XmlMapper.copy() doesn't properly copy internal configurations

[gtrog]

Affected version: all versions (up to jackson-dataformat-xml-2.9.0.pr3)

Currently, if you create an instance of XmlMapper and register a module with it, any copies of that mapper will not contain the registered module. This behavior is different from the behavior of ObjectMapper, which retains all other configurations, such as modules, serialization/deserialization configs, etc.

final XmlMapper mapper = new XmlMapper();
mapper.registerModule(new JaxbAnnotationModule());

final XmlMapper mapperWithoutModule = mapper.copy();

I think this could be easily resolved by following the same copy-constructor pattern that ObjectMapper uses to copy itself, and then just invoking super's constructor in XmlMapper's copy constructor.

I'll have a PR up shortly.

[cowtowncoder]

Thank you for reporting this: yes, copy() should retain module settings.

I added one important comment; I think serializer provider does need to be copied. Otherwise LGTM.

[cowtowncoder]

Thank you! I also backported this in 2.8, to be included in 2.8.9.