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 6c287f92d0a99aff694a1f6dcd9ebba00cbbd976..58bcdddb16334f0750a3e97dd998c9901c8db56e 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 1.226.2.3 2010/02/18 18:42:04 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.226.2.4 2010/08/26 18:54:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1724,6 +1724,16 @@ 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.