Fix Continuation Leakage

Fix continuation leakage

Instrumentation tests run the diagnostic automatically. A failure includes the capture, resume, resolution, scope, thread, timing, and callsite data needed to find the missing lifecycle edge.

Work the failure

1. Resolve the actual Gradle module path and failing suite from CI or the module's tasks. Nesting varies (for example, netty:netty-4.1 versus kotlin-coroutines-1.3). Use forkedTest for *ForkedTest* classes, or the suite-specific forked task such as latestDepForkedTest. Run the smallest failing test with full output:

set -o pipefail
./gradlew :dd-java-agent:instrumentation:<module-path>:<test-task> --tests '<FQCN-or-pattern>' --info 2>&1 | tee /tmp/scopediag-run.txt

2. Verify the selected test ran in that task's XML results; a successful build with no discovered tests is not validation. Find Scope/continuation timeline in the output. If Gradle hides it, inspect the test XML's <system-out> under the module's build/test-results directory.
3. Follow the failing record from its first event:
   • LEAKED / NEVER_CLOSED: find the success, error, cancellation, and rejection exits that skipped release() or close().
   • DOUBLE_FINISH: find two owners of the same cleanup.
   • ACTIVATE_AFTER_RESOLVE: find work scheduled after ownership ended.
   • LATE_FINISH / CLOSE_WRONG_THREAD: advisory evidence; verify whether ordering is valid.
   • [deferred-cleanup]: a root iteration scope transferred cleanup to the bounded iteration cleaner. It may remain open at the test boundary and is not a leak. Do not generalize this to other ITERATION scopes; an unregistered iteration scope must still close normally.
4. Classify the captured work before changing code:
   • For a real asynchronous operation, repair success, failure, cancellation, and rejection cleanup.
   • If the test started the work, wait for its terminal event and dispose or close it before the test ends.
   • If a framework initializer creates a permanent sentinel with no context consumer, disable propagation only around that creation boundary. Match the exact type and method, and update knownMatchingTypes() when shortcut matching is used. Check static initialization (<clinit>): first use under an active request can capture its context in singleton tasks, including shaded Netty GlobalEventExecutor sentinels. Reproduce first use in a fresh JVM; prewarming can hide the bug. Do not suppress all class initializers.
   • If an executor replaces a task before delegating, avoid capturing the discarded task while preserving capture for the task actually submitted.
   • For intentionally delayed work, wait for its documented terminal event rather than suppressing propagation.
   • For a context swap, verify both restoration and resource cleanup. Restore or close the returned ownership object in finally; do not ignore every swap.
5. Prefer a test-lifecycle fix when production behavior is correct. Otherwise fix ownership where it breaks, with one owner and try/finally cleanup across every exit.
6. Rerun the failing test, then its module. Validate the leaked record and root-trace publication separately from trace-count or arrival-order assertions; fixing a leak may expose an unrelated flaky assertion.

Fixture failures

Automatic recording covers Spock setupSpec() / cleanupSpec() and JUnit @BeforeAll / @AfterAll, in addition to per-test setup and cleanup. The failure output identifies whether the problem belongs to suite setup, one test, or suite cleanup. Code that runs before the instrumentation-test harness initializes the tracer remains outside this window.

Apply process-wide configuration before starting servers, actor systems, executors, or other long-lived fixtures. Use a forked test or recreate the fixture when its static state cannot be reset safely.