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Diffstat (limited to 'Documentation/git-rebase.txt')
| -rw-r--r-- | Documentation/git-rebase.txt | 271 |
1 files changed, 231 insertions, 40 deletions
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt index 59c1b021a6..823f2a4638 100644 --- a/Documentation/git-rebase.txt +++ b/Documentation/git-rebase.txt @@ -8,21 +8,23 @@ git-rebase - Forward-port local commits to the updated upstream head SYNOPSIS -------- [verse] -'git rebase' [-i | --interactive] [-v | --verbose] [-m | --merge] - [-s <strategy> | --strategy=<strategy>] - [-C<n>] [ --whitespace=<option>] [-p | --preserve-merges] - [--onto <newbase>] <upstream> [<branch>] +'git rebase' [-i | --interactive] [options] [--onto <newbase>] + <upstream> [<branch>] +'git rebase' [-i | --interactive] [options] --onto <newbase> + --root [<branch>] + 'git rebase' --continue | --skip | --abort DESCRIPTION ----------- -If <branch> is specified, 'git-rebase' will perform an automatic +If <branch> is specified, 'git rebase' will perform an automatic `git checkout <branch>` before doing anything else. Otherwise it remains on the current branch. 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`. +of commits that would be shown by `git log <upstream>..HEAD` (or +`git log HEAD`, if --root is specified). The current branch is reset to <upstream>, or <newbase> if the --onto option was supplied. This has the exact same effect as @@ -92,7 +94,7 @@ 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 feature developed in 'topic' depends on some +For example, a feature developed in 'topic' depends on some functionality which is found in 'next'. ------------ @@ -103,9 +105,9 @@ functionality which is found in 'next'. o---o---o topic ------------ -We would want to make 'topic' forked from branch 'master', -for example because the functionality 'topic' branch depend on -got merged into more stable 'master' branch, like this: +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 @@ -168,8 +170,8 @@ 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 +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 @@ -185,11 +187,18 @@ desired resolution, you can continue the rebasing process with git rebase --continue -Alternatively, you can undo the 'git-rebase' with +Alternatively, you can undo the 'git rebase' with git rebase --abort +CONFIGURATION +------------- + +rebase.stat:: + Whether to show a diffstat of what changed upstream since the last + rebase. False by default. + OPTIONS ------- <newbase>:: @@ -219,18 +228,42 @@ OPTIONS Use merging strategies to rebase. When the recursive (default) merge strategy is used, this allows rebase to be aware of renames on the upstream side. ++ +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. -s <strategy>:: --strategy=<strategy>:: - Use the given merge strategy; can be supplied more than - once to specify them in the order they should be tried. - If there is no `-s` option, a built-in list of strategies - is used instead ('git-merge-recursive' when merging a single - head, 'git-merge-octopus' otherwise). This implies --merge. + Use the given merge strategy. + If there is no `-s` option 'git merge-recursive' is used + instead. 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 discards all patches from the <branch>, +which makes little sense. + +-q:: +--quiet:: + Be quiet. Implies --no-stat. -v:: --verbose:: - Display a diffstat of what changed upstream since the last rebase. + 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]. -C<n>:: Ensure at least <n> lines of surrounding context match before @@ -238,9 +271,23 @@ OPTIONS context exist they all must match. By default no context is ever ignored. ---whitespace=<nowarn|warn|error|error-all|strip>:: - This flag is passed to the 'git-apply' program +-f:: +--force-rebase:: + Force the rebase even if the current branch is a descendant + of the commit you are rebasing onto. Normally the command will + exit with the message "Current branch is up to date" in such a + situation. + +--ignore-whitespace:: +--whitespace=<option>:: + These flag are passed to the 'git apply' program (see linkgit:git-apply[1]) that applies the patch. + Incompatible with the --interactive option. + +--committer-date-is-author-date:: +--ignore-date:: + These flags are passed to 'git am' to easily change the dates + of the rebased commits (see linkgit:git-am[1]). -i:: --interactive:: @@ -250,18 +297,35 @@ OPTIONS -p:: --preserve-merges:: - Instead of ignoring merges, try to recreate them. This option - only works in interactive mode. + Instead of ignoring merges, try to recreate them. + +--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. Must be used with --onto, and + will skip changes already contained in <newbase> (instead of + <upstream>). When used together with --preserve-merges, 'all' + root commits will be rewritten to have <newbase> as parent + instead. + +--autosquash:: + When the commit log message begins with "squash! ..." (or + "fixup! ..."), and there is a commit whose title begins with + 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`). ++ +This option is only valid when '--interactive' option is used. include::merge-strategies.txt[] NOTES ----- -When you rebase a branch, you are changing its history in a way that -will cause problems for anyone who already has a copy of the branch -in their repository and tries to pull updates from you. You should -understand the implications of using 'git-rebase' on a repository that -you share. + +You should understand the implications of using 'git rebase' on a +repository that you share. See also RECOVERING FROM UPSTREAM REBASE +below. When the git-rebase command is run, it will first execute a "pre-rebase" hook if one exists. You can use this hook to do sanity checks and @@ -315,27 +379,33 @@ pick fa1afe1 The oneline of the next commit ... ------------------------------------------- -The oneline descriptions are purely for your pleasure; 'git-rebase' will +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 +'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. +If you just want to edit the commit message for a commit, replace the +command "pick" with the command "reword". + If you want to fold two or more commits into one, replace the command -"pick" with "squash" for the second and subsequent commit. If the -commits had different authors, it will attribute the squashed commit to -the author of the first commit. +"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 commit +messages of the first commit and of those with the "squash" command, +but omits the commit messages of commits with the "fixup" command. -In both cases, or when a "pick" does not succeed (because of merge -errors), the loop will stop to let you fix things, and you can continue -the loop with `git rebase --continue`. +'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' like this: ---------------------- $ git rebase -i HEAD~5 @@ -365,7 +435,7 @@ 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 +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: @@ -381,7 +451,7 @@ add other commits. This can be used to split a commit into two: - 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. + 'git gui' (or both) to do that. - Commit the now-current index with whatever commit message is appropriate now. @@ -392,10 +462,131 @@ add other commits. This can be used to split a commit into two: 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 +'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---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 + `filter-branch`. + + +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. 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! + + Authors ------ Written by Junio C Hamano <gitster@pobox.com> and |