Rev 4518: Add comments in the finally sections as to why we want them. in http://bazaar.launchpad.net/~jameinel/bzr/1.17-lru-cleanup

[John Arbash Meinel]

At http://bazaar.launchpad.net/~jameinel/bzr/1.17-lru-cleanup

------------------------------------------------------------
revno: 4518
revision-id: john at arbash-meinel.com-20090708154351-u0t41fwjqm28pbnu
parent: john at arbash-meinel.com-20090708142804-i9rkpi9dmnu7v3x1
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: 1.17-lru-cleanup
timestamp: Wed 2009-07-08 10:43:51 -0500
message:
  Add comments in the finally sections as to why we want them.
-------------- next part --------------
=== modified file 'bzrlib/lru_cache.py'
--- a/bzrlib/lru_cache.py	2009-07-08 14:28:04 +0000
+++ b/bzrlib/lru_cache.py	2009-07-08 15:43:51 +0000
@@ -52,8 +52,9 @@
             if self.cleanup is not None:
                 self.cleanup(self.key, self.value)
         finally:
+            # cleanup might raise an exception, but we want to make sure
+            # to break refcycles, etc
             self.cleanup = None
-            # Just make sure to break any refcycles, etc
             self.value = None
 
 
@@ -161,6 +162,8 @@
             try:
                 node.run_cleanup()
             finally:
+                # Maintain the LRU properties, even if cleanup raises an
+                # exception
                 node.value = value
                 node.cleanup = cleanup
                 self._record_access(node)
@@ -249,7 +252,8 @@
         try:
             node.run_cleanup()
         finally:
-            # Now remove this node from the linked list
+            # cleanup might raise an exception, but we want to make sure to
+            # maintain the linked list
             if node.prev is not None:
                 node.prev.next_key = node.next_key
             if node.next_key is not _null_key: