| git-rebase(1) |
| ============= |
| |
| NAME |
| ---- |
| git-rebase - Reapply commits on top of another base tip |
| |
| SYNOPSIS |
| -------- |
| [verse] |
| 'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] |
| [--onto <newbase> | --keep-base] [<upstream> [<branch>]] |
| 'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>] |
| --root [<branch>] |
| 'git rebase' (--continue | --skip | --abort | --quit | --edit-todo | --show-current-patch) |
| |
| DESCRIPTION |
| ----------- |
| If `<branch>` is specified, `git rebase` will perform an automatic |
| `git switch <branch>` before doing anything else. Otherwise |
| it remains on the current branch. |
| |
| If `<upstream>` is not specified, the upstream configured in |
| `branch.<name>.remote` and `branch.<name>.merge` options will be used (see |
| linkgit:git-config[1] for details) and the `--fork-point` option is |
| assumed. If you are currently not on any branch or if the current |
| branch does not have a configured upstream, the rebase will abort. |
| |
| All changes made by commits in the current branch but that are not |
| in `<upstream>` are saved to a temporary area. This is the same set |
| of commits that would be shown by `git log <upstream>..HEAD`; or by |
| `git log 'fork_point'..HEAD`, if `--fork-point` is active (see the |
| description on `--fork-point` below); or by `git log HEAD`, if the |
| `--root` option is specified. |
| |
| The current branch is reset to `<upstream>` or `<newbase>` if the |
| `--onto` option was supplied. This has the exact same effect as |
| `git reset --hard <upstream>` (or `<newbase>`). `ORIG_HEAD` is set |
| to point at the tip of the branch before the reset. |
| |
| [NOTE] |
| `ORIG_HEAD` is not guaranteed to still point to the previous branch tip |
| at the end of the rebase if other commands that write that pseudo-ref |
| (e.g. `git reset`) are used during the rebase. The previous branch tip, |
| however, is accessible using the reflog of the current branch |
| (i.e. `@{1}`, see linkgit:gitrevisions[7]). |
| |
| The commits that were previously saved into the temporary area are |
| then reapplied to the current branch, one by one, in order. Note that |
| any commits in `HEAD` which introduce the same textual changes as a commit |
| in `HEAD..<upstream>` are omitted (i.e., a patch already accepted upstream |
| with a different commit message or timestamp will be skipped). |
| |
| It is possible that a merge failure will prevent this process from being |
| completely automatic. You will have to resolve any such merge failure |
| and run `git rebase --continue`. Another option is to bypass the commit |
| that caused the merge failure with `git rebase --skip`. To check out the |
| original `<branch>` and remove the `.git/rebase-apply` working files, use |
| the command `git rebase --abort` instead. |
| |
| Assume the following history exists and the current branch is "topic": |
| |
| ------------ |
| A---B---C topic |
| / |
| D---E---F---G master |
| ------------ |
| |
| From this point, the result of either of the following commands: |
| |
| |
| git rebase master |
| git rebase master topic |
| |
| would be: |
| |
| ------------ |
| A'--B'--C' topic |
| / |
| D---E---F---G master |
| ------------ |
| |
| *NOTE:* The latter form is just a short-hand of `git checkout topic` |
| followed by `git rebase master`. When rebase exits `topic` will |
| remain the checked-out branch. |
| |
| If the upstream branch already contains a change you have made (e.g., |
| because you mailed a patch which was applied upstream), then that commit |
| will be skipped and warnings will be issued (if the 'merge' backend is |
| used). For example, running `git rebase master` on the following |
| history (in which `A'` and `A` introduce the same set of changes, but |
| have different committer information): |
| |
| ------------ |
| A---B---C topic |
| / |
| D---E---A'---F master |
| ------------ |
| |
| will result in: |
| |
| ------------ |
| B'---C' topic |
| / |
| D---E---A'---F master |
| ------------ |
| |
| Here is how you would transplant a topic branch based on one |
| branch to another, to pretend that you forked the topic branch |
| from the latter branch, using `rebase --onto`. |
| |
| First let's assume your 'topic' is based on branch 'next'. |
| For example, a feature developed in 'topic' depends on some |
| functionality which is found in 'next'. |
| |
| ------------ |
| o---o---o---o---o master |
| \ |
| o---o---o---o---o next |
| \ |
| o---o---o topic |
| ------------ |
| |
| We want to make 'topic' forked from branch 'master'; for example, |
| because the functionality on which 'topic' depends was merged into the |
| more stable 'master' branch. We want our tree to look like this: |
| |
| ------------ |
| o---o---o---o---o master |
| | \ |
| | o'--o'--o' topic |
| \ |
| o---o---o---o---o next |
| ------------ |
| |
| We can get this using the following command: |
| |
| git rebase --onto master next topic |
| |
| |
| Another example of --onto option is to rebase part of a |
| branch. If we have the following situation: |
| |
| ------------ |
| H---I---J topicB |
| / |
| E---F---G topicA |
| / |
| A---B---C---D master |
| ------------ |
| |
| then the command |
| |
| git rebase --onto master topicA topicB |
| |
| would result in: |
| |
| ------------ |
| H'--I'--J' topicB |
| / |
| | E---F---G topicA |
| |/ |
| A---B---C---D master |
| ------------ |
| |
| This is useful when topicB does not depend on topicA. |
| |
| A range of commits could also be removed with rebase. If we have |
| the following situation: |
| |
| ------------ |
| E---F---G---H---I---J topicA |
| ------------ |
| |
| then the command |
| |
| git rebase --onto topicA~5 topicA~3 topicA |
| |
| would result in the removal of commits F and G: |
| |
| ------------ |
| E---H'---I'---J' topicA |
| ------------ |
| |
| This is useful if F and G were flawed in some way, or should not be |
| part of topicA. Note that the argument to `--onto` and the `<upstream>` |
| parameter can be any valid commit-ish. |
| |
| In case of conflict, `git rebase` will stop at the first problematic commit |
| and leave conflict markers in the tree. You can use `git diff` to locate |
| the markers (<<<<<<) and make edits to resolve the conflict. For each |
| file you edit, you need to tell Git that the conflict has been resolved, |
| typically this would be done with |
| |
| |
| git add <filename> |
| |
| |
| After resolving the conflict manually and updating the index with the |
| desired resolution, you can continue the rebasing process with |
| |
| |
| git rebase --continue |
| |
| |
| Alternatively, you can undo the 'git rebase' with |
| |
| |
| git rebase --abort |
| |
| MODE OPTIONS |
| ------------ |
| |
| The options in this section cannot be used with any other option, |
| including not with each other: |
| |
| --continue:: |
| Restart the rebasing process after having resolved a merge conflict. |
| |
| --skip:: |
| Restart the rebasing process by skipping the current patch. |
| |
| --abort:: |
| Abort the rebase operation and reset HEAD to the original |
| branch. If `<branch>` was provided when the rebase operation was |
| started, then `HEAD` will be reset to `<branch>`. Otherwise `HEAD` |
| will be reset to where it was when the rebase operation was |
| started. |
| |
| --quit:: |
| Abort the rebase operation but `HEAD` is not reset back to the |
| original branch. The index and working tree are also left |
| unchanged as a result. If a temporary stash entry was created |
| using `--autostash`, it will be saved to the stash list. |
| |
| --edit-todo:: |
| Edit the todo list during an interactive rebase. |
| |
| --show-current-patch:: |
| Show the current patch in an interactive rebase or when rebase |
| is stopped because of conflicts. This is the equivalent of |
| `git show REBASE_HEAD`. |
| |
| OPTIONS |
| ------- |
| --onto <newbase>:: |
| Starting point at which to create the new commits. If the |
| `--onto` option is not specified, the starting point is |
| `<upstream>`. May be any valid commit, and not just an |
| existing branch name. |
| + |
| As a special case, you may use "A\...B" as a shortcut for the |
| merge base of A and B if there is exactly one merge base. You can |
| leave out at most one of A and B, in which case it defaults to HEAD. |
| |
| --keep-base:: |
| Set the starting point at which to create the new commits to the |
| merge base of `<upstream>` and `<branch>`. Running |
| `git rebase --keep-base <upstream> <branch>` is equivalent to |
| running |
| `git rebase --reapply-cherry-picks --no-fork-point --onto <upstream>...<branch> <upstream> <branch>`. |
| + |
| This option is useful in the case where one is developing a feature on |
| top of an upstream branch. While the feature is being worked on, the |
| upstream branch may advance and it may not be the best idea to keep |
| rebasing on top of the upstream but to keep the base commit as-is. As |
| the base commit is unchanged this option implies `--reapply-cherry-picks` |
| to avoid losing commits. |
| + |
| Although both this option and `--fork-point` find the merge base between |
| `<upstream>` and `<branch>`, this option uses the merge base as the _starting |
| point_ on which new commits will be created, whereas `--fork-point` uses |
| the merge base to determine the _set of commits_ which will be rebased. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| <upstream>:: |
| Upstream branch to compare against. May be any valid commit, |
| not just an existing branch name. Defaults to the configured |
| upstream for the current branch. |
| |
| <branch>:: |
| Working branch; defaults to `HEAD`. |
| |
| --apply:: |
| Use applying strategies to rebase (calling `git-am` |
| internally). This option may become a no-op in the future |
| once the merge backend handles everything the apply one does. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --empty=(drop|keep|ask):: |
| How to handle commits that are not empty to start and are not |
| clean cherry-picks of any upstream commit, but which become |
| empty after rebasing (because they contain a subset of already |
| upstream changes). With drop (the default), commits that |
| become empty are dropped. With keep, such commits are kept. |
| With ask (implied by `--interactive`), the rebase will halt when |
| an empty commit is applied allowing you to choose whether to |
| drop it, edit files more, or just commit the empty changes. |
| Other options, like `--exec`, will use the default of drop unless |
| `-i`/`--interactive` is explicitly specified. |
| + |
| Note that commits which start empty are kept (unless `--no-keep-empty` |
| is specified), and commits which are clean cherry-picks (as determined |
| by `git log --cherry-mark ...`) are detected and dropped as a |
| preliminary step (unless `--reapply-cherry-picks` or `--keep-base` is |
| passed). |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --no-keep-empty:: |
| --keep-empty:: |
| Do not keep commits that start empty before the rebase |
| (i.e. that do not change anything from its parent) in the |
| result. The default is to keep commits which start empty, |
| since creating such commits requires passing the `--allow-empty` |
| override flag to `git commit`, signifying that a user is very |
| intentionally creating such a commit and thus wants to keep |
| it. |
| + |
| Usage of this flag will probably be rare, since you can get rid of |
| commits that start empty by just firing up an interactive rebase and |
| removing the lines corresponding to the commits you don't want. This |
| flag exists as a convenient shortcut, such as for cases where external |
| tools generate many empty commits and you want them all removed. |
| + |
| For commits which do not start empty but become empty after rebasing, |
| see the `--empty` flag. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --reapply-cherry-picks:: |
| --no-reapply-cherry-picks:: |
| Reapply all clean cherry-picks of any upstream commit instead |
| of preemptively dropping them. (If these commits then become |
| empty after rebasing, because they contain a subset of already |
| upstream changes, the behavior towards them is controlled by |
| the `--empty` flag.) |
| + |
| In the absence of `--keep-base` (or if `--no-reapply-cherry-picks` is |
| given), these commits will be automatically dropped. Because this |
| necessitates reading all upstream commits, this can be expensive in |
| repositories with a large number of upstream commits that need to be |
| read. When using the 'merge' backend, warnings will be issued for each |
| dropped commit (unless `--quiet` is given). Advice will also be issued |
| unless `advice.skippedCherryPicks` is set to false (see |
| linkgit:git-config[1]). |
| + |
| `--reapply-cherry-picks` allows rebase to forgo reading all upstream |
| commits, potentially improving performance. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --allow-empty-message:: |
| No-op. Rebasing commits with an empty message used to fail |
| and this option would override that behavior, allowing commits |
| with empty messages to be rebased. Now commits with an empty |
| message do not cause rebasing to halt. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| -m:: |
| --merge:: |
| Using merging strategies to rebase (default). |
| + |
| Note that a rebase merge works by replaying each commit from the working |
| branch on top of the `<upstream>` branch. Because of this, when a merge |
| conflict happens, the side reported as 'ours' is the so-far rebased |
| series, starting with `<upstream>`, and 'theirs' is the working branch. |
| In other words, the sides are swapped. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| -s <strategy>:: |
| --strategy=<strategy>:: |
| Use the given merge strategy, instead of the default `ort`. |
| This implies `--merge`. |
| + |
| Because `git rebase` replays each commit from the working branch |
| on top of the `<upstream>` branch using the given strategy, using |
| the `ours` strategy simply empties all patches from the `<branch>`, |
| which makes little sense. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| -X <strategy-option>:: |
| --strategy-option=<strategy-option>:: |
| Pass the <strategy-option> through to the merge strategy. |
| This implies `--merge` and, if no strategy has been |
| specified, `-s ort`. Note the reversal of 'ours' and |
| 'theirs' as noted above for the `-m` option. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| include::rerere-options.txt[] |
| |
| -S[<keyid>]:: |
| --gpg-sign[=<keyid>]:: |
| --no-gpg-sign:: |
| GPG-sign commits. The `keyid` argument is optional and |
| defaults to the committer identity; if specified, it must be |
| stuck to the option without a space. `--no-gpg-sign` is useful to |
| countermand both `commit.gpgSign` configuration variable, and |
| earlier `--gpg-sign`. |
| |
| -q:: |
| --quiet:: |
| Be quiet. Implies `--no-stat`. |
| |
| -v:: |
| --verbose:: |
| Be verbose. Implies `--stat`. |
| |
| --stat:: |
| Show a diffstat of what changed upstream since the last rebase. The |
| diffstat is also controlled by the configuration option rebase.stat. |
| |
| -n:: |
| --no-stat:: |
| Do not show a diffstat as part of the rebase process. |
| |
| --no-verify:: |
| This option bypasses the pre-rebase hook. See also linkgit:githooks[5]. |
| |
| --verify:: |
| Allows the pre-rebase hook to run, which is the default. This option can |
| be used to override `--no-verify`. See also linkgit:githooks[5]. |
| |
| -C<n>:: |
| Ensure at least `<n>` lines of surrounding context match before |
| and after each change. When fewer lines of surrounding |
| context exist they all must match. By default no context is |
| ever ignored. Implies `--apply`. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --no-ff:: |
| --force-rebase:: |
| -f:: |
| Individually replay all rebased commits instead of fast-forwarding |
| over the unchanged ones. This ensures that the entire history of |
| the rebased branch is composed of new commits. |
| + |
| You may find this helpful after reverting a topic branch merge, as this option |
| recreates the topic branch with fresh commits so it can be remerged |
| successfully without needing to "revert the reversion" (see the |
| link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for |
| details). |
| |
| --fork-point:: |
| --no-fork-point:: |
| Use reflog to find a better common ancestor between `<upstream>` |
| and `<branch>` when calculating which commits have been |
| introduced by `<branch>`. |
| + |
| When `--fork-point` is active, 'fork_point' will be used instead of |
| `<upstream>` to calculate the set of commits to rebase, where |
| 'fork_point' is the result of `git merge-base --fork-point <upstream> |
| <branch>` command (see linkgit:git-merge-base[1]). If 'fork_point' |
| ends up being empty, the `<upstream>` will be used as a fallback. |
| + |
| If `<upstream>` or `--keep-base` is given on the command line, then |
| the default is `--no-fork-point`, otherwise the default is |
| `--fork-point`. See also `rebase.forkpoint` in linkgit:git-config[1]. |
| + |
| If your branch was based on `<upstream>` but `<upstream>` was rewound and |
| your branch contains commits which were dropped, this option can be used |
| with `--keep-base` in order to drop those commits from your branch. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --ignore-whitespace:: |
| Ignore whitespace differences when trying to reconcile |
| differences. Currently, each backend implements an approximation of |
| this behavior: |
| + |
| apply backend;; |
| When applying a patch, ignore changes in whitespace in context |
| lines. Unfortunately, this means that if the "old" lines being |
| replaced by the patch differ only in whitespace from the existing |
| file, you will get a merge conflict instead of a successful patch |
| application. |
| + |
| merge backend;; |
| Treat lines with only whitespace changes as unchanged when merging. |
| Unfortunately, this means that any patch hunks that were intended |
| to modify whitespace and nothing else will be dropped, even if the |
| other side had no changes that conflicted. |
| |
| --whitespace=<option>:: |
| This flag is passed to the `git apply` program |
| (see linkgit:git-apply[1]) that applies the patch. |
| Implies `--apply`. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --committer-date-is-author-date:: |
| Instead of using the current time as the committer date, use |
| the author date of the commit being rebased as the committer |
| date. This option implies `--force-rebase`. |
| |
| --ignore-date:: |
| --reset-author-date:: |
| Instead of using the author date of the original commit, use |
| the current time as the author date of the rebased commit. This |
| option implies `--force-rebase`. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --signoff:: |
| Add a `Signed-off-by` trailer to all the rebased commits. Note |
| that if `--interactive` is given then only commits marked to be |
| picked, edited or reworded will have the trailer added. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| -i:: |
| --interactive:: |
| Make a list of the commits which are about to be rebased. Let the |
| user edit that list before rebasing. This mode can also be used to |
| split commits (see SPLITTING COMMITS below). |
| + |
| The commit list format can be changed by setting the configuration option |
| rebase.instructionFormat. A customized instruction format will automatically |
| have the commit hash prepended to the format. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| -r:: |
| --rebase-merges[=(rebase-cousins|no-rebase-cousins)]:: |
| --no-rebase-merges:: |
| By default, a rebase will simply drop merge commits from the todo |
| list, and put the rebased commits into a single, linear branch. |
| With `--rebase-merges`, the rebase will instead try to preserve |
| the branching structure within the commits that are to be rebased, |
| by recreating the merge commits. Any resolved merge conflicts or |
| manual amendments in these merge commits will have to be |
| resolved/re-applied manually. `--no-rebase-merges` can be used to |
| countermand both the `rebase.rebaseMerges` config option and a previous |
| `--rebase-merges`. |
| + |
| When rebasing merges, there are two modes: `rebase-cousins` and |
| `no-rebase-cousins`. If the mode is not specified, it defaults to |
| `no-rebase-cousins`. In `no-rebase-cousins` mode, commits which do not have |
| `<upstream>` as direct ancestor will keep their original branch point, i.e. |
| commits that would be excluded by linkgit:git-log[1]'s `--ancestry-path` |
| option will keep their original ancestry by default. In `rebase-cousins` mode, |
| such commits are instead rebased onto `<upstream>` (or `<onto>`, if |
| specified). |
| + |
| It is currently only possible to recreate the merge commits using the |
| `ort` merge strategy; different merge strategies can be used only via |
| explicit `exec git merge -s <strategy> [...]` commands. |
| + |
| See also REBASING MERGES and INCOMPATIBLE OPTIONS below. |
| |
| -x <cmd>:: |
| --exec <cmd>:: |
| Append "exec <cmd>" after each line creating a commit in the |
| final history. `<cmd>` will be interpreted as one or more shell |
| commands. Any command that fails will interrupt the rebase, |
| with exit code 1. |
| + |
| You may execute several commands by either using one instance of `--exec` |
| with several commands: |
| + |
| git rebase -i --exec "cmd1 && cmd2 && ..." |
| + |
| or by giving more than one `--exec`: |
| + |
| git rebase -i --exec "cmd1" --exec "cmd2" --exec ... |
| + |
| If `--autosquash` is used, `exec` lines will not be appended for |
| the intermediate commits, and will only appear at the end of each |
| squash/fixup series. |
| + |
| This uses the `--interactive` machinery internally, but it can be run |
| without an explicit `--interactive`. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --root:: |
| Rebase all commits reachable from `<branch>`, instead of |
| limiting them with an `<upstream>`. This allows you to rebase |
| the root commit(s) on a branch. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --autosquash:: |
| --no-autosquash:: |
| When the commit log message begins with "squash! ..." or "fixup! ..." |
| or "amend! ...", and there is already a commit in the todo list that |
| matches the same `...`, automatically modify the todo list of |
| `rebase -i`, so that the commit marked for squashing comes right after |
| the commit to be modified, and change the action of the moved commit |
| from `pick` to `squash` or `fixup` or `fixup -C` respectively. A commit |
| matches the `...` if the commit subject matches, or if the `...` refers |
| to the commit's hash. As a fall-back, partial matches of the commit |
| subject work, too. The recommended way to create fixup/amend/squash |
| commits is by using the `--fixup`, `--fixup=amend:` or `--fixup=reword:` |
| and `--squash` options respectively of linkgit:git-commit[1]. |
| + |
| If the `--autosquash` option is enabled by default using the |
| configuration variable `rebase.autoSquash`, this option can be |
| used to override and disable this setting. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| --autostash:: |
| --no-autostash:: |
| Automatically create a temporary stash entry before the operation |
| begins, and apply it after the operation ends. This means |
| that you can run rebase on a dirty worktree. However, use |
| with care: the final stash application after a successful |
| rebase might result in non-trivial conflicts. |
| |
| --reschedule-failed-exec:: |
| --no-reschedule-failed-exec:: |
| Automatically reschedule `exec` commands that failed. This only makes |
| sense in interactive mode (or when an `--exec` option was provided). |
| + |
| This option applies once a rebase is started. It is preserved for the whole |
| rebase based on, in order, the command line option provided to the initial `git |
| rebase`, the `rebase.rescheduleFailedExec` configuration (see |
| linkgit:git-config[1] or "CONFIGURATION" below), or it defaults to false. |
| + |
| Recording this option for the whole rebase is a convenience feature. Otherwise |
| an explicit `--no-reschedule-failed-exec` at the start would be overridden by |
| the presence of a `rebase.rescheduleFailedExec=true` configuration when `git |
| rebase --continue` is invoked. Currently, you cannot pass |
| `--[no-]reschedule-failed-exec` to `git rebase --continue`. |
| |
| --update-refs:: |
| --no-update-refs:: |
| Automatically force-update any branches that point to commits that |
| are being rebased. Any branches that are checked out in a worktree |
| are not updated in this way. |
| + |
| If the configuration variable `rebase.updateRefs` is set, then this option |
| can be used to override and disable this setting. |
| + |
| See also INCOMPATIBLE OPTIONS below. |
| |
| INCOMPATIBLE OPTIONS |
| -------------------- |
| |
| The following options: |
| |
| * --apply |
| * --whitespace |
| * -C |
| |
| are incompatible with the following options: |
| |
| * --merge |
| * --strategy |
| * --strategy-option |
| * --autosquash |
| * --rebase-merges |
| * --interactive |
| * --exec |
| * --no-keep-empty |
| * --empty= |
| * --[no-]reapply-cherry-picks when used without --keep-base |
| * --update-refs |
| * --root when used without --onto |
| |
| In addition, the following pairs of options are incompatible: |
| |
| * --keep-base and --onto |
| * --keep-base and --root |
| * --fork-point and --root |
| |
| BEHAVIORAL DIFFERENCES |
| ----------------------- |
| |
| `git rebase` has two primary backends: 'apply' and 'merge'. (The 'apply' |
| backend used to be known as the 'am' backend, but the name led to |
| confusion as it looks like a verb instead of a noun. Also, the 'merge' |
| backend used to be known as the interactive backend, but it is now |
| used for non-interactive cases as well. Both were renamed based on |
| lower-level functionality that underpinned each.) There are some |
| subtle differences in how these two backends behave: |
| |
| Empty commits |
| ~~~~~~~~~~~~~ |
| |
| The 'apply' backend unfortunately drops intentionally empty commits, i.e. |
| commits that started empty, though these are rare in practice. It |
| also drops commits that become empty and has no option for controlling |
| this behavior. |
| |
| The 'merge' backend keeps intentionally empty commits by default (though |
| with `-i` they are marked as empty in the todo list editor, or they can |
| be dropped automatically with `--no-keep-empty`). |
| |
| Similar to the apply backend, by default the merge backend drops |
| commits that become empty unless `-i`/`--interactive` is specified (in |
| which case it stops and asks the user what to do). The merge backend |
| also has an `--empty=(drop|keep|ask)` option for changing the behavior |
| of handling commits that become empty. |
| |
| Directory rename detection |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| Due to the lack of accurate tree information (arising from |
| constructing fake ancestors with the limited information available in |
| patches), directory rename detection is disabled in the 'apply' backend. |
| Disabled directory rename detection means that if one side of history |
| renames a directory and the other adds new files to the old directory, |
| then the new files will be left behind in the old directory without |
| any warning at the time of rebasing that you may want to move these |
| files into the new directory. |
| |
| Directory rename detection works with the 'merge' backend to provide you |
| warnings in such cases. |
| |
| Context |
| ~~~~~~~ |
| |
| The 'apply' backend works by creating a sequence of patches (by calling |
| `format-patch` internally), and then applying the patches in sequence |
| (calling `am` internally). Patches are composed of multiple hunks, |
| each with line numbers, a context region, and the actual changes. The |
| line numbers have to be taken with some fuzz, since the other side |
| will likely have inserted or deleted lines earlier in the file. The |
| context region is meant to help find how to adjust the line numbers in |
| order to apply the changes to the right lines. However, if multiple |
| areas of the code have the same surrounding lines of context, the |
| wrong one can be picked. There are real-world cases where this has |
| caused commits to be reapplied incorrectly with no conflicts reported. |
| Setting `diff.context` to a larger value may prevent such types of |
| problems, but increases the chance of spurious conflicts (since it |
| will require more lines of matching context to apply). |
| |
| The 'merge' backend works with a full copy of each relevant file, |
| insulating it from these types of problems. |
| |
| Labelling of conflicts markers |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| When there are content conflicts, the merge machinery tries to |
| annotate each side's conflict markers with the commits where the |
| content came from. Since the 'apply' backend drops the original |
| information about the rebased commits and their parents (and instead |
| generates new fake commits based off limited information in the |
| generated patches), those commits cannot be identified; instead it has |
| to fall back to a commit summary. Also, when `merge.conflictStyle` is |
| set to `diff3` or `zdiff3`, the 'apply' backend will use "constructed merge |
| base" to label the content from the merge base, and thus provide no |
| information about the merge base commit whatsoever. |
| |
| The 'merge' backend works with the full commits on both sides of history |
| and thus has no such limitations. |
| |
| Hooks |
| ~~~~~ |
| |
| The 'apply' backend has not traditionally called the post-commit hook, |
| while the 'merge' backend has. Both have called the post-checkout hook, |
| though the 'merge' backend has squelched its output. Further, both |
| backends only call the post-checkout hook with the starting point |
| commit of the rebase, not the intermediate commits nor the final |
| commit. In each case, the calling of these hooks was by accident of |
| implementation rather than by design (both backends were originally |
| implemented as shell scripts and happened to invoke other commands |
| like `git checkout` or `git commit` that would call the hooks). Both |
| backends should have the same behavior, though it is not entirely |
| clear which, if any, is correct. We will likely make rebase stop |
| calling either of these hooks in the future. |
| |
| Interruptability |
| ~~~~~~~~~~~~~~~~ |
| |
| The 'apply' backend has safety problems with an ill-timed interrupt; if |
| the user presses Ctrl-C at the wrong time to try to abort the rebase, |
| the rebase can enter a state where it cannot be aborted with a |
| subsequent `git rebase --abort`. The 'merge' backend does not appear to |
| suffer from the same shortcoming. (See |
| https://lore.kernel.org/git/20200207132152.GC2868@szeder.dev/ for |
| details.) |
| |
| Commit Rewording |
| ~~~~~~~~~~~~~~~~ |
| |
| When a conflict occurs while rebasing, rebase stops and asks the user |
| to resolve. Since the user may need to make notable changes while |
| resolving conflicts, after conflicts are resolved and the user has run |
| `git rebase --continue`, the rebase should open an editor and ask the |
| user to update the commit message. The 'merge' backend does this, while |
| the 'apply' backend blindly applies the original commit message. |
| |
| Miscellaneous differences |
| ~~~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| There are a few more behavioral differences that most folks would |
| probably consider inconsequential but which are mentioned for |
| completeness: |
| |
| * Reflog: The two backends will use different wording when describing |
| the changes made in the reflog, though both will make use of the |
| word "rebase". |
| |
| * Progress, informational, and error messages: The two backends |
| provide slightly different progress and informational messages. |
| Also, the apply backend writes error messages (such as "Your files |
| would be overwritten...") to stdout, while the merge backend writes |
| them to stderr. |
| |
| * State directories: The two backends keep their state in different |
| directories under `.git/` |
| |
| include::merge-strategies.txt[] |
| |
| NOTES |
| ----- |
| |
| You should understand the implications of using `git rebase` on a |
| repository that you share. See also RECOVERING FROM UPSTREAM REBASE |
| below. |
| |
| When the rebase is run, it will first execute a `pre-rebase` hook if one |
| exists. You can use this hook to do sanity checks and reject the rebase |
| if it isn't appropriate. Please see the template `pre-rebase` hook script |
| for an example. |
| |
| Upon completion, `<branch>` will be the current branch. |
| |
| INTERACTIVE MODE |
| ---------------- |
| |
| Rebasing interactively means that you have a chance to edit the commits |
| which are rebased. You can reorder the commits, and you can |
| remove them (weeding out bad or otherwise unwanted patches). |
| |
| The interactive mode is meant for this type of workflow: |
| |
| 1. have a wonderful idea |
| 2. hack on the code |
| 3. prepare a series for submission |
| 4. submit |
| |
| where point 2. consists of several instances of |
| |
| a) regular use |
| |
| 1. finish something worthy of a commit |
| 2. commit |
| |
| b) independent fixup |
| |
| 1. realize that something does not work |
| 2. fix that |
| 3. commit it |
| |
| Sometimes the thing fixed in b.2. cannot be amended to the not-quite |
| perfect commit it fixes, because that commit is buried deeply in a |
| patch series. That is exactly what interactive rebase is for: use it |
| after plenty of "a"s and "b"s, by rearranging and editing |
| commits, and squashing multiple commits into one. |
| |
| Start it with the last commit you want to retain as-is: |
| |
| git rebase -i <after-this-commit> |
| |
| An editor will be fired up with all the commits in your current branch |
| (ignoring merge commits), which come after the given commit. You can |
| reorder the commits in this list to your heart's content, and you can |
| remove them. The list looks more or less like this: |
| |
| ------------------------------------------- |
| pick deadbee The oneline of this commit |
| pick fa1afe1 The oneline of the next commit |
| ... |
| ------------------------------------------- |
| |
| The oneline descriptions are purely for your pleasure; 'git rebase' will |
| not look at them but at the commit names ("deadbee" and "fa1afe1" in this |
| example), so do not delete or edit the names. |
| |
| By replacing the command "pick" with the command "edit", you can tell |
| `git rebase` to stop after applying that commit, so that you can edit |
| the files and/or the commit message, amend the commit, and continue |
| rebasing. |
| |
| To interrupt the rebase (just like an "edit" command would do, but without |
| cherry-picking any commit first), use the "break" command. |
| |
| If you just want to edit the commit message for a commit, replace the |
| command "pick" with the command "reword". |
| |
| To drop a commit, replace the command "pick" with "drop", or just |
| delete the matching line. |
| |
| If you want to fold two or more commits into one, replace the command |
| "pick" for the second and subsequent commits with "squash" or "fixup". |
| If the commits had different authors, the folded commit will be |
| attributed to the author of the first commit. The suggested commit |
| message for the folded commit is the concatenation of the first |
| commit's message with those identified by "squash" commands, omitting the |
| messages of commits identified by "fixup" commands, unless "fixup -c" |
| is used. In that case the suggested commit message is only the message |
| of the "fixup -c" commit, and an editor is opened allowing you to edit |
| the message. The contents (patch) of the "fixup -c" commit are still |
| incorporated into the folded commit. If there is more than one "fixup -c" |
| commit, the message from the final one is used. You can also use |
| "fixup -C" to get the same behavior as "fixup -c" except without opening |
| an editor. |
| |
| `git rebase` will stop when "pick" has been replaced with "edit" or |
| when a command fails due to merge errors. When you are done editing |
| and/or resolving conflicts you can continue with `git rebase --continue`. |
| |
| For example, if you want to reorder the last 5 commits, such that what |
| was `HEAD~4` becomes the new `HEAD`. To achieve that, you would call |
| `git rebase` like this: |
| |
| ---------------------- |
| $ git rebase -i HEAD~5 |
| ---------------------- |
| |
| And move the first patch to the end of the list. |
| |
| You might want to recreate merge commits, e.g. if you have a history |
| like this: |
| |
| ------------------ |
| X |
| \ |
| A---M---B |
| / |
| ---o---O---P---Q |
| ------------------ |
| |
| Suppose you want to rebase the side branch starting at "A" to "Q". Make |
| sure that the current `HEAD` is "B", and call |
| |
| ----------------------------- |
| $ git rebase -i -r --onto Q O |
| ----------------------------- |
| |
| Reordering and editing commits usually creates untested intermediate |
| steps. You may want to check that your history editing did not break |
| anything by running a test, or at least recompiling at intermediate |
| points in history by using the "exec" command (shortcut "x"). You may |
| do so by creating a todo list like this one: |
| |
| ------------------------------------------- |
| pick deadbee Implement feature XXX |
| fixup f1a5c00 Fix to feature XXX |
| exec make |
| pick c0ffeee The oneline of the next commit |
| edit deadbab The oneline of the commit after |
| exec cd subdir; make test |
| ... |
| ------------------------------------------- |
| |
| The interactive rebase will stop when a command fails (i.e. exits with |
| non-0 status) to give you an opportunity to fix the problem. You can |
| continue with `git rebase --continue`. |
| |
| The "exec" command launches the command in a shell (the one specified |
| in `$SHELL`, or the default shell if `$SHELL` is not set), so you can |
| use shell features (like "cd", ">", ";" ...). The command is run from |
| the root of the working tree. |
| |
| ---------------------------------- |
| $ git rebase -i --exec "make test" |
| ---------------------------------- |
| |
| This command lets you check that intermediate commits are compilable. |
| The todo list becomes like that: |
| |
| -------------------- |
| pick 5928aea one |
| exec make test |
| pick 04d0fda two |
| exec make test |
| pick ba46169 three |
| exec make test |
| pick f4593f9 four |
| exec make test |
| -------------------- |
| |
| SPLITTING COMMITS |
| ----------------- |
| |
| In interactive mode, you can mark commits with the action "edit". However, |
| this does not necessarily mean that `git rebase` expects the result of this |
| edit to be exactly one commit. Indeed, you can undo the commit, or you can |
| add other commits. This can be used to split a commit into two: |
| |
| - Start an interactive rebase with `git rebase -i <commit>^`, where |
| `<commit>` is the commit you want to split. In fact, any commit range |
| will do, as long as it contains that commit. |
| |
| - Mark the commit you want to split with the action "edit". |
| |
| - When it comes to editing that commit, execute `git reset HEAD^`. The |
| effect is that the `HEAD` is rewound by one, and the index follows suit. |
| However, the working tree stays the same. |
| |
| - Now add the changes to the index that you want to have in the first |
| commit. You can use `git add` (possibly interactively) or |
| `git gui` (or both) to do that. |
| |
| - Commit the now-current index with whatever commit message is appropriate |
| now. |
| |
| - Repeat the last two steps until your working tree is clean. |
| |
| - Continue the rebase with `git rebase --continue`. |
| |
| If you are not absolutely sure that the intermediate revisions are |
| consistent (they compile, pass the testsuite, etc.) you should use |
| `git stash` to stash away the not-yet-committed changes |
| after each commit, test, and amend the commit if fixes are necessary. |
| |
| |
| RECOVERING FROM UPSTREAM REBASE |
| ------------------------------- |
| |
| Rebasing (or any other form of rewriting) a branch that others have |
| based work on is a bad idea: anyone downstream of it is forced to |
| manually fix their history. This section explains how to do the fix |
| from the downstream's point of view. The real fix, however, would be |
| to avoid rebasing the upstream in the first place. |
| |
| To illustrate, suppose you are in a situation where someone develops a |
| 'subsystem' branch, and you are working on a 'topic' that is dependent |
| on this 'subsystem'. You might end up with a history like the |
| following: |
| |
| ------------ |
| o---o---o---o---o---o---o---o master |
| \ |
| o---o---o---o---o subsystem |
| \ |
| *---*---* topic |
| ------------ |
| |
| If 'subsystem' is rebased against 'master', the following happens: |
| |
| ------------ |
| o---o---o---o---o---o---o---o master |
| \ \ |
| o---o---o---o---o o'--o'--o'--o'--o' subsystem |
| \ |
| *---*---* topic |
| ------------ |
| |
| If you now continue development as usual, and eventually merge 'topic' |
| to 'subsystem', the commits from 'subsystem' will remain duplicated forever: |
| |
| ------------ |
| o---o---o---o---o---o---o---o master |
| \ \ |
| o---o---o---o---o o'--o'--o'--o'--o'--M subsystem |
| \ / |
| *---*---*-..........-*--* topic |
| ------------ |
| |
| Such duplicates are generally frowned upon because they clutter up |
| history, making it harder to follow. To clean things up, you need to |
| transplant the commits on 'topic' to the new 'subsystem' tip, i.e., |
| rebase 'topic'. This becomes a ripple effect: anyone downstream from |
| 'topic' is forced to rebase too, and so on! |
| |
| There are two kinds of fixes, discussed in the following subsections: |
| |
| Easy case: The changes are literally the same.:: |
| |
| This happens if the 'subsystem' rebase was a simple rebase and |
| had no conflicts. |
| |
| Hard case: The changes are not the same.:: |
| |
| This happens if the 'subsystem' rebase had conflicts, or used |
| `--interactive` to omit, edit, squash, or fixup commits; or |
| if the upstream used one of `commit --amend`, `reset`, or |
| a full history rewriting command like |
| https://github.com/newren/git-filter-repo[`filter-repo`]. |
| |
| |
| The easy case |
| ~~~~~~~~~~~~~ |
| |
| Only works if the changes (patch IDs based on the diff contents) on |
| 'subsystem' are literally the same before and after the rebase |
| 'subsystem' did. |
| |
| In that case, the fix is easy because 'git rebase' knows to skip |
| changes that are already present in the new upstream (unless |
| `--reapply-cherry-picks` is given). So if you say |
| (assuming you're on 'topic') |
| ------------ |
| $ git rebase subsystem |
| ------------ |
| you will end up with the fixed history |
| ------------ |
| o---o---o---o---o---o---o---o master |
| \ |
| o'--o'--o'--o'--o' subsystem |
| \ |
| *---*---* topic |
| ------------ |
| |
| |
| The hard case |
| ~~~~~~~~~~~~~ |
| |
| Things get more complicated if the 'subsystem' changes do not exactly |
| correspond to the ones before the rebase. |
| |
| NOTE: While an "easy case recovery" sometimes appears to be successful |
| even in the hard case, it may have unintended consequences. For |
| example, a commit that was removed via `git rebase |
| --interactive` will be **resurrected**! |
| |
| The idea is to manually tell `git rebase` "where the old 'subsystem' |
| ended and your 'topic' began", that is, what the old merge base |
| between them was. You will have to find a way to name the last commit |
| of the old 'subsystem', for example: |
| |
| * With the 'subsystem' reflog: after `git fetch`, the old tip of |
| 'subsystem' is at `subsystem@{1}`. Subsequent fetches will |
| increase the number. (See linkgit:git-reflog[1].) |
| |
| * Relative to the tip of 'topic': knowing that your 'topic' has three |
| commits, the old tip of 'subsystem' must be `topic~3`. |
| |
| You can then transplant the old `subsystem..topic` to the new tip by |
| saying (for the reflog case, and assuming you are on 'topic' already): |
| ------------ |
| $ git rebase --onto subsystem subsystem@{1} |
| ------------ |
| |
| The ripple effect of a "hard case" recovery is especially bad: |
| 'everyone' downstream from 'topic' will now have to perform a "hard |
| case" recovery too! |
| |
| REBASING MERGES |
| --------------- |
| |
| The interactive rebase command was originally designed to handle |
| individual patch series. As such, it makes sense to exclude merge |
| commits from the todo list, as the developer may have merged the |
| then-current `master` while working on the branch, only to rebase |
| all the commits onto `master` eventually (skipping the merge |
| commits). |
| |
| However, there are legitimate reasons why a developer may want to |
| recreate merge commits: to keep the branch structure (or "commit |
| topology") when working on multiple, inter-related branches. |
| |
| In the following example, the developer works on a topic branch that |
| refactors the way buttons are defined, and on another topic branch |
| that uses that refactoring to implement a "Report a bug" button. The |
| output of `git log --graph --format=%s -5` may look like this: |
| |
| ------------ |
| * Merge branch 'report-a-bug' |
| |\ |
| | * Add the feedback button |
| * | Merge branch 'refactor-button' |
| |\ \ |
| | |/ |
| | * Use the Button class for all buttons |
| | * Extract a generic Button class from the DownloadButton one |
| ------------ |
| |
| The developer might want to rebase those commits to a newer `master` |
| while keeping the branch topology, for example when the first topic |
| branch is expected to be integrated into `master` much earlier than the |
| second one, say, to resolve merge conflicts with changes to the |
| DownloadButton class that made it into `master`. |
| |
| This rebase can be performed using the `--rebase-merges` option. |
| It will generate a todo list looking like this: |
| |
| ------------ |
| label onto |
| |
| # Branch: refactor-button |
| reset onto |
| pick 123456 Extract a generic Button class from the DownloadButton one |
| pick 654321 Use the Button class for all buttons |
| label refactor-button |
| |
| # Branch: report-a-bug |
| reset refactor-button # Use the Button class for all buttons |
| pick abcdef Add the feedback button |
| label report-a-bug |
| |
| reset onto |
| merge -C a1b2c3 refactor-button # Merge 'refactor-button' |
| merge -C 6f5e4d report-a-bug # Merge 'report-a-bug' |
| ------------ |
| |
| In contrast to a regular interactive rebase, there are `label`, `reset` |
| and `merge` commands in addition to `pick` ones. |
| |
| The `label` command associates a label with the current HEAD when that |
| command is executed. These labels are created as worktree-local refs |
| (`refs/rewritten/<label>`) that will be deleted when the rebase |
| finishes. That way, rebase operations in multiple worktrees linked to |
| the same repository do not interfere with one another. If the `label` |
| command fails, it is rescheduled immediately, with a helpful message how |
| to proceed. |
| |
| The `reset` command resets the HEAD, index and worktree to the specified |
| revision. It is similar to an `exec git reset --hard <label>`, but |
| refuses to overwrite untracked files. If the `reset` command fails, it is |
| rescheduled immediately, with a helpful message how to edit the todo list |
| (this typically happens when a `reset` command was inserted into the todo |
| list manually and contains a typo). |
| |
| The `merge` command will merge the specified revision(s) into whatever |
| is HEAD at that time. With `-C <original-commit>`, the commit message of |
| the specified merge commit will be used. When the `-C` is changed to |
| a lower-case `-c`, the message will be opened in an editor after a |
| successful merge so that the user can edit the message. |
| |
| If a `merge` command fails for any reason other than merge conflicts (i.e. |
| when the merge operation did not even start), it is rescheduled immediately. |
| |
| By default, the `merge` command will use the `ort` merge strategy for |
| regular merges, and `octopus` for octopus merges. One can specify a |
| default strategy for all merges using the `--strategy` argument when |
| invoking rebase, or can override specific merges in the interactive |
| list of commands by using an `exec` command to call `git merge` |
| explicitly with a `--strategy` argument. Note that when calling `git |
| merge` explicitly like this, you can make use of the fact that the |
| labels are worktree-local refs (the ref `refs/rewritten/onto` would |
| correspond to the label `onto`, for example) in order to refer to the |
| branches you want to merge. |
| |
| Note: the first command (`label onto`) labels the revision onto which |
| the commits are rebased; The name `onto` is just a convention, as a nod |
| to the `--onto` option. |
| |
| It is also possible to introduce completely new merge commits from scratch |
| by adding a command of the form `merge <merge-head>`. This form will |
| generate a tentative commit message and always open an editor to let the |
| user edit it. This can be useful e.g. when a topic branch turns out to |
| address more than a single concern and wants to be split into two or |
| even more topic branches. Consider this todo list: |
| |
| ------------ |
| pick 192837 Switch from GNU Makefiles to CMake |
| pick 5a6c7e Document the switch to CMake |
| pick 918273 Fix detection of OpenSSL in CMake |
| pick afbecd http: add support for TLS v1.3 |
| pick fdbaec Fix detection of cURL in CMake on Windows |
| ------------ |
| |
| The one commit in this list that is not related to CMake may very well |
| have been motivated by working on fixing all those bugs introduced by |
| switching to CMake, but it addresses a different concern. To split this |
| branch into two topic branches, the todo list could be edited like this: |
| |
| ------------ |
| label onto |
| |
| pick afbecd http: add support for TLS v1.3 |
| label tlsv1.3 |
| |
| reset onto |
| pick 192837 Switch from GNU Makefiles to CMake |
| pick 918273 Fix detection of OpenSSL in CMake |
| pick fdbaec Fix detection of cURL in CMake on Windows |
| pick 5a6c7e Document the switch to CMake |
| label cmake |
| |
| reset onto |
| merge tlsv1.3 |
| merge cmake |
| ------------ |
| |
| CONFIGURATION |
| ------------- |
| |
| include::includes/cmd-config-section-all.txt[] |
| |
| include::config/rebase.txt[] |
| include::config/sequencer.txt[] |
| |
| GIT |
| --- |
| Part of the linkgit:git[1] suite |