Using Gradle's new file permission API is implemented in a way that prevents removal of the old API

[jbartok]

Addressing issue

• Gradle plugin uses to-be-deprecated API for getting and setting file permissions #37878

resulted in changes in this code:

• spring-boot/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootArchiveSupport.java

  Line 153 in 793aca6

  return getMode(copySpec, "getDirPermissions", copySpec::getDirMode);

The problem with the change is that it should call the fallback code (the old API methods, like copySpec::getDirMode and copySpec::getFileMode) also via reflection, because as it is now, we are unabled to remove them (they've been deprecated for a while now in Gradle).

We intend to do the removal in Gradle 9, which is in the near future and this would completely prevent us from doing so.

[wilkinsona]

This is similar to #38164. The problem's due to the use of a method reference. When the method's absent, this results in a failure at runtime even if the method isn't called. Rather than using reflection, we should be able to avoid the problem by using a lambda instead of the method reference.

[cms04]

As far as I understand issue #39431, using lambdas instead of method references might not solve the problem.

But maybe that's a mistake in my thinking because the fallback.get() statement will never be reached when the method is executed with Gradle 9.0 (unlike the method call to configuration.licenseKey(licenseKey) mentioned in the other issue).

In #41606 I implemented a solution with reflection (as suggested by @jbartok). This is the most fail-safe solution in my opinion.

[wilkinsona]

But maybe that's a mistake in my thinking because the fallback.get() statement will never be reached

Yes, that's the case. The supplier will never be called so the absence of the method does not matter.

[jbartok]

I would think that even if the fallback lambda is never called, once you upgrade to a Gradle version's API, that no longer has the method from the fallback, you would not be able to compile your code. That's why I suggested using reflection.