X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=Documentation%2Fgit-rebase.txt;h=c8ad86a56fc6bff70cb6e7c74cc8ef10ef2da73e;hb=160d2bc35382fb23beb99457e9111d15554bf223;hp=e0412e0866db8f80e8bbc8f33caaa659461d90aa;hpb=f23ffbe890d36e277f02d4a84c2b52de3a4e3173;p=git.git

diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index e0412e086..30487de48 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -8,25 +8,28 @@ 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' --continue | --skip | --abort
+'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
-`git reset --hard <upstream>` (or <newbase>).
+`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
@@ -38,8 +41,8 @@ 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 restore the
-original <branch> and remove the .dotest working files, use the command
-`git rebase --abort` instead.
+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":
 
@@ -52,8 +55,8 @@ Assume the following history exists and the current branch is "topic":
 From this point, the result of either of the following commands:
 
 
-    git-rebase master
-    git-rebase master topic
+    git rebase master
+    git rebase master topic
 
 would be:
 
@@ -68,7 +71,7 @@ followed by `git rebase master`.
 
 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
+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):
 
@@ -91,7 +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'.
 
 ------------
@@ -102,9 +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
@@ -116,7 +119,7 @@ got merged into more stable 'master' branch, like this:
 
 We can get this using the following command:
 
-    git-rebase --onto master next topic
+    git rebase --onto master next topic
 
 
 Another example of --onto option is to rebase part of a
@@ -132,7 +135,7 @@ branch.  If we have the following situation:
 
 then the command
 
-    git-rebase --onto master topicA topicB
+    git rebase --onto master topicA topicB
 
 would result in:
 
@@ -155,7 +158,7 @@ the following situation:
 
 then the command
 
-    git-rebase --onto topicA~5 topicA~3 topicA
+    git rebase --onto topicA~5 topicA~3 topicA
 
 would result in the removal of commits F and G:
 
@@ -167,8 +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
@@ -184,7 +187,7 @@ 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
@@ -213,21 +216,27 @@ OPTIONS
 --skip::
 	Restart the rebasing process by skipping the current patch.
 
--m, \--merge::
+-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.
 
--s <strategy>, \--strategy=<strategy>::
+-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.
+	is used instead ('git-merge-recursive' when merging a single
+	head, 'git-merge-octopus' otherwise).  This implies --merge.
 
--v, \--verbose::
+-v::
+--verbose::
 	Display a diffstat of what changed upstream since the last rebase.
 
+--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
 	and after each change.  When fewer lines of surrounding
@@ -235,29 +244,39 @@ OPTIONS
 	ever ignored.
 
 --whitespace=<nowarn|warn|error|error-all|strip>::
-	This flag is passed to the `git-apply` program
+	This flag is passed to the 'git-apply' program
 	(see linkgit:git-apply[1]) that applies the patch.
+	Incompatible with the --interactive option.
 
--i, \--interactive::
+-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).
 
--p, \--preserve-merges::
-	Instead of ignoring merges, try to recreate them.  This option
-	only works in interactive mode.
+-p::
+--preserve-merges::
+	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.
 
 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.
 
-When the git rebase command is run, it will first execute a "pre-rebase"
+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.
@@ -309,12 +328,12 @@ 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.
 
@@ -329,7 +348,7 @@ the loop 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
@@ -359,40 +378,161 @@ 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:
 
-- Start an interactive rebase with 'git rebase -i <commit>^', where
+- 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
+- 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 linkgit:git-add[1] (possibly interactively) and/or
-  linkgit:git-gui[1] to do that.
+  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'.
+- 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
-linkgit:git-stash[1] 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, or squash 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 <junkio@cox.net> and
+Written by Junio C Hamano <gitster@pobox.com> and
 Johannes E. Schindelin <johannes.schindelin@gmx.de>
 
 Documentation
@@ -401,4 +541,4 @@ Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
 
 GIT
 ---
-Part of the linkgit:git[7] suite
+Part of the linkgit:git[1] suite