Fixed append array issue https://github.com/mikefarah/yq/issues/874

pkg/yqlib/operator_add.go

@@ -15,11 +15,27 @@ func createAddOp(lhs *ExpressionNode, rhs *ExpressionNode) *ExpressionNode {
 }
 
 func addAssignOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
+	lhs, err := d.GetMatchingNodes(context, expressionNode.Lhs)
+	if err != nil {
+		return Context{}, err
+	}
+
 	assignmentOp := &Operation{OperationType: assignOpType}
-	assignmentOp.UpdateAssign = true
+	valueOp := &Operation{OperationType: valueOpType}
-	selfExpression := &ExpressionNode{Operation: &Operation{OperationType: selfReferenceOpType}}
+
-	assignmentOpNode := &ExpressionNode{Operation: assignmentOp, Lhs: expressionNode.Lhs, Rhs: createAddOp(selfExpression, expressionNode.Rhs)}
+	for el := lhs.MatchingNodes.Front(); el != nil; el = el.Next() {
-	return d.GetMatchingNodes(context, assignmentOpNode)
+		candidate := el.Value.(*CandidateNode)
+		valueOp.CandidateNode = candidate
+		valueExpression := &ExpressionNode{Operation: valueOp}
+
+		assignmentOpNode := &ExpressionNode{Operation: assignmentOp, Lhs: valueExpression, Rhs: createAddOp(valueExpression, expressionNode.Rhs)}
+
+		_, err = d.GetMatchingNodes(context, assignmentOpNode)
+		if err != nil {
+			return Context{}, err
+		}
+	}
+	return context, nil
 }
 
 func toNodes(candidate *CandidateNode) []*yaml.Node {

pkg/yqlib/operator_add_test.go

@@ -14,6 +14,14 @@ var addOperatorScenarios = []expressionScenario{
 			"D0, P[1 a], (!!int)::3\n",
 		},
 	},
+	{
+		skipDoc:    true,
+		document:   "array: [1]\narray2: [2]",
+		expression: ".array += .array2",
+		expected: []string{
+			"D0, P[], (doc)::array: [1, 2]\narray2: [2]\n",
+		},
+	},
 	{
 		skipDoc:    true,
 		document:   `{}`,

pkg/yqlib/operator_assign.go

@@ -8,6 +8,9 @@ func assignUpdateOperator(d *dataTreeNavigator, context Context, expressionNode
 	var rhs Context
 	if !expressionNode.Operation.UpdateAssign {
 		rhs, err = d.GetMatchingNodes(context.ReadOnlyClone(), expressionNode.Rhs)
+		if err != nil {
+			return Context{}, err
+		}
 	}
 
 	for el := lhs.MatchingNodes.Front(); el != nil; el = el.Next() {