Rev 5858: Update some documentation, also fix a serious bug in the old code. in http://bazaar.launchpad.net/~jameinel/bzr/2.4-set-parent-trees-delta-282941

[John Arbash Meinel]

At http://bazaar.launchpad.net/~jameinel/bzr/2.4-set-parent-trees-delta-282941

------------------------------------------------------------
revno: 5858
revision-id: john at arbash-meinel.com-20110518104503-d571kyyo148b364b
parent: john at arbash-meinel.com-20110518095244-og67674lnpf6djxo
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: 2.4-set-parent-trees-delta-282941
timestamp: Wed 2011-05-18 12:45:03 +0200
message:
  Update some documentation, also fix a serious bug in the old code.
  
  Specifically, any real_add is going to fail with _get_entry(1,) because the
  _get_entry code notices that the entry is 'a' on the basis tree. So we fall
  back to _get_entry(0). Another option comes to mind, though, which is to
  always call _get_entry(0,) without a file_id, then check the file_id, and
  only call _get_entry(1, ) if the [0] file_id doesn't match.
  That might save some bisection lookups in common cases.
-------------- next part --------------
=== modified file 'bzrlib/dirstate.py'
--- a/bzrlib/dirstate.py	2011-05-18 09:52:44 +0000
+++ b/bzrlib/dirstate.py	2011-05-18 10:45:03 +0000
@@ -1654,6 +1654,16 @@
         for old_path, new_path, file_id, new_details, real_add in adds:
             entry = self._get_entry(1, file_id, new_path)
             if entry[0] is None:
+                # This entry doesn't exist in tree 1, but it might just be an
+                # 'absent' record which we are filling in. Check in tree 0
+                # Note: we never have to check old_path, because by now
+                #       old_path is always None.
+                entry = self._get_entry(0, path_utf8=new_path)
+                if entry[0] is not None and entry[0][2] != file_id:
+                    # Something does exist at that path in tree0, but it is
+                    # with a different file_id
+                    entry = (None, None)
+            if entry[0] is None:
                 # entry_key (dirname, basename, file_id) doesn't exist in any
                 # tree yet, so we need to create a new record.
                 dirname, basename = osutils.split(new_path)