unmarshal xml to []structs with xml.Name

Problem

I need to unmarshal XML from an 3rd party application to my GO struct.

what i tried

I created structs and am able to generate identical XML from my code.
@see TestMetaData_Marshal

ValidXML

i simplified the xml for this example:

<Parent>
	<Name>tic.TEST</Name>
	<MetaData>
		<LawFormID Type="129" DefinedSize="3">DOO</LawFormID>
		<FirmUQ Type="129" DefinedSize="15">BARTOG</FirmUQ>
		<FirmDescription Type="200" DefinedSize="100">Bartog d.o.o. Trebnje</FirmDescription>
	</MetaData>
</Parent>

Structs

my corresponding structs are the following.
NOTE: i created a struct for MetaData though i would prefer to NOT use one (due json, yaml)

type Parent struct {
	Name string
	MetaData []Node `xml:"MetaData>any"`
}

type Node struct {
	XMLName     xml.Name // this allows custom node names
	Type        int      `xml:"Type,attr,omitempty"`
	DefinedSize int      `xml:"DefinedSize,attr,omitempty"`
	Text        string   `xml:",chardata"` // required at some places, cannot omit
}

@TestMetadata_Marshal

func TestMetaData_Marshal(t *testing.T) {
	parent := Parent{
		Name: "tic.TEST",
		MetaData: []Node{
			{
				XMLName: xml.Name{
					Local: "LawFormID",
				},
				Text:        "DOO",
				Type:        129,
				DefinedSize: 3,
			}, {
				XMLName: xml.Name{
					Local: "FirmUQ",
				},
				Text:        "BARTOG",
				Type:        129,
				DefinedSize: 15,
			}, {
				XMLName: xml.Name{
					Local: "FirmDescription",
				},
				Text:        "Bartog d.o.o. Trebnje",
				Type:        200,
				DefinedSize: 100,
			},
		}, // \MetaData
	}
	HaveXML := XML(parent)
	fmt.Println(HaveXML)
	if ValidXML != HaveXML {
		t.Error(fmt.Errorf("marshaled XML did not match. Have: %v", HaveXML))
	}
}

Unmarshal

this is where the troubles begin; the test func is trivial; result is that no entries in MetaData are available.
I tried a lot of different tags, also tried creating an own MetaData struct containing Items []Node

func TestUnmarshal() {
	var parent Parent
	err := xml.Unmarshal([]byte(ValidXML), &parent)
	if err != nil {
		fmt.Println(err)
		return
	}
	HaveXML := XML(parent)
	if ValidXML == HaveXML {
		fmt.Println("\tmarshaled XML is Valid")
	} else {
		fmt.Printf("\tmarshaled XML did not match. Have:\n%v\n", HaveXML)
	}
}

go play (turned tests into 'normal' funcs

https://goplay.tools/snippet/kWS29HR7O9t

Question

Is it not possible to do this in go&xml?
Iff it IS possible, what am i doing wrong?

The problem is that any is not the tag name, it's an option. So when using it, you have to put a comma before it, e.g. xml:",any".

I don't think you can combine it with >, so create a separate MetaData struct:

type Parent struct {
	Name     string
	MetaData MetaData `xml:"MetaData"`
}

type MetaData struct {
	Nodes []Node `xml:",any"`
}

With this refactoring your example works and outputs (try it on the Go Playground):

=== TestMarshal
<Parent>
	<Name>tic.TEST</Name>
	<MetaData>
		<LawFormID Type="129" DefinedSize="3">DOO</LawFormID>
		<FirmUQ Type="129" DefinedSize="15">BARTOG</FirmUQ>
		<FirmDescription Type="200" DefinedSize="100">Bartog d.o.o. Trebnje</FirmDescription>
	</MetaData>
</Parent>
	marshaled XML is Valid
=== TestUnmarshal
	marshaled XML is Valid