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At times, it can be useful to selectively merge some of the changes
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in a branch, but not all of them. This is commonly referred to as
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*cherrypicking*. Here are some examples of where cherrypicking is
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* selectively taking fixes from the main development branch into
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* selectively taking improvements out of an experimental branch into
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To merge only the changes made by revision X in branch ``foo``,
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To merge only the changes up to revision X in branch ``foo``,
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To merge only the changes since revision X in branch ``foo``,
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To merge only the changes from revision X to revision Y in branch ``foo``,
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Like a normal merge, you must explicitly commit a cherrypick. You may wish
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to see the changes made using ``bzr diff``, and run your test suite if any,
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Unlike a normal merge, Bazaar does not currently track cherrypicks.
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In particular, the changes look like a normal commit and the (internal)
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revision history of the changes from the other branch is lost.
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In many cases where they are useful (see above), this is not a major
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problem because there are good reasons why a full merge should never
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be done at a later time. In other cases, additional conflicts will need
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to be resolved when the changes are merged again.
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Cherrypicking can be used to reverse a set of changes made by giving an
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upper bound in the revision range which is *below* the lower bound.
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For example, to back-out changes made in revision 10, the command is::
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If you want to take most changes, but not all, from somewhere else, you
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may wish to do a normal merge followed by a few reverse cherrypicks.
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Merging uncommitted changes
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---------------------------
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If you have several branches and you accidently start making changes in the
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wrong one, here are the steps to take to correct this. Assuming you began
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working in branch ``foo`` when you meant to work in branch ``bar``:
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1. Change into branch ``bar``.
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2. Run ``bzr merge --uncommitted foo``
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3. Check the changes came across (``bzr diff``)
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4. Change into branch ``foo``
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5. Run ``bzr revert``.
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.. TODO Selective file merging?
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Another option to normal merging is *rebasing*, i.e. making it look like
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the current branch originated from a different point than it did.
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Rebasing is supported in Bazaar by the ``rebase`` command provided by
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the ``rebase`` plugin.
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The ``rebase`` command takes the location of another branch on which
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the branch in the current working directory will be rebased. If a branch
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is not specified then the parent branch is used, and this is usually the
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The first step identifies the revisions that are in the current branch
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that are not in the parent branch. The current branch is then set to be
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at the same revision as the target branch, and each revision is replayed
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on top of the branch. At the end of the process it will appear as though
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your current branch was branched off the current last revision of the target.
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Each revision that is replayed may cause conflicts in the tree. If this
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happens the command will stop and allow you to fix them up. Resolve the
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commits as you would for a ``merge``, and then run ``bzr resolve`` to
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marked them as resolved. Once you have resolved all the conflicts, you
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should run ``bzr rebase-continue`` to continue the rebase operation.
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If conflicts are encountered and you decide not to continue,
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you can run ``bzr rebase-abort``. You can also use ``rebase-todo`` to
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show the list of commits still to be replayed.
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Note: Some users coming from central VCS tools with poor merge tracking
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like rebasing because it's similar to how they are use to working in older
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tools, or because "perfectly clean" history seems important. Before rebasing
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in Bazaar, think about whether a normal merge is a better choice. In
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particular, rebasing a private branch before sharing it is OK but
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rebasing after sharing a branch with someone else is **strongly** discouraged.
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doc/en/user-guide/adv_merging.txt
