Reject fractional array.fetch indices

Author: mgomes

vibes/execution_members_array_query.go

@@ -1,6 +1,9 @@
 package vibes
 
-import "fmt"
+import (
+	"fmt"
+	"math"
+)
 
 func arrayMemberQuery(property string) (Value, error) {
 	switch property {
@@ -220,6 +223,9 @@ func arrayMemberQuery(property string) (Value, error) {
 			if err != nil {
 				return NewNil(), fmt.Errorf("array.fetch index must be integer")
 			}
+			if args[0].Kind() == KindFloat && math.Trunc(args[0].Float()) != args[0].Float() {
+				return NewNil(), fmt.Errorf("array.fetch index must be integer")
+			}
 			arr := receiver.Array()
 			if index >= 0 && index < len(arr) {
 				return arr[index], nil

vibes/runtime_test.go

@@ -3659,6 +3659,11 @@ func TestMethodErrorHandling(t *testing.T) {
 			script: `def run [1, 2, 3].fetch("1") end`,
 			errMsg: "index must be integer",
 		},
+		{
+			name:   "array.fetch with fractional float index",
+			script: `def run [1, 2, 3].fetch(1.5) end`,
+			errMsg: "index must be integer",
+		},
 		{
 			name: "array.count with argument and block",
 			script: `def run()