[ODBC-134] Fix and testcase. Fetch would fail, if unbound column

contained NULL, and for that column some arbitrary descriptor field was
set by application(but not value/len/ind buffer ptrs). The bug affected
ADO, as that is something it can do in some cases with CursorLocation adUseClient

ma_desc.c

@@ -973,7 +973,9 @@ SQLRETURN MADB_DescSetField(SQLHDESC DescriptorHandle,
       break;
     }
 
-    if (DescRecord)
+    /* inUse is only used to check if column/parameter was bound or not. Thus we do not set it for each field, but only for those,
+       that make column/parameter "bound" */
+    if (DescRecord && (DescRecord->DataPtr != NULL || DescRecord->OctetLengthPtr != NULL || DescRecord->IndicatorPtr != NULL))
       DescRecord->inUse= 1;
   }
   return ret;

test/result2.c

@@ -1140,6 +1140,22 @@ ODBC_TEST(t_odbc73)
   return OK;
 }
 
+
+ODBC_TEST(t_odbc134)
+{
+  SQLHANDLE Ard;
+
+  OK_SIMPLE_STMT(Stmt, "SELECT NULL");
+
+  CHECK_STMT_RC(Stmt, SQLGetStmtAttr(Stmt, SQL_ATTR_APP_ROW_DESC, &Ard, 0, NULL));
+  CHECK_DESC_RC(Ard, SQLSetDescField(Ard, 1, SQL_DESC_TYPE, (SQLPOINTER)SQL_NUMERIC, 0));
+  CHECK_STMT_RC(Stmt, SQLFetch(Stmt));
+  CHECK_STMT_RC(Stmt, SQLFreeStmt(Stmt, SQL_CLOSE));
+
+  return OK;
+}
+
+
 MA_ODBC_TESTS my_tests[]=
 {
   {t_bug32420, "t_bug32420"},
@@ -1164,6 +1180,7 @@ MA_ODBC_TESTS my_tests[]=
   {t_odbc77, "t_odbc-77-analyze_table"},
   {t_odbc78, "t_odbc-78-sql_no_data"},
   {t_odbc73, "t_odbc-73-bin_collation"},
+  {t_odbc134, "t_odbc-134-fetch_unbound_null"},
   {NULL, NULL}
 };