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diff --git a/third_party/git/Documentation/git-rebase.txt b/third_party/git/Documentation/git-rebase.txt deleted file mode 100644 index 6156609cf7..0000000000 --- a/third_party/git/Documentation/git-rebase.txt +++ /dev/null @@ -1,1053 +0,0 @@ -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>] - [<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. - -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. 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 - -CONFIGURATION -------------- - -include::config/rebase.txt[] - -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. - -<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. - ---continue:: - Restart the rebasing process after having resolved a merge conflict. - ---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. - ---keep-empty:: - Keep the commits that do not change anything from its - parents in the result. -+ -See also INCOMPATIBLE OPTIONS below. - ---allow-empty-message:: - By default, rebasing commits with an empty message will fail. - This option overrides that behavior, allowing commits with empty - messages to be rebased. -+ -See also INCOMPATIBLE OPTIONS below. - ---skip:: - Restart the rebasing process by skipping the current patch. - ---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`. - --m:: ---merge:: - 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. -+ -See also INCOMPATIBLE OPTIONS below. - --s <strategy>:: ---strategy=<strategy>:: - 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 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 recursive`. Note the reversal of 'ours' and - 'theirs' as noted above for the `-m` option. -+ -See also INCOMPATIBLE OPTIONS below. - ---rerere-autoupdate:: ---no-rerere-autoupdate:: - Allow the rerere mechanism to update the index with the - result of auto-conflict resolution if possible. - --S[<keyid>]:: ---gpg-sign[=<keyid>]:: - 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. - --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. -+ -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 either <upstream> or --root is given on the command line, then the -default is `--no-fork-point`, otherwise the default is `--fork-point`. - ---ignore-whitespace:: ---whitespace=<option>:: - These flag are passed to the 'git apply' program - (see linkgit:git-apply[1]) that applies the patch. -+ -See also INCOMPATIBLE OPTIONS below. - ---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]). -+ -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 long commit hash prepended to the format. -+ -See also INCOMPATIBLE OPTIONS below. - --r:: ---rebase-merges[=(rebase-cousins|no-rebase-cousins)]:: - 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. -+ -By default, or when `no-rebase-cousins` was specified, 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. If -the `rebase-cousins` mode is turned on, such commits are instead rebased -onto `<upstream>` (or `<onto>`, if specified). -+ -The `--rebase-merges` mode is similar in spirit to the deprecated -`--preserve-merges`, but in contrast to that option works well in interactive -rebases: commits can be reordered, inserted and dropped at will. -+ -It is currently only possible to recreate the merge commits using the -`recursive` 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. - --p:: ---preserve-merges:: - [DEPRECATED: use `--rebase-merges` instead] Recreate merge commits - instead of flattening the history by replaying commits a merge commit - introduces. Merge conflict resolutions or manual amendments to merge - commits are not preserved. -+ -This uses the `--interactive` machinery internally, but combining it -with the `--interactive` option explicitly is generally not a good -idea unless you know what you are doing (see BUGS below). -+ -See also 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. When used with --onto, it - will skip changes already contained in <newbase> (instead of - <upstream>) whereas without --onto it will operate on every change. - When used together with both --onto and --preserve-merges, - 'all' root commits will be rewritten to have <newbase> as parent - instead. -+ -See also INCOMPATIBLE OPTIONS below. - ---autosquash:: ---no-autosquash:: - When the commit log message begins with "squash! ..." (or - "fixup! ..."), 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`). 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/squash commits is by using - the `--fixup`/`--squash` options 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). - -INCOMPATIBLE OPTIONS --------------------- - -The following options: - - * --committer-date-is-author-date - * --ignore-date - * --whitespace - * --ignore-whitespace - * -C - -are incompatible with the following options: - - * --merge - * --strategy - * --strategy-option - * --allow-empty-message - * --[no-]autosquash - * --rebase-merges - * --preserve-merges - * --interactive - * --exec - * --keep-empty - * --edit-todo - * --root when used in combination with --onto - -In addition, the following pairs of options are incompatible: - - * --preserve-merges and --interactive - * --preserve-merges and --signoff - * --preserve-merges and --rebase-merges - * --rebase-merges and --strategy - * --rebase-merges and --strategy-option - -BEHAVIORAL DIFFERENCES ------------------------ - -There are some subtle differences how the backends behave. - -Empty commits -~~~~~~~~~~~~~ - -The am backend drops any "empty" commits, regardless of whether the -commit started empty (had no changes relative to its parent to -start with) or ended empty (all changes were already applied -upstream in other commits). - -The interactive backend drops commits by default that -started empty and halts if it hits a commit that ended up empty. -The `--keep-empty` option exists for the interactive backend to allow -it to keep commits that started empty. - -Directory rename detection -~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Directory rename heuristics are enabled in the merge and interactive -backends. Due to the lack of accurate tree information, directory -rename detection is disabled in the am backend. - -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 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 -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 commit -messages of the first commit and of those with the "squash" command, -but omits the commit messages of commits with the "fixup" command. - -'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 - `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! - -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. - -At this time, the `merge` command will *always* use the `recursive` -merge strategy for regular merges, and `octopus` for octopus merges, -with no way to choose a different one. To work around -this, an `exec` command can be used to call `git merge` explicitly, -using the fact that the labels are worktree-local refs (the ref -`refs/rewritten/onto` would correspond to the label `onto`, for example). - -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 ------------- - -BUGS ----- -The todo list presented by the deprecated `--preserve-merges --interactive` -does not represent the topology of the revision graph (use `--rebase-merges` -instead). Editing commits and rewording their commit messages should work -fine, but attempts to reorder commits tend to produce counterintuitive results. -Use `--rebase-merges` in such scenarios instead. - -For example, an attempt to rearrange ------------- -1 --- 2 --- 3 --- 4 --- 5 ------------- -to ------------- -1 --- 2 --- 4 --- 3 --- 5 ------------- -by moving the "pick 4" line will result in the following history: ------------- - 3 - / -1 --- 2 --- 4 --- 5 ------------- - -GIT ---- -Part of the linkgit:git[1] suite |