man pages section 1: User Commands

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Updated: July 2014

git-rerere (1)


git-rerere - Reuse recorded resolution of conflicted merges


git rerere [clear|forget <pathspec>|diff|status|gc]


Git Manual                                          GIT-RERERE(1)

     git-rerere - Reuse recorded resolution of conflicted merges

     git rerere [clear|forget <pathspec>|diff|status|gc]

     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.


         You need to set the configuration variable
         rerere.enabled in order to enable this command.

     Normally, git rerere is run without arguments or
     user-intervention. However, it has several commands that
     allow it to interact with its working state.

         This resets 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>
         This resets the conflict resolutions which rerere has
         recorded for the current conflict in <pathspec>.

         This displays 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.

         Like diff, but this only prints the filenames that will
         be tracked for resolutions.

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Git Manual                                          GIT-RERERE(1)

         This prunes 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.

     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 checkout 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 checkout topic
                 $ git merge master
                 $ ... work on both topic and master branches
                 $ git checkout master
                 $ git merge topic

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Git Manual                                          GIT-RERERE(1)

                       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 checkout topic
                 $ git merge master
                 $ git reset --hard HEAD^ ;# rewind the test merge
                 $ ... work on both topic and master branches
                 $ git checkout 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

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Git Manual                                          GIT-RERERE(1)

     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

     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

     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.

     Part of the git(1) suite

     See attributes(5) for descriptions of the following

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Git Manual                                          GIT-RERERE(1)

     |Availability   | developer/versioning/git |
     |Stability      | Uncommitted              |
     This software was built from source available at  The original
     community source was downloaded from  http://git-

     Further information about this software can be found on the
     open source community website at

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