Gradle: Add buildSrc to the sample project

[MartyIX]

This is an attempt to add buildSrc for apache/logging-log4j2#3822 to address apache/logging-log4j2#3779 (comment).

However, I'm not sure why but 2.25.1 works here but not for my personal project. Meaning, I did not reproduce what I wrote here apache/logging-log4j2#3779 (comment).

Any thought @ppkarwasz please?

Testing

# Fails (as expected)
export LOG4J_VERSION=2.25.0; ./gradlew :log4j-samples-gradle-metadata:build # Run from the repo's root directory!

# Works (but `buildSrc` project should report an error-prone version error but it does not.
export LOG4J_VERSION=2.25.1; ./gradlew :log4j-samples-gradle-metadata:build

Resources

https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:sharing_logic_via_convention_plugins

[ppkarwasz]

Hi @MartyIX,

Thanks again for digging into this — even negative results are valuable, as they help us identify what might be missing in the test project.

Based on Copilot’s analysis, the error message you encountered doesn't appear to originate from Gradle itself, but rather from the Spring Dependency Management Plugin.

Would you be able to try applying the plugin to the log4j-samples-gradle-metadata project to see if it reproduces the issue? Ideally, it would be great if the problem can be triggered without introducing an additional buildSrc project.

You can apply the plugin like this:

id "io.spring.dependency-management" version "1.1.7"

If that reproduces the error, could you also check whether switching to the native Gradle platform support (via platform() or enforcedPlatform()) serves as a viable workaround in your own project?

[MartyIX]

That's great insight! I opened #351 which reports the error.

I'm closing this PR.