Rework fix for #bea/8fc# : be crashes on outdated id-cache

Now we re-run CachedPathID.init in an 'append' mode, rather than
starting over from scratch.  This avoids problems like

  ======================================================================
  ERROR: Should not be able to add children to non-directories.
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File ".../be.wtk/libbe/storage/base.py", line 680, in test_add_invalid_directory
      self.s.add('child', 'parent', directory=False)
    File ".../be.wtk/libbe/storage/base.py", line 248, in add
      self._add(id, *args, **kwargs)
    File ".../be.wtk/libbe/storage/vcs/base.py", line 737, in _add
      path = self._cached_path_id.add_id(id, parent)
    File ".../be.wtk/libbe/storage/vcs/base.py", line 267, in add_id
      parent_path = self.path(parent, relpath=True)
    File ".../be.wtk/libbe/storage/vcs/base.py", line 246, in path
      raise InvalidID(uuid)
  InvalidID: parent in revision None

and similar.

1 files changed, 10 insertions, 7 deletions

diff --git a/libbe/storage/vcs/base.py b/libbe/storage/vcs/base.py
index 2269424..8335cfa 100644
--- a/libbe/storage/vcs/base.py
+++ b/libbe/storage/vcs/base.py
@@ -182,13 +182,16 @@ class CachedPathID (object):
         self._cache_path = os.path.join(
             self._root, self._spacer_dirs[0], 'id-cache')
 
-    def init(self, verbose=True):
+    def init(self, verbose=True, cache=None):
         """
         Create cache file for an existing .be directory.
         File if multiple lines of the form:
           UUID\tPATH
         """
-        self._cache = {}
+        if cache == None:
+            self._cache = {}
+        else:
+            self._cache = cache
         spaced_root = os.path.join(self._root, self._spacer_dirs[0])
         for dirpath, dirnames, filenames in os.walk(spaced_root):
             if dirpath == spaced_root:
@@ -202,8 +205,10 @@ class CachedPathID (object):
                     self._cache[id] = relpath
             except InvalidPath:
                 pass
-        self._changed = True
-        self.disconnect()
+        if self._cache != cache:
+            self._changed = True
+        if cache == None:
+            self.disconnect()
 
     def destroy(self):
         if os.path.exists(self._cache_path):
@@ -239,9 +244,7 @@ class CachedPathID (object):
         else:
             extra = fields[1:]
         if uuid not in self._cache:
-            self.disconnect()
-            self.init(verbose=False)
-            self.connect()
+            self.init(verbose=False, cache=self._cache)
             if uuid not in self._cache:
                 raise InvalidID(uuid)
         if relpath == True: