Changeset 3266

Timestamp:

05/29/07 19:52:59 (1 year ago)

Author:

mscott

Message:

Merge in 'cascade-temp', a short-lived branch to fix circular
reference cascade delete problems.

Files:

• trunk/Schevo/schevo/transaction.py (modified) (5 diffs)
• trunk/Schevo/tests/test_on_delete.py (modified) (1 diff)

trunk/Schevo/schevo/transaction.py

@@ -376 +376 @@
-
-
+def find_chains(entity):
+    db = entity.sys.db
+    traversed = set()
+    chains = []
+    _find_chains(db, entity, traversed, chains)
+    return chains
+
+
+def _find_chains(db, entity, traversed, chains, chain=None):
+    if chain is None:
+        chain = []
+    chain.append(entity)
+    if entity in traversed:
+        chains.append(chain)
+        return
+    traversed.add(entity)
+    entity_extent_name = entity._extent.name
+    for (e_name, f_name), others in entity.sys.links().iteritems():
+        extent = db.extent(e_name)
+        for referrer in others:
+            _find_chains(db, referrer, traversed, chains, chain)
+
+
-class Delete(Transaction):
-    """Delete an existing entity instance."""
@@ -414 +437 @@
-                'Original entity revision was %i, is now %i'
-                % (self._rev, entity._rev))
+        deletes = self._deletes
-        # Before execute callback.
-        self._before_execute(db, entity)
@@ -427 +451 @@
-        # also requesting cascade deletion.
-        restricter_keys = set(restricters) - set(cascaders)
+        # Starting at the entity whose deletion is requested, find
+        # chains of circular references that contain that entity, and
+        # make sure they are not in the restricters.
+        chains = find_chains(entity)
+        for chain in chains:
+            if chain[0] == entity and chain[0] == chain[-1]:
+                chain = frozenset(chain)
+                for referrer, restricter_set in restricters.iteritems():
+                    for f_name, referred in frozenset(restricter_set):
+                        if referred in chain:
+                            restricter_set.remove((f_name, referred))
+                    if len(restricter_set) == 0:
+                        restricter_keys.discard(referrer)
-        if len(restricter_keys) != 0:
-            # Raise DeleteRestricted if there are any restricters left
@@ -486 +523 @@
-            referrers.add((extent_name, oid, referrer))
-        # Delete entities in a deterministic (sorted) fashion.
+        deletes.add((entity.__class__, entity._oid))
-        for extent_name, oid, referrer in sorted(referrers):
-
+
+
-                # Skip the original entity whose deletion was
-                # requested, since we must delete it using a call to
-
+
+
-                continue
-            if not db._extent_contains_oid(extent_name, oid):
@@ -497 +537 @@
-                continue
-            tx = referrer.t.delete()
+            tx._deletes.update(deletes)
-            db.execute(tx, strict=False)
-        # Attempt to delete the entity itself.

trunk/Schevo/tests/test_on_delete.py

@@ -131 +131 @@
-
-        bam = f.entity('Bam')
+
+
+    # ----------------------------------------------------------------
-
-