Make buildNumber optional

[aslakhellesoy]

Description

Make buildNumber an optional field.

Motivation & context

The TypeScript definition of CiEnvironment incorrectly declared the field as mandatory, but at runtime it may be optional.

Type of change

• Breaking change (will cause existing functionality to not
  work as expected)

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• I have added tests to cover my changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

[mpkorstanje]

So what about messages? It is required there.

[aslakhellesoy]

When we added the field in 17.0.0 it was a mistake to define this field as mandatory.

It was a mistake because consumers have to handle previous versions of messages where the field would always be absent. As a general rule, we should always declare new fields as not required in order to be able to handle older versions.

So I propose:

• We make a new messages release where the field is optional. It's debatable whether it is a bugfix or a breaking change - I'm leaning towards bugfix in this case.
• I update this PR to make it optional here too.

It's a real shame jsonschema2pojo doesn't generate Optional getters for non-required fields. There is an open PR for it: joelittlejohn/jsonschema2pojo#1057. We could fork and release our own maven package, or we could abandon it altogether and use custom code generation like we do for TypeScript, Go and Ruby. I think maybe the latter.

WDYT?

[aurelien-reeves]

Well, I don't know with java. But in the schema, and in js and ruby and go implementation, the build number is not mandatory in messages

[aslakhellesoy]

You're right @aurelien-reeves - it's not required. What made you think it was required @mpkorstanje?

[mpkorstanje]

Ah. My bad. That should have been a question, not an assertion.

So we're good.

[mpkorstanje]

It's a real shame jsonschema2pojo doesn't generate Optional getters for non-required fields. There is an open PR for it: joelittlejohn/jsonschema2pojo#1057. We could fork and release our own maven package, or we could abandon it altogether and use custom code generation like we do for TypeScript, Go and Ruby. I think maybe the latter.

One thing at a time.

[aslakhellesoy]

@mpkorstanje I wasn't quite ready with this PR, ref my suggestion above to make buildNumber optional. Please don't release this until I have fixed that.

[mpkorstanje]

Not sure what you mean. I did see buildNumber?: string so I assume you made it optional.

[aslakhellesoy]

You're right - ignore me. Getting my wires crossed.