[JENKINS-44892] DescribableModel customization

[jglick]

JENKINS-44892: API permitting plugins which define structs to fine-tune how their surface form is presented, particularly in Pipeline Groovy.

[daspilker]

This change would only have limited effect on Job DSL. It is not possible to pass arbitrary arguments to DescribableModel.instantiate as it is possible in Pipeline (from what I understand). Job DSL does strict checks to allow only DescribableParameters to be passed as arguments for instantiation. The change will help to provide better backwards-compatibility like for JENKINS-51638, but it will not be possible to mitigate a removed DataBoundSetter. IMHO this change provides a missing hook, but does not address all use cased mentioned in JENKINS-44892, especially I do not see how the GerritTrigger case could be handled for Job DSL.

[jglick]

It is not possible to pass arbitrary arguments to DescribableModel.instantiate as it is possible in Pipeline (from what I understand). Job DSL does strict checks to allow only DescribableParameters to be passed as arguments for instantiation.

I think if JENKINS-33217 were implemented properly (inside DescribableModel.instantiate, after processing by CustomDescribableModel) this code could be deleted from job-dsl and customizations such as the hypothetical GerritTrigger example could be supported by workflow-cps and job-dsl equally.