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 865b8a6ab65b60bd0362e61dc876faa87ad7af5b..8d2d368e0b4063df3c1b3ae6a481fe4ca4f543f8 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 1.171.4.4 2007/02/06 17:35:41 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/executor/execQual.c,v 1.171.4.5 2010/08/26 18:55:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1538,6 +1538,16 @@ 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.