XML module not registered correctly when setting a custom `SerializerFactory`

[SimonCockx]

I'm using a custom SerializerFactory as follows.

ObjectMapper mapper = new XmlMapper().setSerializerFactory(MySerializerFactory.INSTANCE);

I noticed that in the constructor of XmlMapper, the default XML_MODULE is registered, which also configures the SerializerFactory. Since I'm overriding it after constructing, this configuration is lost, resulting in different behaviour, which is very confusing.

I currently don't see any way for registering my custom SerializerFactory before the XML_MODULE is registered. Is this intended? It seems error-prone.

My current workaround:

ObjectMapper mapper = new XmlMapper((JacksonXmlModule) null)
    .setSerializerFactory(RosettaSerialiserFactory.INSTANCE)
    .registerModule(new JacksonXmlModule());

[cowtowncoder]

I think that overriding of SerializerFactory is very rare thing, this is probably the first time I've heard users doing that. So I don't think the problem here was anticipated.

It might help if I understood your use case better: why are you overriding SerializerFactory?

[SimonCockx]

See my comment in https://github.com/FasterXML/jackson-dataformat-xml/issues/676#issuecomment-2438049500.

At the moment I'm using a custom SerializerFactory to "hack in" some solutions to that issue. :)

[cowtowncoder]

Ah ok. Yes, we should make it possible to configure SerializerFactory even with XML module. Right now I am bit overloaded with Jackson work so I may not have time to work on this, BUT, if you had time to maybe propose a pr, I'd make sure find time to review and help with it.

Without remembering full details, I suspect JacksonXmlModule should expose configurability of SerializerFactory -- it seems to be passed to XmlSerializerProvider (sub-class of default SerializerProvider) as it's, well, required.

But I guess I am not sure which aspects of SerializerFactory configuration you are referring to? No custom factory is used, and although some set methods probably set things on that factory indirectly, I don't see immediate paths.

[SimonCockx]

But I guess I am not sure which aspects of SerializerFactory configuration you are referring to? No custom factory is used, and although some set methods probably set things on that factory indirectly, I don't see immediate paths.

Just to clarify the issue: the JacksonXmlModule adds the following two modifiers:

context.addBeanSerializerModifier(new XmlBeanSerializerModifier());
context.addBeanDeserializerModifier(new XmlBeanDeserializerModifier(_cfgNameForTextElement));

When setting the SerializerFactory after this module is registered, these modifiers are lost.

BUT, if you had time to maybe propose a pr, I'd make sure find time to review and help with it.

Thanks. I'll see if I find a moment, but can't make any promise either. :)

[cowtowncoder]

Ah. Yes, flow of configuration gets bit hairy, since SerializerFactory is amongst oldest extant abstractions and its configuration was not as well-thought-out as newer additions. This does explain the problem well fwtw.

And yes, pr would be great but we all have limited time so I take whatever I can get. :)

[cowtowncoder]

I did #680 and I think it might be the best small thing I can do; will merge.