Stefano Cordio

Would it be really necessary to have a separate library on top of `assertj-core` or could we do something like JUnit did in [`Assertions.kt`](https://github.com/junit-team/junit5/blob/main/junit-jupiter-api/src/main/kotlin/org/junit/jupiter/api/Assertions.kt)?

Likely, both `AbstractObjectArrayAssert::extracting` and `AbstractIterableAssert::extracting` are affected. We should add corresponding test cases in the `assertj-core-kotlin` test module.

Based on the analysis done today with @patrickwalter214 at [Hack Commit Push Winterthur](https://winterthur2025.hack-commit-pu.sh/), we identified two possible changes to enhance Kotlin compatibility without major breaks of Java use cases: *...

> Remove `extracting(Function)` variants, as `extracting(ThrowingExtractor)` can cover them too This decision turned out to be not a good one, from a compatibility perspective, and will be reconsidered at https://github.com/assertj/assertj/pull/3854#discussion_r2549110660.

This can also be relevant for `ItemReader` and `ItemProcessor`.

> While [`PropertyExtractingDelegatingItemWriter`](https://docs.spring.io/spring-batch/docs/current/api/org/springframework/batch/item/adapter/PropertyExtractingDelegatingItemWriter.html) seems to be a solution After some experimentation, `PropertyExtractingDelegatingItemWriter` is not a suitable solution for my use case, as it attempts to invoke the delegate method (in...

> This can also be relevant for `ItemReader` and `ItemProcessor`. After checking better, `CompositeItemReader` and `CompositeItemProcessor` have a different delegation pattern compared to `CompositeItemWriter`, and I don't see the usefulness...

Moving the issue to the core project as it doesn't seem related to the generator.

Thanks for reporting it, @jamesmudd! We'll look into it and get back to you.

The registered comparator is for the `double` primitive type and not for `java.lang.Double`: ``` double -> DoubleComparator[precision=5.0E-4] ``` The Kotlin example behaves like the following Java code, which also fails:...