Handle "IS NULL" constraints on virtual table scans. IS NULL constraints are not passed to the virtual table layer. Ticket #2759. (CVS 4523)

FossilOrigin-Name: 7027368c15b3270a139bea5612d7c03c2288dcc4

test/vtab1.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this file is creating and dropping virtual tables.
 #
-# $Id: vtab1.test,v 1.47 2007/10/09 08:29:33 danielk1977 Exp $
+# $Id: vtab1.test,v 1.48 2007/11/05 05:12:53 danielk1977 Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -946,5 +946,35 @@ do_test vtab1.12-6 {
   execsql { SELECT * FROM c }
 } {3 G H}
 
+# At one point (ticket #2759), a WHERE clause of the form "<column> IS NULL"
+# on a virtual table was causing an assert() to fail in the compiler.
+#
+# "IS NULL" clauses should not be passed through to the virtual table
+# implementation. They are handled by SQLite after the vtab returns it's
+# data.
+#
+do_test vtab1.13-1 {
+  execsql { 
+    SELECT * FROM echo_c WHERE a IS NULL 
+  }
+} {}
+do_test vtab1.13-2 {
+  execsql { 
+    INSERT INTO c VALUES(NULL, 15, 16);
+    SELECT * FROM echo_c WHERE a IS NULL 
+  }
+} {{} 15 16}
+do_test vtab1.13-3 {
+  execsql { 
+    INSERT INTO c VALUES(15, NULL, 16);
+    SELECT * FROM echo_c WHERE b IS NULL 
+  }
+} {15 {} 16}
+do_test vtab1.13-3 {
+  execsql { 
+    SELECT * FROM echo_c WHERE b IS NULL AND a = 15;
+  }
+} {15 {} 16}
+
 unset -nocomplain echo_module_begin_fail
 finish_test