Immutable configuration properties not shown by Actuator

[AlexFalappa]

From my initial test drive of the freshly released Spring Boot 2.2.0.RELEASE it seems that @ConfigurationProperties beans declared as immutable with @ConstructorBinding show up empty in the Actuator configprops endpoint.
Example:

"ftp-af.FtpProperties": {
  "prefix": "ftp",
  "properties": {}
}

The beans are however correctly bound and their use in other beans is not impacted.

Normal, mutable beans are correctly displayed with their attributes.
Example:

"ftp-af.FtpProperties": {
  "prefix": "ftp",
  "properties": {
    "host": "andromeda",
    "dir": "/path/to/files",
    "user": "JohnSmith",
    "port": 2121,
    "passw": "Unknown"
  }
}

[snicoll]

Oops. Thanks for the report!

[rhamedy]

@snicoll is this feasible for contribution?

I have used actuator endpoint before; however, I don't know how it works under the hood. I am curious how complicated is this task? If open for contribution, I would love to give it a shot. I would appreciate some direction in the form of guidance, previous issues/PRs I could look into, materials, classes, etc.

[snicoll]

@rhamedy it's really hard to answer such question without looking at the actual problem and often we have the solution by the time we're experimenting. This one is extra special as it's assigned to 2.2.1 which we intend to release relatively soon-ish and I really would like to get that fixed.

If you have time short term, I believe the problem is this method that serializes the content of the configuration properties instance. For some reason that doesn't work if there isn't a setter? Wild guess, I haven't looked at it in more details.

If you want to contribute, we have an ideal-for-contribution label on the issue tracker.

[polarbear567]

@snicoll I think we can use other conversion methods here.

[rhamedy]

Thank you both (snicoll and wilkinsona) for the comment. If not mistaken, @polarbear567 seems to have already made a PR for this issue #18659. If the PR is not related, then apologies for linking it.

I think snicoll made some good points about complexity and urgency. It would be best for me to await another opportunity to work on Actuator 🤞

[snicoll]

I've started to hack on something in 353a30f and I've discovered some potential improvements in constructor binding in the process (#18685). I have something somewhat satisfactory except that nested types are not processed. It looks like Jackson decides that there is nothing do as there are no properties or something like that? There is a test failing on that commit.