Add missing check for array out of bounds

interpreter.go

@@ -392,7 +392,7 @@ func (i *interpreter) evaluate(a ast.Node, tc tailCallStatus) (value, error) {
 				return nil, err
 			}
 			// TODO(https://github.com/google/jsonnet/issues/377): non-integer indexes should be an error
-			return e.evaluateTailCall(target.elements[int(indexInt.value)], tc)
+			return target.index(e, int(indexInt.value), tc)
 
 		case *valueString:
 			indexInt, err := e.getNumber(index)

testdata/array_out_of_bounds.golden

@@ -0,0 +1,10 @@
+RUNTIME ERROR: Index 0 out of bounds, not within [0, 0)
+-------------------------------------------------
+	testdata/array_out_of_bounds:1:1-6	$
+
+[][0]
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/array_out_of_bounds.jsonnet

@@ -0,0 +1 @@
+[][0]

testdata/array_out_of_bounds2.golden

@@ -0,0 +1,10 @@
+RUNTIME ERROR: Index 3 out of bounds, not within [0, 3)
+-------------------------------------------------
+	testdata/array_out_of_bounds2:1:1-11	$
+
+[1,2,3][3]
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/array_out_of_bounds2.jsonnet

@@ -0,0 +1 @@
+[1,2,3][3]

testdata/array_out_of_bounds3.golden

@@ -0,0 +1,10 @@
+RUNTIME ERROR: Index -1 out of bounds, not within [0, 0)
+-------------------------------------------------
+	testdata/array_out_of_bounds3:1:1-7	$
+
+[][-1]
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/array_out_of_bounds3.jsonnet

@@ -0,0 +1 @@
+[][-1]

testdata/array_out_of_bounds4.golden

@@ -0,0 +1,10 @@
+RUNTIME ERROR: Index 42 out of bounds, not within [0, 3)
+-------------------------------------------------
+	testdata/array_out_of_bounds4:1:1-12	$
+
+[1,2,3][42]
+
+-------------------------------------------------
+	During evaluation	
+
+

testdata/array_out_of_bounds4.jsonnet

@@ -0,0 +1 @@
+[1,2,3][42]

value.go

@@ -200,6 +200,13 @@ type valueArray struct {
 	elements []potentialValue
 }
 
+func (arr *valueArray) index(e *evaluator, index int, tc tailCallStatus) (value, error) {
+	if 0 <= index && index < arr.length() {
+		return e.evaluateTailCall(arr.elements[index], tc)
+	}
+	return nil, e.Error(fmt.Sprintf("Index %d out of bounds, not within [0, %v)", index, arr.length()))
+}
+
 func (arr *valueArray) length() int {
 	return len(arr.elements)
 }