Rev 3547: Handle when there are more than 2 LCAs while searching for the unique lca. in http://bzr.arbash-meinel.com/branches/bzr/1.7-dev/merge_lca_multi

[John Arbash Meinel]

At http://bzr.arbash-meinel.com/branches/bzr/1.7-dev/merge_lca_multi

------------------------------------------------------------
revno: 3547
revision-id: john at arbash-meinel.com-20080730021916-65dpdenvz27emgnk
parent: john at arbash-meinel.com-20080729230216-xt8zje18edlwsnb7
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: merge_lca_multi
timestamp: Tue 2008-07-29 21:19:16 -0500
message:
  Handle when there are more than 2 LCAs while searching for the unique lca.
-------------- next part --------------
=== modified file 'bzrlib/merge.py'
--- a/bzrlib/merge.py	2008-07-29 23:02:16 +0000
+++ b/bzrlib/merge.py	2008-07-30 02:19:16 +0000
@@ -363,8 +363,16 @@
             elif len(lcas) == 1:
                 self.base_rev_id = list(lcas)[0]
             else: # len(lcas) > 1
-                self.base_rev_id = self.revision_graph.find_unique_lca(
-                                        *lcas)
+                if len(lcas) > 2:
+                    # find_unique_lca can only handle 2 nodes, so we have to
+                    # start back at the beginning. It is a shame to traverse
+                    # the graph again, but better than re-implementing
+                    # find_unique_lca.
+                    self.base_rev_id = self.revision_graph.find_unique_lca(
+                                            revisions[0], revisions[1])
+                else:
+                    self.base_rev_id = self.revision_graph.find_unique_lca(
+                                            *lcas)
                 self._is_criss_cross = True
             if self.base_rev_id == NULL_REVISION:
                 raise UnrelatedBranches()

=== modified file 'bzrlib/tests/test_merge.py'
--- a/bzrlib/tests/test_merge.py	2008-07-29 23:02:16 +0000
+++ b/bzrlib/tests/test_merge.py	2008-07-30 02:19:16 +0000
@@ -1176,6 +1176,24 @@
         self.assertEqual(['C-id', 'B-id'], [t.get_revision_id()
                                             for t in merger._lca_trees])
 
+    def test_find_base_triple_criss_cross(self):
+        #       A-.
+        #      / \ \
+        #     B   C F # F is merged into both branches
+        #     |\ /| |
+        #     | X | |\
+        #     |/ \| | :
+        #   : D   E |  
+        #    \|   |/ 
+        #     G   H
+        builder = self.setup_criss_cross_graph()
+        builder.build_snapshot('F-id', ['A-id'], [])
+        builder.build_snapshot('H-id', ['E-id', 'F-id'], [])
+        builder.build_snapshot('G-id', ['D-id', 'F-id'], [])
+        merger = self.make_Merger(builder, 'H-id')
+        self.assertEqual(['B-id', 'C-id', 'F-id'],
+                         [t.get_revision_id() for t in merger._lca_trees])
+
     def test_no_criss_cross_passed_to_merge_type(self):
         class LCATreesMerger(LoggingMerger):
             supports_lca_trees = True