From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 23 May 2006 17:09:18 +0000 (+0000)
Subject: Klugy fix for bug #2447: we can't expand a whole-row reference to NEW
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=0a1da8297a9aea51446ac455e308e538167e4ce5;p=users%2Fbernd%2Fpostgres.git

Klugy fix for bug #2447: we can't expand a whole-row reference to NEW
in a rule WHERE expression while inserting it into the original query,
because the 8.0 ResolveNew API is wrongly designed.  This is fixed in 8.1
but I'm disinclined to risk back-porting the changes.  Instead, just stop
the coredump and instead issue the same 'cannot handle whole-row reference'
message that 7.4 and before generated in this situation.
---

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 53088370b4..cb75abd235 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -1046,7 +1046,7 @@ CopyAndAddInvertedQual(Query *parsetree,
 		new_qual = ResolveNew(new_qual,
 							  PRS2_NEW_VARNO,
 							  0,
-							  parsetree->rtable,
+							  NIL,				/* fix bug #2447 */
 							  parsetree->targetList,
 							  event,
 							  rt_index);
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 66dd414298..cf8e776ad6 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -942,6 +942,24 @@ ResolveNew_mutator(Node *node, ResolveNew_context *context)
 				RowExpr    *rowexpr;
 				List	   *fields;
 
+				/*
+				 * Klugy fix for bug #2447: we can't expand a whole-row
+				 * reference to "NEW" in a rule WHERE expression while
+				 * inserting it into the original query, because its varno
+				 * will be PRS2_NEW_VARNO which is not the rtindex of the RTE
+				 * we should use.  The 8.0 ResolveNew API is wrongly designed.
+				 * We aren't going to try to back-port the 8.1 API, just avoid
+				 * crashing.  (This never worked before 8.0, either.)
+				 * CopyAndAddInvertedQual passes NIL for target_rtable, so
+				 * testing for NIL would be sufficient, but let's put in a
+				 * full check on the rtindex for safety.
+				 */
+				if (this_varno < 1 ||
+					this_varno > list_length(context->target_rtable))
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("cannot handle whole-row reference")));
+
 				/*
 				 * If generating an expansion for a var of a named rowtype
 				 * (ie, this is a plain relation RTE), then we must