Fix AfterTriggerSaveEvent to use a test and elog, not just Assert, to check

that it's called within an AfterTriggerBeginQuery/AfterTriggerEndQuery pair.
The RI cascade triggers suppress that overhead on the assumption that they
are always run non-deferred, so it's possible to violate the condition if
someone mistakenly changes pg_trigger to mark such a trigger deferred.
We don't really care about supporting that, but throwing an error instead
of crashing seems desirable.  Per report from Marcelo Costa.

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 1660ef0f04e5d9aaad866a0b2f9715a93fc011ff..5c97e5feabe8df4b3881e215846dbab9f3355a0e 100644 (file)
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.195.2.6 2008/10/25 03:32:58 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.195.2.7 2009/10/27 20:14:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3157,8 +3157,15 @@ AfterTriggerSaveEvent(ResultRelInfo *relinfo, int event, bool row_trigger,
        ItemPointerData oldctid;
        ItemPointerData newctid;
 
+       /*
+        * Check state.  We use normal tests not Asserts because it is possible
+        * to reach here in the wrong state given misconfigured RI triggers,
+        * in particular deferring a cascade action trigger.
+        */
        if (afterTriggers == NULL)
                elog(ERROR, "AfterTriggerSaveEvent() called outside of transaction");
+       if (afterTriggers->query_depth < 0)
+               elog(ERROR, "AfterTriggerSaveEvent() called outside of query");
 
        /*
         * Get the CTID's of OLD and NEW