# git-rerere

## NAME



           git-rerere - Reuse recorded resolution of conflicted merges
    


## SYNOPSIS



           _git rerere_ [clear | forget <pathspec>... | diff | status | remaining | gc]
    


## DESCRIPTION



           In a workflow employing relatively long lived topic branches, the
           developer sometimes needs to resolve the same conflicts over and
           over again until the topic branches are done (either merged to the
           "release" branch, or sent out and accepted upstream).
    
           This command assists the developer in this process by recording
           conflicted automerge results and corresponding hand resolve
           results on the initial manual merge, and applying previously
           recorded hand resolutions to their corresponding automerge
           results.
    
               **Note**
    
               You need to set the configuration variable **rerere.enabled** in
               order to enable this command.
    


## COMMANDS



           Normally, _git rerere_ is run without arguments or
           user-intervention. However, it has several commands that allow it
           to interact with its working state.
    
           _clear_
               Reset the metadata used by rerere if a merge resolution is to
               be aborted. Calling _git am [--skip|--abort]_ or _git rebase_
               _[--skip|--abort]_ will automatically invoke this command.
    
           _forget_ <pathspec>
               Reset the conflict resolutions which rerere has recorded for
               the current conflict in <pathspec>.
    
           _diff_
               Display diffs for the current state of the resolution. It is
               useful for tracking what has changed while the user is
               resolving conflicts. Additional arguments are passed directly
               to the system _diff_ command installed in PATH.
    
           _status_
               Print paths with conflicts whose merge resolution rerere will
               record.
    
           _remaining_
               Print paths with conflicts that have not been autoresolved by
               rerere. This includes paths whose resolutions cannot be
               tracked by rerere, such as conflicting submodules.
    
           _gc_
               Prune records of conflicted merges that occurred a long time
               ago. By default, unresolved conflicts older than 15 days and
               resolved conflicts older than 60 days are pruned. These
               defaults are controlled via the **gc.rerereUnresolved** and
               **gc.rerereResolved** configuration variables respectively.
    


## DISCUSSION



           When your topic branch modifies an overlapping area that your
           master branch (or upstream) touched since your topic branch forked
           from it, you may want to test it with the latest master, even
           before your topic branch is ready to be pushed upstream:
    
                             o---*---o topic
                            /
                   o---o---o---*---o---o master
    
           For such a test, you need to merge master and topic somehow. One
           way to do it is to pull master into the topic branch:
    
                       $ git switch topic
                       $ git merge master
    
                             o---*---o---+ topic
                            /           /
                   o---o---o---*---o---o master
    
           The commits marked with ***** touch the same area in the same file;
           you need to resolve the conflicts when creating the commit marked
           with **+**. Then you can test the result to make sure your
           work-in-progress still works with what is in the latest master.
    
           After this test merge, there are two ways to continue your work on
           the topic. The easiest is to build on top of the test merge commit
           **+** , and when your work in the topic branch is finally ready, pull
           the topic branch into master, and/or ask the upstream to pull from
           you. By that time, however, the master or the upstream might have
           been advanced since the test merge **+** , in which case the final
           commit graph would look like this:
    
                       $ git switch topic
                       $ git merge master
                       $ ... work on both topic and master branches
                       $ git switch master
                       $ git merge topic
    
                             o---*---o---+---o---o topic
                            /           /         \
                   o---o---o---*---o---o---o---o---+ master
    
           When your topic branch is long-lived, however, your topic branch
           would end up having many such "Merge from master" commits on it,
           which would unnecessarily clutter the development history. Readers
           of the Linux kernel mailing list may remember that Linus
           complained about such too frequent test merges when a subsystem
           maintainer asked to pull from a branch full of "useless merges".
    
           As an alternative, to keep the topic branch clean of test merges,
           you could blow away the test merge, and keep building on top of
           the tip before the test merge:
    
                       $ git switch topic
                       $ git merge master
                       $ git reset --hard HEAD^ ;# rewind the test merge
                       $ ... work on both topic and master branches
                       $ git switch master
                       $ git merge topic
    
                             o---*---o-------o---o topic
                            /                     \
                   o---o---o---*---o---o---o---o---+ master
    
           This would leave only one merge commit when your topic branch is
           finally ready and merged into the master branch. This merge would
           require you to resolve the conflict, introduced by the commits
           marked with *****. However, this conflict is often the same conflict
           you resolved when you created the test merge you blew away. _git_
           _rerere_ helps you resolve this final conflicted merge using the
           information from your earlier hand resolve.
    
           Running the _git rerere_ command immediately after a conflicted
           automerge records the conflicted working tree files, with the
           usual conflict markers <<<<<<<, **=======** , and >>>>>>> in them.
           Later, after you are done resolving the conflicts, running _git_
           _rerere_ again will record the resolved state of these files.
           Suppose you did this when you created the test merge of master
           into the topic branch.
    
           Next time, after seeing the same conflicted automerge, running _git_
           _rerere_ will perform a three-way merge between the earlier
           conflicted automerge, the earlier manual resolution, and the
           current conflicted automerge. If this three-way merge resolves
           cleanly, the result is written out to your working tree file, so
           you do not have to manually resolve it. Note that _git rerere_
           leaves the index file alone, so you still need to do the final
           sanity checks with **git diff**(or **git diff -c**) and _git add_ when you
           are satisfied.
    
           As a convenience measure, _git merge_ automatically invokes _git_
           _rerere_ upon exiting with a failed automerge and _git rerere_ records
           the hand resolve when it is a new conflict, or reuses the earlier
           hand resolve when it is not. _git commit_ also invokes _git rerere_
           when committing a merge result. What this means is that you do not
           have to do anything special yourself (besides enabling the
           rerere.enabled config variable).
    
           In our example, when you do the test merge, the manual resolution
           is recorded, and it will be reused when you do the actual merge
           later with the updated master and topic branch, as long as the
           recorded resolution is still applicable.
    
           The information _git rerere_ records is also used when running _git_
           _rebase_. After blowing away the test merge and continuing
           development on the topic branch:
    
                             o---*---o-------o---o topic
                            /
                   o---o---o---*---o---o---o---o   master
    
                       $ git rebase master topic
    
                                                 o---*---o-------o---o topic
                                                /
                   o---o---o---*---o---o---o---o   master
    
           you could run **git rebase master topic** , to bring yourself up to
           date before your topic is ready to be sent upstream. This would
           result in falling back to a three-way merge, and it would conflict
           the same way as the test merge you resolved earlier. _git rerere_
           will be run by _git rebase_ to help you resolve this conflict.
    
           [NOTE] _git rerere_ relies on the conflict markers in the file to
           detect the conflict. If the file already contains lines that look
           the same as lines with conflict markers, _git rerere_ may fail to
           record a conflict resolution. To work around this, the
           **conflict-marker-size** setting in gitattributes(5) can be used.
    


## GIT



           Part of the git(1) suite
    


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