Fixed potential npe

cmd/read_test.go

@@ -617,6 +617,27 @@ pointer: *value-pointer`
 	test.AssertResult(t, expectedOutput, result.Output)
 }
 
+func TestReadMergeAnchorsExplodeMissingCmd(t *testing.T) {
+	content := `a:
+  <<: &anchor
+  c: d
+  e: f
+`
+	filename := test.WriteTempYamlFile(content)
+	defer test.RemoveTempYamlFile(filename)
+
+	cmd := getRootCommand()
+	result := test.RunCmd(cmd, fmt.Sprintf("read -X %s", filename))
+	if result.Error != nil {
+		t.Error(result.Error)
+	}
+	expectedOutput := `a:
+  c: d
+  e: f
+`
+	test.AssertResult(t, expectedOutput, result.Output)
+}
+
 func TestReadMergeAnchorsExplodeKeyCmd(t *testing.T) {
 	content := `name: &nameField Mike
 *nameField: Great Guy`

cmd/utils.go

@@ -163,6 +163,9 @@ func setIfNotThere(node *yaml.Node, key string, value *yaml.Node) {
 }
 
 func applyAlias(node *yaml.Node, alias *yaml.Node) {
+	if alias == nil {
+		return
+	}
 	for index := 0; index < len(alias.Content); index = index + 2 {
 		keyNode := alias.Content[index]
 		log.Debugf("applying alias key %v", keyNode.Value)
@@ -185,12 +188,14 @@ func explodeNode(node *yaml.Node) error {
 		return nil
 	case yaml.AliasNode:
 		log.Debugf("its an alias!")
-		node.Kind = node.Alias.Kind
-		node.Style = node.Alias.Style
-		node.Tag = node.Alias.Tag
-		node.Content = node.Alias.Content
-		node.Value = node.Alias.Value
-		node.Alias = nil
+		if node.Alias != nil {
+			node.Kind = node.Alias.Kind
+			node.Style = node.Alias.Style
+			node.Tag = node.Alias.Tag
+			node.Content = node.Alias.Content
+			node.Value = node.Alias.Value
+			node.Alias = nil
+		}
 		return nil
 	case yaml.MappingNode:
 		for index := 0; index < len(node.Content); index = index + 2 {