to_xml Method Behavior is Inconsistent

[0arm0]

The to_xml method in the Atmospheric::Export::Iso25331975::GroupBase class exhibits inconsistent behavior. The following scenarios were tested:

Calling the Class Method to_xml with an Object:

obj = Atmospheric::Export::Iso25331975::GroupBase.new
Atmospheric::Export::Iso25331975::GroupBase.to_xml(obj)
Result: Returns "<test/>".

Calling the Instance Method to_xml:

Atmospheric::Export::Iso25331975::GroupBase.new.to_xml
Result: Returns nil.

This behavior is unexpected because the instance method to_xml should ideally provide serialized XML output for the object's data. However, it returns nil, while the class method returns an arbitrary XML string ("").

Steps to Reproduce:

Create an instance of GroupBase:

obj = Atmospheric::Export::Iso25331975::GroupBase.new

Test the class method to_xml:

Atmospheric::Export::Iso25331975::GroupBase.to_xml(obj)
Test the instance method to_xml:

Atmospheric::Export::Iso25331975::GroupBase.new.to_xml
Expected Behavior:

The to_xml method (either class or instance) should return consistent XML serialization for the object's data.
If the to_xml method is not fully implemented, it should raise an appropriate error or return a meaningful placeholder, not nil.
Actual Behavior:

The instance method to_xml returns nil.
The class method to_xml returns a static placeholder XML ("").

[ronaldtse]

@0arm0 can you provide more information on how Atmospheric::Export::Iso25331975::GroupBase is defined? Is it inherited from Lutaml::Model::Serializable? Does it have attributes defined?

As you know Lutaml::Model::Serializable provides serialization methods on instances, not classes.

I don't know on top of my head whether is a valid use case to apply serialization methods to classes directly. (Probably?)

[0arm0]

@0arm0 can you provide more information on how Atmospheric::Export::Iso25331975::GroupBase is defined? Is it inherited from Lutaml::Model::Serializable? Does it have attributes defined?

As you know Lutaml::Model::Serializable provides serialization methods on instances, not classes.

I don't know on top of my head whether is a valid use case to apply serialization methods to classes directly. (Probably?)

@ronaldtse here is how I am using Lutaml::Model::Serializable in my class.
This could be just a workaround to apply serialization methods to classes directly incase the instance method doesnt work. Just like my case.

[ronaldtse]

@0arm0 I would suggest not using hash as an attribute type but directly applying attributes to the values, and inner Lutaml::Model::Serializable classes as intermediary objects.