Rev 2: It *is* simpler. Basically, merge_sort ensures that the last mainline revision *is* the one that merged it. in http://bzr.arbash-meinel.com/plugins/find_mainline_rev

[John Arbash Meinel]

At http://bzr.arbash-meinel.com/plugins/find_mainline_rev

------------------------------------------------------------
revno: 2
revision-id:john at arbash-meinel.com-20071101193731-9k12asz8pye6b21l
parent: john at arbash-meinel.com-20071101191856-nq75rlbq0nwzm1tr
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: find_mainline_rev
timestamp: Thu 2007-11-01 14:37:31 -0500
message:
  It *is* simpler. Basically, merge_sort ensures that the last mainline revision *is* the one that merged it.
modified:
  __init__.py                    __init__.py-20071101191826-bpibqad1s9oeqw1d-1
-------------- next part --------------
=== modified file '__init__.py'
--- a/__init__.py	2007-11-01 19:18:56 +0000
+++ b/__init__.py	2007-11-01 19:37:31 +0000
@@ -35,63 +35,13 @@
         [(node, parents) for node, parents in rev_graph.iteritems()],
         tip_revision_id, generate_revno=True)
 
-    node_offset = {}
-    nodes = []
-    target_node_offset = None
-
-    # We've checked these nodes already
-    # not_in_ancestry_of = set()
-
-    def _check_in_ancestry(mainline_rev_id):
-        found = False
-        nodes_to_check = [mainline_rev_id]
-        checked_nodes = set()
-
-        while nodes_to_check:
-            node = nodes_to_check.pop()
-            checked_nodes.add(node)
-            for parent in rev_graph[node]:
-                # if parent in not_in_ancestry_of:
-                #     # We've checked this one in the past
-                #     continue
-                if (parent not in node_offset
-                    or node_offset[parent] > target_node_offset):
-                    # This parent is too old
-                    continue
-                if parent == revision_id:
-                    # Found it
-                    return True
-                nodes_to_check.append(parent)
-        # if we have gotten this far, then the node is not in the ancestry of
-        # any of the nodes we checked
-        # not_in_ancestry_of.update(checked_nodes)
-        return False
-
-    # topo_sorted starts from the tip and works backwards
-    # this will be the list of all mainline revisions that happen after the
-    # merged revision.
-    mainline_revs = []
+    last_mainline = None
     for num, rev_id, depth, dotted_revno, eo_merge in topo_sorted:
-        node_offset[rev_id] = num
+        if depth == 0:
+            last_mainline = (dotted_revno, rev_id)
         if rev_id == revision_id:
-            target_node_offset = num
-            print 'found node at %d' % (num,)
-            if depth == 0:
-                return revision_id
-            break
-        elif depth == 0:
-            mainline_revs.append(rev_id)
-
-    for main_rev_id in reversed(mainline_revs):
-        # We have a mainline node, check if the desired node is in the
-        # ancestry.
-        if _check_in_ancestry(main_rev_id):
-            return main_rev_id
-        assert 'it should have been the last one'
-    trace.warning("somehow we didn't find it in the ancestry,"
-                  " even though get_revision_graph said it was.")
-    import pdb; pdb.set_trace()
-    return None
+            return last_mainline
+    assert False, 'we should never get here'
 
 
 class cmd_find_mainline_rev(commands.Command):
@@ -106,14 +56,16 @@
         a_branch.lock_read()
         try:
             revision_id = revision[0].in_history(a_branch).rev_id
-            mainline_revision_id = _find_mainline_rev(a_branch, revision_id)
+            mainline_info = _find_mainline_rev(a_branch, revision_id)
         finally:
             a_branch.unlock()
-        if mainline_revision_id is None:
+        if mainline_info is None:
             trace.note('Revision not present in ancestry')
             return 1
         else:
-            self.outf.write(mainline_revision_id + '\n')
+            split_revno, mainline_revision_id = mainline_info
+            assert len(split_revno) == 1
+            self.outf.write('%d %s\n' % (split_revno[0], mainline_revision_id))
 
 
 commands.register_command(cmd_find_mainline_rev)