On Wed, 7 Aug 2024 12:13:55 GMT, Jaikiran Pai <j...@openjdk.org> wrote:
>> I was able to reproduce this `NoClassDefFoundError` in this new test >> locally. I will take a look to see if I can figure out what's going on. > > I looked into this locally and this is a (known) bug in jtreg > https://bugs.openjdk.org/browse/CODETOOLS-7902847. > > What's happening here is that the tests are launched using make test > TEST=test/hotspot/jtreg/:tier1_serviceability. One of those tests is the > (pre-existing unrelated to this PR) AgentWithVThreadTest. That test has a > `@compile AgentWithVThread.java AgentWithVThreadTest.java`. This triggers > compilation of those classes and also any referenced classes in those 2 > classes. One such class happens to be the test library's jdk.test.lib.Utils. > This is a test library class (used/referenced indirectly in that test). jtreg > ends up issuing a javac command with destination directory as the > AgentWithVThreadTest's test specific work directory: > > > -d > build/macosx-aarch64/test-support/jtreg_test_hotspot_jtreg_tier1_serviceability/classes/0/serviceability/jvmti/vthread/premain/AgentWithVThreadTest.d > > > So the `jdk.test.lib.Utils.class` (along with other classes) file ends up > being compiled to > `build/macosx-aarch64/test-support/jtreg_test_hotspot_jtreg_tier1_serviceability/classes/0/serviceability/jvmti/vthread/premain/AgentWithVThreadTest.d/jdk/test/lib/Utils.class`. > During this compilation, the `jdk.test.lib.util.JavaAgentBuilder` doesn't > get compiled because that class isn't referenced by AgentWithVThreadTest > (neither directly or indirectly). > > Then during the same test execution, jtreg notices a `@run` statement: > > > @run driver jdk.test.lib.util.JavaAgentBuilder .... > > > And to launch that run action, it first builds and compiles the > jdk.test.lib.util.JavaAgentBuilder and since this is a test library class, > jtreg ends up launching `javac` with a destination directory which is > common/shared by multiple tests: > > > -d > build/macosx-aarch64/test-support/jtreg_test_hotspot_jtreg_tier1_serviceability/classes/0/test/lib > > > Additionally, since this is being compiled in context of the > AgentWithVThreadTest, jtreg also passes the test specific work directory > (`build/macosx-aarch64/test-support/jtreg_test_hotspot_jtreg_tier1_serviceability/classes/0/serviceability/jvmti/vthread/premain/AgentWithVThreadTest.d`) > as the classpath to the javac command. So effectively, this compilation ends > up finding the `jdk.test.lib.Utils.class` in the test specific directory and > doesn't recompile to the shared location. Since the > `jdk.test.lib.util.JavaAgentBuilder` hasn't yet been compiled nor is located > in the test specific work directory, javac ends up compiling it and placing > it in the destinati... I was inspired by [CODETOOLS-7901986](https://bugs.openjdk.org/browse/CODETOOLS-7901986). By adding `@build jdk.test.lib.Utils` all tests are passed. The GitHub Actions jobs are finished successfully, too. I hope I could get a final review now. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/20373#discussion_r1708439201
