Fix ExecMakeTableFunctionResult to verify that all rows returned by a SRF

returning "record" actually do have the same rowtype.  This is needed because
the parser can't realistically enforce that they will all have the same typmod,
as seen in a recent example from David Wheeler.

Back-patch to 8.0, which is as far back as we have the notion of RECORD
subtypes being distinguished by typmod.  Wheeler's example depends on
8.4-and-up features, but I suspect there may be ways to provoke similar
failures before 8.4.

diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c
index fed6176cbe5ec66e5af59b4ed09b3eaa12bf68da..4b177d253297af454aa592cfaa7084be2913b537 100644 (file)
--- a/src/backend/executor/execQual.c
+++ b/src/backend/executor/execQual.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.199.2.4 2009/12/29 17:41:25 heikki Exp $
+ *   $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.199.2.5 2010/08/26 18:55:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1632,6 +1632,16 @@ ExecMakeTableFunctionResult(ExprState *funcexpr,
 
                td = DatumGetHeapTupleHeader(result);
 
+               /*
+                * Verify all returned rows have same subtype; necessary in
+                * case the type is RECORD.
+                */
+               if (HeapTupleHeaderGetTypeId(td) != tupdesc->tdtypeid ||
+                   HeapTupleHeaderGetTypMod(td) != tupdesc->tdtypmod)
+                   ereport(ERROR,
+                           (errcode(ERRCODE_DATATYPE_MISMATCH),
+                            errmsg("rows returned by function are not all of the same row type")));
+
                /*
                 * tuplestore_puttuple needs a HeapTuple not a bare
                 * HeapTupleHeader, but it doesn't need all the fields.