Provide configuration property metadata for binding to Map<String, RichType> and List<RichType>

One example of such a Map is in Spring Cloud stream. As things stand, there’s no metadata for any of the properties on BindingProperties. I think it would be interesting to explore the possibility of providing metadata for those properties, perhaps using a wildcard for the key in the map:

spring.cloud.stream.bindings.*.content-type
spring.cloud.stream.bindings.*.destination
spring.cloud.stream.bindings.*.group
…

For this to be useful, we’d need a corresponding enhancement in each of the IDE plugins.

[snicoll]

I can’t speak for Eclipse but IJ has support for this for ages on .properties. There isn’t for yaml at the moment though. To be clear, we’re now considering this with higher priority given the potential binding change.

[wilkinsona]

The lack of this metadata allowed the mistake that @dreis2211 has fixed in this pull request to slip through. Our Asciidoctor extension only validates maps on a best-effort basis. The prefix, spring.security.saml2.relyingparty.registration, matched and there’s no metadata to tell it what properties each entry in the map may have so it was unable to detect and report the error.