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index 2074f319a02a9ef6a97ece2129170701024d33cb..895d7503100632f5ab79af548fed3b3a6d79c413 100644 (file)
[--index-filter <command>] [--parent-filter <command>]
[--msg-filter <command>] [--commit-filter <command>]
[--tag-name-filter <command>] [--subdirectory-filter <directory>]
- [-d <directory>] <new-branch-name> [<rev-list options>...]
+ [--original <namespace>] [-d <directory>] [-f | --force]
+ [<rev-list options>...]
DESCRIPTION
-----------
-Lets you rewrite git revision history by creating a new branch from
-your current branch, applying custom filters on each revision.
+Lets you rewrite git revision history by rewriting the branches mentioned
+in the <rev-list options>, applying custom filters on each revision.
Those filters can modify each tree (e.g. removing a file or running
a perl rewrite on all files) or information about each commit.
Otherwise, all information (including original commit times or merge
information) will be preserved.
-The command takes the new branch name as a mandatory argument and
-the filters as optional arguments. If you specify no filters, the
-commits will be recommitted without any changes, which would normally
-have no effect and result in the new branch pointing to the same
-branch as your current branch. Nevertheless, this may be useful in
-the future for compensating for some git bugs or such, therefore
-such a usage is permitted.
+The command will only rewrite the _positive_ refs mentioned in the
+command line (i.e. if you pass 'a..b', only 'b' will be rewritten).
+If you specify no filters, the commits will be recommitted without any
+changes, which would normally have no effect. Nevertheless, this may be
+useful in the future for compensating for some git bugs or such,
+therefore such a usage is permitted.
-WARNING! The rewritten history will have different object names for all
+*WARNING*! The rewritten history will have different object names for all
the objects and will not converge with the original branch. You will not
be able to easily push and distribute the rewritten branch on top of the
original branch. Please do not use this command if you do not know the
full implications, and avoid using it anyway, if a simple single commit
would suffice to fix your problem.
-Always verify that the rewritten version is correct before disposing
-the original branch.
+Always verify that the rewritten version is correct: The original refs,
+if different from the rewritten ones, will be stored in the namespace
+'refs/original/'.
Note that since this operation is extensively I/O expensive, it might
-be a good idea to redirect the temporary directory off-disk, e.g. on
-tmpfs. Reportedly the speedup is very noticeable.
+be a good idea to redirect the temporary directory off-disk with the
+'-d' option, e.g. on tmpfs. Reportedly the speedup is very noticeable.
Filters
~~~~~~~
The filters are applied in the order as listed below. The <command>
-argument is always evaluated in shell using the 'eval' command.
+argument is always evaluated in shell using the 'eval' command (with the
+notable exception of the commit filter, for technical reasons).
Prior to that, the $GIT_COMMIT environment variable will be set to contain
the id of the commit being rewritten. Also, GIT_AUTHOR_NAME,
GIT_AUTHOR_EMAIL, GIT_AUTHOR_DATE, GIT_COMMITTER_NAME, GIT_COMMITTER_EMAIL,
-and GIT_COMMITTER_DATE is set according to the current commit.
+and GIT_COMMITTER_DATE are set according to the current commit.
A 'map' function is available that takes an "original sha1 id" argument
and outputs a "rewritten sha1 id" if the commit has been already
-rewritten, fails otherwise; the 'map' function can return several
-ids on separate lines if your commit filter emitted multiple commits.
+rewritten, and "original sha1 id" otherwise; the 'map' function can
+return several ids on separate lines if your commit filter emitted
+multiple commits.
OPTIONS
directory set to the root of the checked out tree. The new tree
is then used as-is (new files are auto-added, disappeared files
are auto-removed - neither .gitignore files nor any other ignore
- rules HAVE ANY EFFECT!).
+ rules *HAVE ANY EFFECT*!).
--index-filter <command>::
This is the filter for rewriting the index. It is similar to the
As a special extension, the commit filter may emit multiple
commit ids; in that case, ancestors of the original commit will
have all of them as parents.
++
+You can use the 'map' convenience function in this filter, and other
+convenience functions, too. For example, calling 'skip_commit "$@"'
+will leave out the current commit (but not its changes! If you want
+that, use gitlink:git-rebase[1] instead).
--tag-name-filter <command>::
This is the filter for rewriting tag names. When passed,
tag name is expected on standard output.
+
The original tags are not deleted, but can be overwritten;
-use "--tag-name-filter=cat" to simply update the tags. In this
+use "--tag-name-filter cat" to simply update the tags. In this
case, be very careful and make sure you have the old tags
backed up in case the conversion has run afoul.
+
definition impossible to preserve signatures at any rate.)
--subdirectory-filter <directory>::
- Only ever look at the history, which touches the given subdirectory.
- The result will contain that directory as its project root.
+ Only look at the history which touches the given subdirectory.
+ The result will contain that directory (and only that) as its
+ project root.
+
+--original <namespace>::
+ Use this option to set the namespace where the original commits
+ will be stored. The default value is 'refs/original'.
-d <directory>::
Use this option to set the path to the temporary directory used for
does this in the '.git-rewrite/' directory but you can override
that choice by this parameter.
+-f|--force::
+ `git filter-branch` refuses to start with an existing temporary
+ directory or when there are already refs starting with
+ 'refs/original/', unless forced.
+
<rev-list-options>::
When options are given after the new branch name, they will
be passed to gitlink:git-rev-list[1]. Only commits in the resulting
or copyright violation) from all commits:
-------------------------------------------------------
-git filter-branch --tree-filter 'rm filename' newbranch
+git filter-branch --tree-filter 'rm filename' HEAD
-------------------------------------------------------
A significantly faster version:
--------------------------------------------------------------------------------
-git filter-branch --index-filter 'git update-index --remove filename' newbranch
--------------------------------------------------------------------------------
+--------------------------------------------------------------------------
+git filter-branch --index-filter 'git update-index --remove filename' HEAD
+--------------------------------------------------------------------------
-Now, you will get the rewritten history saved in the branch 'newbranch'
-(your current branch is left untouched).
+Now, you will get the rewritten history saved in HEAD.
-To "etch-graft" a commit to the revision history (set a commit to be
-the parent of the current initial commit and propagate that):
+To set a commit (which typically is at the tip of another
+history) to be the parent of the current initial commit, in
+order to paste the other history behind the current history:
-----------------------------------------------------------------------
-git filter-branch --parent-filter sed\ 's/^$/-p <graft-id>/' newbranch
-----------------------------------------------------------------------
+-------------------------------------------------------------------
+git filter-branch --parent-filter 'sed "s/^\$/-p <graft-id>/"' HEAD
+-------------------------------------------------------------------
-(if the parent string is empty - therefore we are dealing with the
-initial commit - add graftcommit as a parent). Note that this assumes
+(if the parent string is empty - which happens when we are dealing with
+the initial commit - add graftcommit as a parent). Note that this assumes
history with a single root (that is, no merge without common ancestors
happened). If this is not the case, use:
--------------------------------------------------------------------------------
+--------------------------------------------------------------------------
git filter-branch --parent-filter \
- 'cat; test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>"' newbranch
--------------------------------------------------------------------------------
+ 'cat; test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>"' HEAD
+--------------------------------------------------------------------------
+
+or even simpler:
+
+-----------------------------------------------
+echo "$commit-id $graft-id" >> .git/info/grafts
+git filter-branch $graft-id..HEAD
+-----------------------------------------------
To remove commits authored by "Darl McBribe" from the history:
git filter-branch --commit-filter '
if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ];
then
- shift;
- while [ -n "$1" ];
- do
- shift;
- echo "$1";
- shift;
- done;
+ skip_commit "$@";
else
git commit-tree "$@";
- fi' newbranch
+ fi' HEAD
------------------------------------------------------------------------------
+The function 'skip_commit' is defined as follows:
+
+--------------------------
+skip_commit()
+{
+ shift;
+ while [ -n "$1" ];
+ do
+ shift;
+ map "$1";
+ shift;
+ done;
+}
+--------------------------
+
The shift magic first throws away the tree id and then the -p
parameters. Note that this handles merges properly! In case Darl
committed a merge between P1 and P2, it will be propagated properly
and all children of the merge will become merge commits with P1,P2
as their parents instead of the merge commit.
+
To restrict rewriting to only part of the history, specify a revision
range in addition to the new branch name. The new branch name will
point to the top-most revision that a 'git rev-list' of this range
will print.
-Note that the changes introduced by the commits, and not reverted by
-subsequent commits, will still be in the rewritten branch. If you want
+*NOTE* the changes introduced by the commits, and which are not reverted
+by subsequent commits, will still be in the rewritten branch. If you want
to throw out _changes_ together with the commits, you should use the
interactive mode of gitlink:git-rebase[1].
+
Consider this history:
------------------
To rewrite only commits D,E,F,G,H, but leave A, B and C alone, use:
--------------------------------
-git filter-branch ... new-H C..H
+git filter-branch ... C..H
--------------------------------
To rewrite commits E,F,G,H, use one of these:
----------------------------------------
-git filter-branch ... new-H C..H --not D
-git filter-branch ... new-H D..H --not C
+git filter-branch ... C..H --not D
+git filter-branch ... D..H --not C
----------------------------------------
To move the whole tree into a subdirectory, or remove it from there:
'git ls-files -s | sed "s-\t-&newsubdir/-" |
GIT_INDEX_FILE=$GIT_INDEX_FILE.new \
git update-index --index-info &&
- mv $GIT_INDEX_FILE.new $GIT_INDEX_FILE' directorymoved
+ mv $GIT_INDEX_FILE.new $GIT_INDEX_FILE' HEAD
---------------------------------------------------------------