This is an interesting consequence of fixing org.gradle.native handling.

Before 8.8 Gradle ignored org.gradle.native flag, which was basically a bug. That was fixed with #28021 in 8.8. Unfortunately our ForkingTestClassProcessor had also a performance optimization that disabed loading native services in workers, and it did that by setting org.gradle.native=false: that system property is not set anymore with #28401.
That worked fine before with Gradle <= 8.7, since Gradle <= 8.7 just ignored org.gradle.native flag.

But now if you use Gradle 8.7 wrapper that still sets org.gradle.native=false system property and you test Gradle 8.8-rc-1, 8.8-rc-1 build will correctly handle that flag and disable the native services -> so env. variables won't be passed in the build.

To fix that one of these options will work:

1. Use Gradle 8.8-rc-1 wrapper
2. Or do System.clearProperty("org.gradle.native") somewhere at the start of your test
3. Or do System.setProperty("org.gradle.native", "true") somewhere at the start of your test
4. Or in your build script do

tasks.withType<Test>().configureEach {
  systemProperty("org.gradle.native", true)
}

Ah thank you for the explanation, that makes sense! For now we will set the property and presumably once we upgrade our main gradle version to 8.8 we can take it back out.

Thanks for the workaround with setting org.gradle.native. Not sure if this is related but in 8.7 if the env var has the value of an empty string withEnvironment(Map.of("FOO",""), the environment var under the gradle runner will exist with an empty string value. In 8.8-rc-1, it will not be set so System.getenv("FOO") will return null

Fixed with #29218, we reverted the behaviour of org.gradle.native flag.

I also tested withEnvironment(Map.of("FOO","") example and it seems empty value is passed to the process.