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215a7ad1 JH |
1 | git-rebase(1) |
2 | ============= | |
7fc9d69f JH |
3 | |
4 | NAME | |
5 | ---- | |
c3f0baac | 6 | git-rebase - Forward-port local commits to the updated upstream head |
7fc9d69f JH |
7 | |
8 | SYNOPSIS | |
9 | -------- | |
e448ff87 | 10 | [verse] |
be496621 TR |
11 | 'git rebase' [-i | --interactive] [options] [--onto <newbase>] |
12 | <upstream> [<branch>] | |
13 | 'git rebase' [-i | --interactive] [options] --onto <newbase> | |
14 | --root [<branch>] | |
15 | ||
b1889c36 | 16 | 'git rebase' --continue | --skip | --abort |
031321c6 | 17 | |
7fc9d69f JH |
18 | DESCRIPTION |
19 | ----------- | |
0b444cdb | 20 | If <branch> is specified, 'git rebase' will perform an automatic |
5ca2db53 SP |
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 | |
be496621 TR |
26 | of commits that would be shown by `git log <upstream>..HEAD` (or |
27 | `git log HEAD`, if --root is specified). | |
5ca2db53 SP |
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 | |
9869099b BG |
31 | `git reset --hard <upstream>` (or <newbase>). ORIG_HEAD is set |
32 | to point at the tip of the branch before the reset. | |
5ca2db53 SP |
33 | |
34 | The commits that were previously saved into the temporary area are | |
ff905462 JK |
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). | |
69a60af5 | 39 | |
031321c6 SE |
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 | |
cc120056 SE |
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 | |
51ef1daa JS |
44 | original <branch> and remove the .git/rebase-apply working files, use the |
45 | command `git rebase --abort` instead. | |
031321c6 | 46 | |
69a60af5 CW |
47 | Assume the following history exists and the current branch is "topic": |
48 | ||
031321c6 | 49 | ------------ |
69a60af5 CW |
50 | A---B---C topic |
51 | / | |
52 | D---E---F---G master | |
031321c6 | 53 | ------------ |
69a60af5 | 54 | |
228382ae | 55 | From this point, the result of either of the following commands: |
69a60af5 | 56 | |
031321c6 | 57 | |
b1889c36 JN |
58 | git rebase master |
59 | git rebase master topic | |
69a60af5 CW |
60 | |
61 | would be: | |
62 | ||
031321c6 | 63 | ------------ |
69a60af5 CW |
64 | A'--B'--C' topic |
65 | / | |
66 | D---E---F---G master | |
031321c6 | 67 | ------------ |
69a60af5 | 68 | |
e52775f4 JN |
69 | The latter form is just a short-hand of `git checkout topic` |
70 | followed by `git rebase master`. | |
69a60af5 | 71 | |
ff905462 JK |
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 | |
b1889c36 | 74 | will be skipped. For example, running `git rebase master` on the |
ff905462 JK |
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 | ||
e52775f4 JN |
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`. | |
69a60af5 | 95 | |
e52775f4 | 96 | First let's assume your 'topic' is based on branch 'next'. |
e2b850b2 | 97 | For example, a feature developed in 'topic' depends on some |
e52775f4 | 98 | functionality which is found in 'next'. |
69a60af5 | 99 | |
031321c6 | 100 | ------------ |
e52775f4 JN |
101 | o---o---o---o---o master |
102 | \ | |
103 | o---o---o---o---o next | |
104 | \ | |
105 | o---o---o topic | |
106 | ------------ | |
107 | ||
e2b850b2 GD |
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: | |
e52775f4 JN |
111 | |
112 | ------------ | |
113 | o---o---o---o---o master | |
114 | | \ | |
115 | | o'--o'--o' topic | |
116 | \ | |
117 | o---o---o---o---o next | |
031321c6 | 118 | ------------ |
7fc9d69f | 119 | |
e52775f4 JN |
120 | We can get this using the following command: |
121 | ||
b1889c36 | 122 | git rebase --onto master next topic |
e52775f4 JN |
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 | ||
b1889c36 | 138 | git rebase --onto master topicA topicB |
e52775f4 JN |
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 | ||
ea81fcc5 SP |
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 | ||
b1889c36 | 161 | git rebase --onto topicA~5 topicA~3 topicA |
ea81fcc5 SP |
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 | ||
0b444cdb TR |
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 | |
031321c6 SE |
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 | ||
d7f078b8 | 180 | git add <filename> |
031321c6 SE |
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 | |
8978d043 | 188 | |
8978d043 | 189 | |
0b444cdb | 190 | Alternatively, you can undo the 'git rebase' with |
8978d043 | 191 | |
031321c6 SE |
192 | |
193 | git rebase --abort | |
8978d043 | 194 | |
a9c3821c TAV |
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 | ||
7fc9d69f JH |
202 | OPTIONS |
203 | ------- | |
69a60af5 CW |
204 | <newbase>:: |
205 | Starting point at which to create the new commits. If the | |
206 | --onto option is not specified, the starting point is | |
ea81fcc5 SP |
207 | <upstream>. May be any valid commit, and not just an |
208 | existing branch name. | |
873c3472 MG |
209 | + |
210 | As a special case, you may use "A...B" as a shortcut for the | |
211 | merge base of A and B if there is exactly one merge base. You can | |
212 | leave out at most one of A and B, in which case it defaults to HEAD. | |
69a60af5 | 213 | |
52a22d1e | 214 | <upstream>:: |
ea81fcc5 SP |
215 | Upstream branch to compare against. May be any valid commit, |
216 | not just an existing branch name. | |
7fc9d69f | 217 | |
228382ae | 218 | <branch>:: |
52a22d1e | 219 | Working branch; defaults to HEAD. |
7fc9d69f | 220 | |
031321c6 SE |
221 | --continue:: |
222 | Restart the rebasing process after having resolved a merge conflict. | |
223 | ||
224 | --abort:: | |
225 | Restore the original branch and abort the rebase operation. | |
226 | ||
58634dbf EW |
227 | --skip:: |
228 | Restart the rebasing process by skipping the current patch. | |
58634dbf | 229 | |
3240240f SB |
230 | -m:: |
231 | --merge:: | |
58634dbf EW |
232 | Use merging strategies to rebase. When the recursive (default) merge |
233 | strategy is used, this allows rebase to be aware of renames on the | |
234 | upstream side. | |
31ddd1ee TR |
235 | + |
236 | Note that a rebase merge works by replaying each commit from the working | |
237 | branch on top of the <upstream> branch. Because of this, when a merge | |
238 | conflict happens, the side reported as 'ours' is the so-far rebased | |
239 | series, starting with <upstream>, and 'theirs' is the working branch. In | |
240 | other words, the sides are swapped. | |
58634dbf | 241 | |
3240240f SB |
242 | -s <strategy>:: |
243 | --strategy=<strategy>:: | |
06f39190 | 244 | Use the given merge strategy. |
0b444cdb | 245 | If there is no `-s` option 'git merge-recursive' is used |
31ddd1ee TR |
246 | instead. This implies --merge. |
247 | + | |
0b444cdb | 248 | Because 'git rebase' replays each commit from the working branch |
31ddd1ee TR |
249 | on top of the <upstream> branch using the given strategy, using |
250 | the 'ours' strategy simply discards all patches from the <branch>, | |
251 | which makes little sense. | |
58634dbf | 252 | |
93ce190c ML |
253 | -X <strategy-option>:: |
254 | --strategy-option=<strategy-option>:: | |
255 | Pass the <strategy-option> through to the merge strategy. | |
256 | This implies `\--merge` and, if no strategy has been | |
257 | specified, `-s recursive`. Note the reversal of 'ours' and | |
258 | 'theirs' as noted in above for the `-m` option. | |
259 | ||
0e987a12 SB |
260 | -q:: |
261 | --quiet:: | |
262 | Be quiet. Implies --no-stat. | |
263 | ||
3240240f SB |
264 | -v:: |
265 | --verbose:: | |
a9c3821c TAV |
266 | Be verbose. Implies --stat. |
267 | ||
268 | --stat:: | |
269 | Show a diffstat of what changed upstream since the last rebase. The | |
270 | diffstat is also controlled by the configuration option rebase.stat. | |
271 | ||
272 | -n:: | |
273 | --no-stat:: | |
274 | Do not show a diffstat as part of the rebase process. | |
b758789c | 275 | |
fd631d58 NS |
276 | --no-verify:: |
277 | This option bypasses the pre-rebase hook. See also linkgit:githooks[5]. | |
278 | ||
67dad687 MT |
279 | -C<n>:: |
280 | Ensure at least <n> lines of surrounding context match before | |
281 | and after each change. When fewer lines of surrounding | |
282 | context exist they all must match. By default no context is | |
283 | ever ignored. | |
284 | ||
5e75d56f MB |
285 | -f:: |
286 | --force-rebase:: | |
287 | Force the rebase even if the current branch is a descendant | |
b4995494 | 288 | of the commit you are rebasing onto. Normally non-interactive rebase will |
5e75d56f MB |
289 | exit with the message "Current branch is up to date" in such a |
290 | situation. | |
b4995494 MB |
291 | Incompatible with the --interactive option. |
292 | + | |
293 | You may find this (or --no-ff with an interactive rebase) helpful after | |
294 | reverting a topic branch merge, as this option recreates the topic branch with | |
295 | fresh commits so it can be remerged successfully without needing to "revert | |
296 | the reversion" (see the | |
297 | link:howto/revert-a-faulty-merge.txt[revert-a-faulty-merge How-To] for details). | |
5e75d56f | 298 | |
86c91f91 | 299 | --ignore-whitespace:: |
749485f6 | 300 | --whitespace=<option>:: |
0b444cdb | 301 | These flag are passed to the 'git apply' program |
5162e697 | 302 | (see linkgit:git-apply[1]) that applies the patch. |
7fe54385 | 303 | Incompatible with the --interactive option. |
059f446d | 304 | |
570ccad3 MB |
305 | --committer-date-is-author-date:: |
306 | --ignore-date:: | |
0b444cdb | 307 | These flags are passed to 'git am' to easily change the dates |
570ccad3 | 308 | of the rebased commits (see linkgit:git-am[1]). |
56a05720 | 309 | Incompatible with the --interactive option. |
570ccad3 | 310 | |
3240240f SB |
311 | -i:: |
312 | --interactive:: | |
1b1dce4b | 313 | Make a list of the commits which are about to be rebased. Let the |
f0fd889d JS |
314 | user edit that list before rebasing. This mode can also be used to |
315 | split commits (see SPLITTING COMMITS below). | |
1b1dce4b | 316 | |
3240240f SB |
317 | -p:: |
318 | --preserve-merges:: | |
f8cca019 | 319 | Instead of ignoring merges, try to recreate them. |
cddb42d2 JN |
320 | + |
321 | This uses the `--interactive` machinery internally, but combining it | |
322 | with the `--interactive` option explicitly is generally not a good | |
323 | idea unless you know what you are doing (see BUGS below). | |
324 | ||
f09c9b8c | 325 | |
be496621 TR |
326 | --root:: |
327 | Rebase all commits reachable from <branch>, instead of | |
328 | limiting them with an <upstream>. This allows you to rebase | |
329 | the root commit(s) on a branch. Must be used with --onto, and | |
330 | will skip changes already contained in <newbase> (instead of | |
331 | <upstream>). When used together with --preserve-merges, 'all' | |
332 | root commits will be rewritten to have <newbase> as parent | |
333 | instead. | |
334 | ||
f59baa50 NS |
335 | --autosquash:: |
336 | When the commit log message begins with "squash! ..." (or | |
337 | "fixup! ..."), and there is a commit whose title begins with | |
338 | the same ..., automatically modify the todo list of rebase -i | |
42cfcd20 | 339 | so that the commit marked for squashing comes right after the |
f59baa50 NS |
340 | commit to be modified, and change the action of the moved |
341 | commit from `pick` to `squash` (or `fixup`). | |
342 | + | |
b4995494 MB |
343 | This option is only valid when the '--interactive' option is used. |
344 | ||
345 | --no-ff:: | |
346 | With --interactive, cherry-pick all rebased commits instead of | |
347 | fast-forwarding over the unchanged ones. This ensures that the | |
348 | entire history of the rebased branch is composed of new commits. | |
349 | + | |
350 | Without --interactive, this is a synonym for --force-rebase. | |
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.txt[revert-a-faulty-merge How-To] for details). | |
f59baa50 | 356 | |
58634dbf EW |
357 | include::merge-strategies.txt[] |
358 | ||
031321c6 SE |
359 | NOTES |
360 | ----- | |
90d1c08e | 361 | |
0b444cdb | 362 | You should understand the implications of using 'git rebase' on a |
90d1c08e TR |
363 | repository that you share. See also RECOVERING FROM UPSTREAM REBASE |
364 | below. | |
031321c6 | 365 | |
467c0197 | 366 | When the git-rebase command is run, it will first execute a "pre-rebase" |
031321c6 SE |
367 | hook if one exists. You can use this hook to do sanity checks and |
368 | reject the rebase if it isn't appropriate. Please see the template | |
369 | pre-rebase hook script for an example. | |
370 | ||
702088af | 371 | Upon completion, <branch> will be the current branch. |
031321c6 | 372 | |
1b1dce4b JS |
373 | INTERACTIVE MODE |
374 | ---------------- | |
375 | ||
376 | Rebasing interactively means that you have a chance to edit the commits | |
377 | which are rebased. You can reorder the commits, and you can | |
378 | remove them (weeding out bad or otherwise unwanted patches). | |
379 | ||
380 | The interactive mode is meant for this type of workflow: | |
381 | ||
382 | 1. have a wonderful idea | |
383 | 2. hack on the code | |
384 | 3. prepare a series for submission | |
385 | 4. submit | |
386 | ||
387 | where point 2. consists of several instances of | |
388 | ||
389 | a. regular use | |
390 | 1. finish something worthy of a commit | |
391 | 2. commit | |
392 | b. independent fixup | |
393 | 1. realize that something does not work | |
394 | 2. fix that | |
395 | 3. commit it | |
396 | ||
397 | Sometimes the thing fixed in b.2. cannot be amended to the not-quite | |
398 | perfect commit it fixes, because that commit is buried deeply in a | |
399 | patch series. That is exactly what interactive rebase is for: use it | |
400 | after plenty of "a"s and "b"s, by rearranging and editing | |
401 | commits, and squashing multiple commits into one. | |
402 | ||
403 | Start it with the last commit you want to retain as-is: | |
404 | ||
405 | git rebase -i <after-this-commit> | |
406 | ||
407 | An editor will be fired up with all the commits in your current branch | |
408 | (ignoring merge commits), which come after the given commit. You can | |
409 | reorder the commits in this list to your heart's content, and you can | |
410 | remove them. The list looks more or less like this: | |
411 | ||
412 | ------------------------------------------- | |
413 | pick deadbee The oneline of this commit | |
414 | pick fa1afe1 The oneline of the next commit | |
415 | ... | |
416 | ------------------------------------------- | |
417 | ||
0b444cdb | 418 | The oneline descriptions are purely for your pleasure; 'git rebase' will |
1b1dce4b JS |
419 | not look at them but at the commit names ("deadbee" and "fa1afe1" in this |
420 | example), so do not delete or edit the names. | |
421 | ||
422 | By replacing the command "pick" with the command "edit", you can tell | |
0b444cdb | 423 | 'git rebase' to stop after applying that commit, so that you can edit |
1b1dce4b JS |
424 | the files and/or the commit message, amend the commit, and continue |
425 | rebasing. | |
426 | ||
6741aa6c BG |
427 | If you just want to edit the commit message for a commit, replace the |
428 | command "pick" with the command "reword". | |
429 | ||
1b1dce4b | 430 | If you want to fold two or more commits into one, replace the command |
0205e72f MH |
431 | "pick" for the second and subsequent commits with "squash" or "fixup". |
432 | If the commits had different authors, the folded commit will be | |
433 | attributed to the author of the first commit. The suggested commit | |
434 | message for the folded commit is the concatenation of the commit | |
435 | messages of the first commit and of those with the "squash" command, | |
436 | but omits the commit messages of commits with the "fixup" command. | |
1b1dce4b | 437 | |
0b444cdb | 438 | 'git rebase' will stop when "pick" has been replaced with "edit" or |
6741aa6c BG |
439 | when a command fails due to merge errors. When you are done editing |
440 | and/or resolving conflicts you can continue with `git rebase --continue`. | |
1b1dce4b JS |
441 | |
442 | For example, if you want to reorder the last 5 commits, such that what | |
443 | was HEAD~4 becomes the new HEAD. To achieve that, you would call | |
0b444cdb | 444 | 'git rebase' like this: |
1b1dce4b JS |
445 | |
446 | ---------------------- | |
447 | $ git rebase -i HEAD~5 | |
448 | ---------------------- | |
449 | ||
450 | And move the first patch to the end of the list. | |
451 | ||
f09c9b8c JS |
452 | You might want to preserve merges, if you have a history like this: |
453 | ||
454 | ------------------ | |
455 | X | |
456 | \ | |
457 | A---M---B | |
458 | / | |
459 | ---o---O---P---Q | |
460 | ------------------ | |
461 | ||
462 | Suppose you want to rebase the side branch starting at "A" to "Q". Make | |
463 | sure that the current HEAD is "B", and call | |
464 | ||
465 | ----------------------------- | |
466 | $ git rebase -i -p --onto Q O | |
467 | ----------------------------- | |
468 | ||
f0fd889d JS |
469 | |
470 | SPLITTING COMMITS | |
471 | ----------------- | |
472 | ||
473 | In interactive mode, you can mark commits with the action "edit". However, | |
0b444cdb | 474 | this does not necessarily mean that 'git rebase' expects the result of this |
f0fd889d JS |
475 | edit to be exactly one commit. Indeed, you can undo the commit, or you can |
476 | add other commits. This can be used to split a commit into two: | |
477 | ||
483bc4f0 | 478 | - Start an interactive rebase with `git rebase -i <commit>^`, where |
f0fd889d JS |
479 | <commit> is the commit you want to split. In fact, any commit range |
480 | will do, as long as it contains that commit. | |
481 | ||
482 | - Mark the commit you want to split with the action "edit". | |
483 | ||
483bc4f0 | 484 | - When it comes to editing that commit, execute `git reset HEAD^`. The |
f0fd889d JS |
485 | effect is that the HEAD is rewound by one, and the index follows suit. |
486 | However, the working tree stays the same. | |
487 | ||
488 | - Now add the changes to the index that you want to have in the first | |
483bc4f0 | 489 | commit. You can use `git add` (possibly interactively) or |
0b444cdb | 490 | 'git gui' (or both) to do that. |
f0fd889d JS |
491 | |
492 | - Commit the now-current index with whatever commit message is appropriate | |
493 | now. | |
494 | ||
495 | - Repeat the last two steps until your working tree is clean. | |
496 | ||
483bc4f0 | 497 | - Continue the rebase with `git rebase --continue`. |
f0fd889d JS |
498 | |
499 | If you are not absolutely sure that the intermediate revisions are | |
500 | consistent (they compile, pass the testsuite, etc.) you should use | |
0b444cdb | 501 | 'git stash' to stash away the not-yet-committed changes |
f0fd889d JS |
502 | after each commit, test, and amend the commit if fixes are necessary. |
503 | ||
504 | ||
90d1c08e TR |
505 | RECOVERING FROM UPSTREAM REBASE |
506 | ------------------------------- | |
507 | ||
508 | Rebasing (or any other form of rewriting) a branch that others have | |
509 | based work on is a bad idea: anyone downstream of it is forced to | |
510 | manually fix their history. This section explains how to do the fix | |
511 | from the downstream's point of view. The real fix, however, would be | |
512 | to avoid rebasing the upstream in the first place. | |
513 | ||
514 | To illustrate, suppose you are in a situation where someone develops a | |
515 | 'subsystem' branch, and you are working on a 'topic' that is dependent | |
516 | on this 'subsystem'. You might end up with a history like the | |
517 | following: | |
518 | ||
519 | ------------ | |
520 | o---o---o---o---o---o---o---o---o master | |
521 | \ | |
522 | o---o---o---o---o subsystem | |
523 | \ | |
524 | *---*---* topic | |
525 | ------------ | |
526 | ||
527 | If 'subsystem' is rebased against 'master', the following happens: | |
528 | ||
529 | ------------ | |
530 | o---o---o---o---o---o---o---o master | |
531 | \ \ | |
532 | o---o---o---o---o o'--o'--o'--o'--o' subsystem | |
533 | \ | |
534 | *---*---* topic | |
535 | ------------ | |
536 | ||
537 | If you now continue development as usual, and eventually merge 'topic' | |
538 | to 'subsystem', the commits from 'subsystem' will remain duplicated forever: | |
539 | ||
540 | ------------ | |
541 | o---o---o---o---o---o---o---o master | |
542 | \ \ | |
543 | o---o---o---o---o o'--o'--o'--o'--o'--M subsystem | |
544 | \ / | |
545 | *---*---*-..........-*--* topic | |
546 | ------------ | |
547 | ||
548 | Such duplicates are generally frowned upon because they clutter up | |
549 | history, making it harder to follow. To clean things up, you need to | |
550 | transplant the commits on 'topic' to the new 'subsystem' tip, i.e., | |
551 | rebase 'topic'. This becomes a ripple effect: anyone downstream from | |
552 | 'topic' is forced to rebase too, and so on! | |
553 | ||
554 | There are two kinds of fixes, discussed in the following subsections: | |
555 | ||
556 | Easy case: The changes are literally the same.:: | |
557 | ||
558 | This happens if the 'subsystem' rebase was a simple rebase and | |
559 | had no conflicts. | |
560 | ||
561 | Hard case: The changes are not the same.:: | |
562 | ||
563 | This happens if the 'subsystem' rebase had conflicts, or used | |
0205e72f MH |
564 | `\--interactive` to omit, edit, squash, or fixup commits; or |
565 | if the upstream used one of `commit \--amend`, `reset`, or | |
90d1c08e TR |
566 | `filter-branch`. |
567 | ||
568 | ||
569 | The easy case | |
570 | ~~~~~~~~~~~~~ | |
571 | ||
572 | Only works if the changes (patch IDs based on the diff contents) on | |
573 | 'subsystem' are literally the same before and after the rebase | |
574 | 'subsystem' did. | |
575 | ||
0b444cdb | 576 | In that case, the fix is easy because 'git rebase' knows to skip |
90d1c08e TR |
577 | changes that are already present in the new upstream. So if you say |
578 | (assuming you're on 'topic') | |
579 | ------------ | |
580 | $ git rebase subsystem | |
581 | ------------ | |
582 | you will end up with the fixed history | |
583 | ------------ | |
584 | o---o---o---o---o---o---o---o master | |
585 | \ | |
586 | o'--o'--o'--o'--o' subsystem | |
587 | \ | |
588 | *---*---* topic | |
589 | ------------ | |
590 | ||
591 | ||
592 | The hard case | |
593 | ~~~~~~~~~~~~~ | |
594 | ||
595 | Things get more complicated if the 'subsystem' changes do not exactly | |
596 | correspond to the ones before the rebase. | |
597 | ||
598 | NOTE: While an "easy case recovery" sometimes appears to be successful | |
599 | even in the hard case, it may have unintended consequences. For | |
600 | example, a commit that was removed via `git rebase | |
601 | \--interactive` will be **resurrected**! | |
602 | ||
0b444cdb | 603 | The idea is to manually tell 'git rebase' "where the old 'subsystem' |
90d1c08e TR |
604 | ended and your 'topic' began", that is, what the old merge-base |
605 | between them was. You will have to find a way to name the last commit | |
606 | of the old 'subsystem', for example: | |
607 | ||
0b444cdb | 608 | * With the 'subsystem' reflog: after 'git fetch', the old tip of |
90d1c08e TR |
609 | 'subsystem' is at `subsystem@\{1}`. Subsequent fetches will |
610 | increase the number. (See linkgit:git-reflog[1].) | |
611 | ||
612 | * Relative to the tip of 'topic': knowing that your 'topic' has three | |
613 | commits, the old tip of 'subsystem' must be `topic~3`. | |
614 | ||
615 | You can then transplant the old `subsystem..topic` to the new tip by | |
616 | saying (for the reflog case, and assuming you are on 'topic' already): | |
617 | ------------ | |
618 | $ git rebase --onto subsystem subsystem@{1} | |
619 | ------------ | |
620 | ||
621 | The ripple effect of a "hard case" recovery is especially bad: | |
622 | 'everyone' downstream from 'topic' will now have to perform a "hard | |
623 | case" recovery too! | |
624 | ||
625 | ||
cddb42d2 JN |
626 | BUGS |
627 | ---- | |
628 | The todo list presented by `--preserve-merges --interactive` does not | |
629 | represent the topology of the revision graph. Editing commits and | |
630 | rewording their commit messages should work fine, but attempts to | |
631 | reorder commits tend to produce counterintuitive results. | |
632 | ||
633 | For example, an attempt to rearrange | |
634 | ------------ | |
635 | 1 --- 2 --- 3 --- 4 --- 5 | |
636 | ------------ | |
637 | to | |
638 | ------------ | |
639 | 1 --- 2 --- 4 --- 3 --- 5 | |
640 | ------------ | |
641 | by moving the "pick 4" line will result in the following history: | |
642 | ------------ | |
643 | 3 | |
644 | / | |
645 | 1 --- 2 --- 4 --- 5 | |
646 | ------------ | |
647 | ||
1b1dce4b | 648 | Authors |
7fc9d69f | 649 | ------ |
59eb68aa | 650 | Written by Junio C Hamano <gitster@pobox.com> and |
1b1dce4b | 651 | Johannes E. Schindelin <johannes.schindelin@gmx.de> |
7fc9d69f JH |
652 | |
653 | Documentation | |
654 | -------------- | |
655 | Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. | |
656 | ||
657 | GIT | |
658 | --- | |
9e1f0a85 | 659 | Part of the linkgit:git[1] suite |