgit:githooks[5].
317
318 --verify::
319 Allows the pre-rebase hook to run, which is the default. This option can
320 be used to override --no-verify. See also linkgit:githooks[5].
321
322 -C<n>::
323 Ensure at least <n> lines of surrounding context match before
324 and after each change. When fewer lines of surrounding
325 context exist they all must match. By default no context is
326 ever ignored.
327
328 -f::
329 --force-rebase::
330 Force a rebase even if the current branch is up to date and
331 the command without `--force` would return without doing anything.
332 +
333 You may find this (or --no-ff with an interactive rebase) helpful after
334 reverting a topic branch merge, as this option recreates the topic branch with
335 fresh commits so it can be remerged successfully without needing to "revert
336 the reversion" (see the
337 link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for details).
338
339 --fork-point::
340 --no-fork-point::
341 Use reflog to find a better common ancestor between <upstream>
342 and <branch> when calculating which commits have been
343 introduced by <branch>.
344 +
345 When --fork-point is active, 'fork_point' will be used instead of
346 <upstream> to calculate the set of commits to rebase, where
347 'fork_point' is the result of `git merge-base --fork-point <upstream>
348 <branch>` command (see linkgit:git-merge-base[1]). If 'fork_point'
349 ends up being empty, the <upstream> will be used as a fallback.
350 +
351 If either <upstream> or --root is given on the command line, then the
352 default is `--no-fork-point`, otherwise the default is `--fork-point`.
353
354 --ignore-whitespace::
355 --whitespace=<option>::
356 These flag are passed to the 'git apply' program
357 (see linkgit:git-apply[1]) that applies the patch.
358 Incompatible with the --interactive option.
359
360 --committer-date-is-author-date::
361 --ignore-date::
362 These flags are passed to 'git am' to easily change the dates
363 of the rebased commits (see linkgit:git-am[1]).
364 Incompatible with the --interactive option.
365
366 --signoff::
367 This flag is passed to 'git am' to sign off all the rebased
368 commits (see linkgit:git-am[1]). Incompatible with the
369 --interactive option.
370
371 -i::
372 --interactive::
373 Make a list of the commits which are about to be rebased. Let the
374 user edit that list before rebasing. This mode can also be used to
375 split commits (see SPLITTING COMMITS below).
376 +
377 The commit list format can be changed by setting the configuration option
378 rebase.instructionFormat. A customized instruction format will automatically
379 have the long commit hash prepended to the format.
380
381 -p::
382 --preserve-merges::
383 Recreate merge commits instead of flattening the history by replaying
384 commits a merge commit introduces. Merge conflict resolutions or manual
385 amendments to merge commits are not preserved.
386 +
387 This uses the `--interactive` machinery internally, but combining it
388 with the `--interactive` option explicitly is generally not a good
389 idea unless you know what you are doing (see BUGS below).
390
391 -x <cmd>::
392 --exec <cmd>::
393 Append "exec <cmd>" after each line creating a commit in the
394 final history. <cmd> will be interpreted as one or more shell
395 commands.
396 +
397 You may execute several commands by either using one instance of `--exec`
398 with several commands:
399 +
400 git rebase -i --exec "cmd1 && cmd2 && ..."
401 +
402 or by giving more than one `--exec`:
403 +
404 git rebase -i --exec "cmd1" --exec "cmd2" --exec ...
405 +
406 If `--autosquash` is used, "exec" lines will not be appended for
407 the intermediate commits, and will only appear at the end of each
408 squash/fixup series.
409 +
410 This uses the `--interactive` machinery internally, but it can be run
411 without an explicit `--interactive`.
412
413 --root::
414 Rebase all commits reachable from <branch>, instead of
415 limiting them with an <upstream>. This allows you to rebase
416 the root commit(s) on a branch. When used with --onto, it
417 will skip changes already contained in <newbase> (instead of
418 <upstream>) whereas without --onto it will operate on every change.
419 When used together with both --onto and --preserve-merges,
420 'all' root commits will be rewritten to have <newbase> as parent
421 instead.
422
423 --autosquash::
424 --no-autosquash::
425 When the commit log message begins with "squash! ..." (or
426 "fixup! ..."), and there is already a commit in the todo list that
427 matches the same `...`, automatically modify the todo list of rebase
428 -i so that the commit marked for squashing comes right after the
429 commit to be modified, and change the action of the moved commit
430 from `pick` to `squash` (or `fixup`). A commit matches the `...` if
431 the commit subject matches, or if the `...` refers to the commit's
432 hash. As a fall-back, partial matches of the commit subject work,
433 too. The recommended way to create fixup/squash commits is by using
434 the `--fixup`/`--squash` options of linkgit:git-commit[1].
435 +
436 This option is only valid when the `--interactive` option is used.
437 +
438 If the `--autosquash` option is enabled by default using the
439 configuration variable `rebase.autoSquash`, this option can be
440 used to override and disable this setting.
441
442 --autostash::
443 --no-autostash::
444 Automatically create a temporary stash entry before the operation
445 begins, and apply it after the operation ends. This means
446 that you can run rebase on a dirty worktree. However, use
447 with care: the final stash application after a successful
448 rebase might result in non-trivial conflicts.
449
450 --no-ff::
451 With --interactive, cherry-pick all rebased commits instead of
452 fast-forwarding over the unchanged ones. This ensures that the
453 entire history of the rebased branch is composed of new commits.
454 +
455 Without --interactive, this is a synonym for --force-rebase.
456 +
457 You may find this helpful after reverting a topic branch merge, as this option
458 recreates the topic branch with fresh commits so it can be remerged
459 successfully without needing to "revert the reversion" (see the
460 link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for details).
461
462 include::merge-strategies.txt[]
463
464 NOTES
465 -----
466
467 You should understand the implications of using 'git rebase' on a
468 repository that you share. See also RECOVERING FROM UPSTREAM REBASE
469 below.
470
471 When the git-rebase command is run, it will first execute a "pre-rebase"
472 hook if one exists. You can use this hook to do sanity checks and
473 reject the rebase if it isn't appropriate. Please see the template
474 pre-rebase hook script for an example.
475
476 Upon completion, <branch> will be the current branch.
477
478 INTERACTIVE MODE
479 ----------------
480
481 Rebasing interactively means that you have a chance to edit the commits
482 which are rebased. You can reorder the commits, and you can
483 remove them (weeding out bad or otherwise unwanted patches).
484
485 The interactive mode is meant for this type of workflow:
486
487 1. have a wonderful idea
488 2. hack on the code
489 3. prepare a series for submission
490 4. submit
491
492 where point 2. consists of several instances of
493
494 a) regular use
495
496 1. finish something worthy of a commit
497 2. commit
498
499 b) independent fixup
500
501 1. realize that something does not work
502 2. fix that
503 3. commit it
504
505 Sometimes the thing fixed in b.2. cannot be amended to the not-quite
506 perfect commit it fixes, because that commit is buried deeply in a
507 patch series. That is exactly what interactive rebase is for: use it
508 after plenty of "a"s and "b"s, by rearranging and editing
509 commits, and squashing multiple commits into one.
510
511 Start it with the last commit you want to retain as-is:
512
513 git rebase -i <after-this-commit>
514
515 An editor will be fired up with all the commits in your current branch
516 (ignoring merge commits), which come after the given commit. You can
517 reorder the commits in this list to your heart's content, and you can
518 remove them. The list looks more or less like this:
519
520 -------------------------------------------
521 pick deadbee The oneline of this commit
522 pick fa1afe1 The oneline of the next commit
523 ...
524 -------------------------------------------
525
526 The oneline descriptions are purely for your pleasure; 'git rebase' will
527 not look at them but at the commit names ("deadbee" and "fa1afe1" in this
528 example), so do not delete or edit the names.
529
530 By replacing the command "pick" with the command "edit", you can tell
531 'git rebase' to stop after applying that commit, so that you can edit
532 the files and/or the commit message, amend the commit, and continue
533 rebasing.
534
535 If you just want to edit the commit message for a commit, replace the
536 command "pick" with the command "reword".
537
538 To drop a commit, replace the command "pick" with "drop", or just
539 delete the matching line.
540
541 If you want to fold two or more commits into one, replace the command
542 "pick" for the second and subsequent commits with "squash" or "fixup".
543 If the commits had different authors, the folded commit will be
544 attributed to the author of the first commit. The suggested commit
545 message for the folded commit is the concatenation of the commit
546 messages of the first commit and of those with the "squash" command,
547 but omits the commit messages of commits with the "fixup" command.
548
549 'git rebase' will stop when "pick" has been replaced with "edit" or
550 when a command fails due to merge errors. When you are done editing
551 and/or resolving conflicts you can continue with `git rebase --continue`.
552
553 For example, if you want to reorder the last 5 commits, such that what
554 was HEAD~4 becomes the new HEAD. To achieve that, you would call
555 'git rebase' like this:
556
557 ----------------------
558 $ git rebase -i HEAD~5
559 ----------------------
560
561 And move the first patch to the end of the list.
562
563 You might want to preserve merges, if you have a history like this:
564
565 ------------------
566 X
567 \
568 A---M---B
569 /
570 ---o---O---P---Q
571 ------------------
572
573 Suppose you want to rebase the side branch starting at "A" to "Q". Make
574 sure that the current HEAD is "B", and call
575
576 -----------------------------
577 $ git rebase -i -p --onto Q O
578 -----------------------------
579
580 Reordering and editing commits usually creates untested intermediate
581 steps. You may want to check that your history editing did not break
582 anything by running a test, or at least recompiling at intermediate
583 points in history by using the "exec" command (shortcut "x"). You may
584 do so by creating a todo list like this one:
585
586 -------------------------------------------
587 pick deadbee Implement feature XXX
588 fixup f1a5c00 Fix to feature XXX
589 exec make
590 pick c0ffeee The oneline of the next commit
591 edit deadbab The oneline of the commit after
592 exec cd subdir; make test
593 ...
594 -------------------------------------------
595
596 The interactive rebase will stop when a command fails (i.e. exits with
597 non-0 status) to give you an opportunity to fix the problem. You can
598 continue with `git rebase --continue`.
599
600 The "exec" command launches the command in a shell (the one specified
601 in `$SHELL`, or the default shell if `$SHELL` is not set), so you can
602 use shell features (like "cd", ">", ";" ...). The command is run from
603 the root of the working tree.
604
605 ----------------------------------
606 $ git rebase -i --exec "make test"
607 ----------------------------------
608
609 This command lets you check that intermediate commits are compilable.
610 The todo list becomes like that:
611
612 --------------------
613 pick 5928aea one
614 exec make test
615 pick 04d0fda two
616 exec make test
617 pick ba46169 three
618 exec make test
619 pick f4593f9 four
620 exec make test
621 --------------------
622
623 SPLITTING COMMITS
624 -----------------
625
626 In interactive mode, you can mark commits with the action "edit". However,
627 this does not necessarily mean that 'git rebase' expects the result of this
628 edit to be exactly one commit. Indeed, you can undo the commit, or you can
629 add other commits. This can be used to split a commit into two:
630
631 - Start an interactive rebase with `git rebase -i <commit>^`, where
632 <commit> is the commit you want to split. In fact, any commit range
633 will do, as long as it contains that commit.
634
635 - Mark the commit you want to split with the action "edit".
636
637 - When it comes to editing that commit, execute `git reset HEAD^`. The
638 effect is that the HEAD is rewound by one, and the index follows suit.
639 However, the working tree stays the same.
640
641 - Now add the changes to the index that you want to have in the first
642 commit. You can use `git add` (possibly interactively) or
643 'git gui' (or both) to do that.
644
645 - Commit the now-current index with whatever commit message is appropriate
646 now.
647
648 - Repeat the last two steps until your working tree is clean.
649
650 - Continue the rebase with `git rebase --continue`.
651
652 If you are not absolutely sure that the intermediate revisions are
653 consistent (they compile, pass the testsuite, etc.) you should use
654 'git stash' to stash away the not-yet-committed changes
655 after each commit, test, and amend the commit if fixes are necessary.
656
657
658 RECOVERING FROM UPSTREAM REBASE
659 -------------------------------
660
661 Rebasing (or any other form of rewriting) a branch that others have
662 based work on is a bad idea: anyone downstream of it is forced to
663 manually fix their history. This section explains how to do the fix
664 from the downstream's point of view. The real fix, however, would be
665 to avoid rebasing the upstream in the first place.
666
667 To illustrate, suppose you are in a situation where someone develops a
668 'subsystem' branch, and you are working on a 'topic' that is dependent
669 on this 'subsystem'. You might end up with a history like the
670 following:
671
672 ------------
673 o---o---o---o---o---o---o---o master
674 \
675 o---o---o---o---o subsystem
676 \
677 *---*---* topic
678 ------------
679
680 If 'subsystem' is rebased against 'master', the following happens:
681
682 ------------
683 o---o---o---o---o---o---o---o master
684 \ \
685 o---o---o---o---o o'--o'--o'--o'--o' subsystem
686 \
687 *---*---* topic
688 ------------
689
690 If you now continue development as usual, and eventually merge 'topic'
691 to 'subsystem', the commits from 'subsystem' will remain duplicated forever:
692
693 ------------
694 o---o---o---o---o---o---o---o master
695 \ \
696 o---o---o---o---o o'--o'--o'--o'--o'--M subsystem
697 \ /
698 *---*---*-..........-*--* topic
699 ------------
700
701 Such duplicates are generally frowned upon because they clutter up
702 history, making it harder to follow. To clean things up, you need to
703 transplant the commits on 'topic' to the new 'subsystem' tip, i.e.,
704 rebase 'topic'. This becomes a ripple effect: anyone downstream from
705 'topic' is forced to rebase too, and so on!
706
707 There are two kinds of fixes, discussed in the following subsections:
708
709 Easy case: The changes are literally the same.::
710
711 This happens if the 'subsystem' rebase was a simple rebase and
712 had no conflicts.
713
714 Hard case: The changes are not the same.::
715
716 This happens if the 'subsystem' rebase had conflicts, or used
717 `--interactive` to omit, edit, squash, or fixup commits; or
718 if the upstream used one of `commit --amend`, `reset`, or
719 `filter-branch`.
720
721
722 The easy case
723 ~~~~~~~~~~~~~
724
725 Only works if the changes (patch IDs based on the diff contents) on
726 'subsystem' are literally the same before and after the rebase
727 'subsystem' did.
728
729 In that case, the fix is easy because 'git rebase' knows to skip
730 changes that are already present in the new upstream. So if you say
731 (assuming you're on 'topic')
732 ------------
733 $ git rebase subsystem
734 ------------
735 you will end up with the fixed history
736 ------------
737 o---o---o---o---o---o---o---o master
738 \
739 o'--o'--o'--o'--o' subsystem
740 \
741 *---*---* topic
742 ------------
743
744
745 The hard case
746 ~~~~~~~~~~~~~
747
748 Things get more complicated if the 'subsystem' changes do not exactly
749 correspond to the ones before the rebase.
750
751 NOTE: While an "easy case recovery" sometimes appears to be successful
752 even in the hard case, it may have unintended consequences. For
753 example, a commit that was removed via `git rebase
754 --interactive` will be **resurrected**!
755
756 The idea is to manually tell 'git rebase' "where the old 'subsystem'
757 ended and your 'topic' began", that is, what the old merge-base
758 between them was. You will have to find a way to name the last commit
759 of the old 'subsystem', for example:
760
761 * With the 'subsystem' reflog: after 'git fetch', the old tip of
762 'subsystem' is at `subsystem@{1}`. Subsequent fetches will
763 increase the number. (See linkgit:git-reflog[1].)
764
765 * Relative to the tip of 'topic': knowing that your 'topic' has three
766 commits, the old tip of 'subsystem' must be `topic~3`.
767
768 You can then transplant the old `subsystem..topic` to the new tip by
769 saying (for the reflog case, and assuming you are on 'topic' already):
770 ------------
771 $ git rebase --onto subsystem subsystem@{1}
772 ------------
773
774 The ripple effect of a "hard case" recovery is especially bad:
775 'everyone' downstream from 'topic' will now have to perform a "hard
776 case" recovery too!
777
778 BUGS
779 ----
780 The todo list presented by `--preserve-merges --interactive` does not
781 represent the topology of the revision graph. Editing commits and
782 rewording their commit messages should work fine, but attempts to
783 reorder commits tend to produce counterintuitive results.
784
785 For example, an attempt to rearrange
786 ------------
787 1 --- 2 --- 3 --- 4 --- 5
788 ------------
789 to
790 ------------
791 1 --- 2 --- 4 --- 3 --- 5
792 ------------
793 by moving the "pick 4" line will result in the following history:
794 ------------
795 3
796 /
797 1 --- 2 --- 4 --- 5
798 ------------
799
800 GIT
801 ---
802 Part of the linkgit:git[1] suite