fix - null as primary key is allowed in an insert statement with auto_increment

go/vt/sqlparser/analyzer.go

@@ -47,6 +47,15 @@ func IsValue(node ValExpr) bool {
 	return false
 }
 
+// IsNull returns true if the ValExpr is nil.
+func IsNull(node ValExpr) bool {
+	switch node.(type) {
+	case *NullVal:
+		return true
+	}
+	return false
+}
+
 // HasINClause returns true if any of the conditions has an IN clause.
 func HasINClause(conditions []BoolExpr) bool {
 	for _, node := range conditions {

go/vt/tabletserver/endtoend/nocache_case_test.go

@@ -617,6 +617,30 @@ func TestNocacheCases(t *testing.T) {
 				framework.TestQuery("commit"),
 			},
 		},
+		&framework.MultiCase{
+			Name: "insert with null auto_increment",
+			Cases: []framework.Testable{
+				framework.TestQuery("alter table vitess_e auto_increment = 1"),
+				framework.TestQuery("begin"),
+				&framework.TestCase{
+					Query: "insert /* auto_increment */ into vitess_e(eid, name, foo) values (NULL, 'aaaa', 'cccc')",
+					Rewritten: []string{
+						"insert /* auto_increment */ into vitess_e(eid, name, foo) values (null, 'aaaa', 'cccc') /* _stream vitess_e (eid id name ) (null 1 'YWFhYQ==' )",
+					},
+					RowsAffected: 1,
+				},
+				framework.TestQuery("commit"),
+				&framework.TestCase{
+					Query: "select * from vitess_e",
+					Result: [][]string{
+						{"1", "1", "aaaa", "cccc"},
+					},
+				},
+				framework.TestQuery("begin"),
+				framework.TestQuery("delete from vitess_e"),
+				framework.TestQuery("commit"),
+			},
+		},
 		&framework.MultiCase{
 			Name: "insert with number default value",
 			Cases: []framework.Testable{

go/vt/tabletserver/planbuilder/dml.go

@@ -494,7 +494,7 @@ func getInsertPKValues(pkColumnNumbers []int, rowList sqlparser.Values, tableInf
 				return nil, errors.New("column count doesn't match value count")
 			}
 			node := row[columnNumber]
-			if !sqlparser.IsValue(node) {
+			if !sqlparser.IsNull(node) && !sqlparser.IsValue(node) {
 				return nil, nil
 			}
 			var err error