Fixed issue on creating objects using []

pkg/yqlib/operator_traverse_path.go

@@ -127,9 +127,16 @@ func traverseArrayIndices(context Context, matchingNode *CandidateNode, indicesT
 	node := matchingNode.Node
 	if node.Tag == "!!null" {
 		log.Debugf("OperatorArrayTraverse got a null - turning it into an empty array")
-		// auto vivification, make it into an empty array
+		// auto vivification
 		node.Tag = ""
 		node.Kind = yaml.SequenceNode
+		//check that the indices are numeric, if not, then we should create an object
+		if len(indicesToTraverse) != 0 {
+			_, err := strconv.ParseInt(indicesToTraverse[0].Value, 10, 64)
+			if err != nil {
+				node.Kind = yaml.MappingNode
+			}
+		}
 	}
 
 	if node.Kind == yaml.AliasNode {

pkg/yqlib/operator_traverse_path_test.go

@@ -43,6 +43,13 @@ var traversePathOperatorScenarios = []expressionScenario{
 			"D0, P[0 0 0], (!!int)::1\n",
 		},
 	},
+	{
+		skipDoc:    true,
+		expression: `.["cat"] = "thing"`,
+		expected: []string{
+			"D0, P[], ()::cat: thing\n",
+		},
+	},
 	{
 		description: "Simple map navigation",
 		document:    `{a: {b: apple}}`,