Fixed multiply string by negative number panic #2211

Author: mikefarah

pkg/yqlib/operator_multiply.go

@@ -153,6 +153,8 @@ func repeatString(lhs *CandidateNode, rhs *CandidateNode) (*CandidateNode, error
 	count, err := parseInt(intNode.Value)
 	if err != nil {
 		return nil, err
+	} else if count < 0 {
+		return nil, fmt.Errorf("Cannot repeat string by a negative number (%v)", count)
 	}
 	target.Value = strings.Repeat(stringNode.Value, count)
 

pkg/yqlib/operator_multiply_test.go

@@ -201,6 +201,13 @@ var multiplyOperatorScenarios = []expressionScenario{
 			fmt.Sprintf("D0, P[], (!!str)::%s\n", strings.Repeat("banana", 4)),
 		},
 	},
+	{
+		description:   "Multiply string X by negative int",
+		skipDoc:       true,
+		document:      `n: -4`,
+		expression:    `"banana" * .n`,
+		expectedError: "Cannot repeat string by a negative number (-4)",
+	},
 	{
 		description: "Multiply int node X string",
 		document: `n: 4