`ActiveSessionException` in TestNG integration suggests conflict with parallel execution

A user running TestNG tests with the appmap-java agent is encountering an ActiveSessionException, which causes the recording to fail. We suspect this is due to TestNG's parallel execution feature, which the AppMap agent's Recorder may not currently support.

When multiple tests run concurrently, each test thread appears to trigger the AppMap TestNG hook (com.appland.appmap.process.hooks.test.TestNG.testng) and attempts to call startRecording. The first test succeeds, but subsequent concurrent tests fail when the Recorder detects that a session is already active, throwing the exception.

Error Log & Stack Trace

The key error message from the user's log is:

AppMap agent version 1.28.0 starting
[TestNG] Running:
  <path-to-project>\src\test\resources\testsuite\testing.xml
...
17:08:07.398 [main] WARN RecordingSupport.startRecording: com.appland.appmap.record.ActiveSessionException: an active recording session already exists
    at com.appland.appmap.record.Recorder$ActiveSession.set(Recorder.java:162)
    at com.appland.appmap.record.Recorder.start(Recorder.java:241)
    at com.appland.appmap.process.hooks.RecordingSupport.startRecording(RecordingSupport.java:59)
    at com.appland.appmap.process.hooks.test.TestSupport.startRecording(TestSupport.java:63)
    at com.appland.appmap.process.hooks.test.TestSupport.startRecording(TestSupport.java:25)
    at com.appland.appmap.process.hooks.test.TestNG.testng(TestNG.java:45)

Requested Action

1. Investigate: Please confirm if appmap-java's TestNG support is compatible with parallel test execution (e.g., parallel="methods" or parallel="tests" in the testng.xml suite).
2. Remediate:
   • Ideally: If possible, update the agent to properly support parallel TestNG execution, perhaps by managing recording sessions on a per-thread basis.
   • Alternatively: If parallel support is not feasible or as an interim solution, please add logic to detect when TestNG parallelism is enabled and automatically disable it (force serial execution) when the AppMap agent is attached. This would prevent the crash and allow users to generate AppMaps, albeit with a slower test run.

Full Terminal Output (for context)

"<path-to-java>\bin\java.exe" -ea -Didea.test.cyclic.buffer.size=1048576 -Dappmap.config.file=<path-to-project>\appmap.yml -javaagent:<user-home>\.appmap\lib\java\appmap.jar "-javaagent:<path-to-ide>\lib\idea_rt.jar=56911" -javaagent:<user-home>\AppData\Local\JetBrains\IdeaIC\captureAgent\debugger-agent.jar -Dkotlinx.coroutines.debug.enable.creation.stack.trace=false -Ddebugger.agent.enable.coroutines=true
 -Dkotlinx.coroutines.debug.enable.flows.stack.trace=true -Dkotlinx.coroutines.debug.enable.mutable.state.flows.stack.trace=true -Dfile.encoding=UTF-8 @<temp-path>\idea_arg_file1573352798 com.intellij.rt.testng.RemoteTestNGStarter -usedefaultlisteners
 false -socket56910 @w@<temp-path>\idea_working_dirs_testng2.tmp -temp <temp-path>\idea_testng2.tmp

AppMap agent version 1.28.0 starting

[TestNG] Running:

  <path-to-project>\src\test\resources\testsuite\testing.xml
Java HotSpot(TM) 64-Bit Server VM warning: Sharing 
is only supported for boot loader classes because bootstrap classpath 
has been appended

SLF4J(W): No SLF4J providers were found.
.. 
17:08:07.398 [main] WARN RecordingSupport.startRecording: com.appland.appmap.record.ActiveSessionException: an active recording session already exists

    at com.appland.appmap.record.Recorder$ActiveSession.set(Recorder.java:162)

    at com.appland.appmap.record.Recorder.start(Recorder.java:241)

    at com.appland.appmap.process.hooks.RecordingSupport.startRecording(RecordingSupport.java:59)

    at com.appland.appmap.process.hooks.test.TestSupport.startRecording(TestSupport.java:63)

    at com.appland.appmap.process.hooks.test.TestSupport.startRecording(TestSupport.java:25)

    at com.appland.appmap.process.hooks.test.TestNG.testng(TestNG.java:45)

Start with com.appland.appmap.process.hooks.test.TestNG.testng and the Recorder.start path shown in the stack trace, then inspect RecordingSupport.startRecording and TestSupport.startRecording. Reproduce the failure with TestNG parallel="methods" or parallel="tests" and determine whether sessions can be isolated per thread or parallelism must be disabled. Done means parallel execution no longer causes ActiveSessionException and recordings still complete.