Fix: add threading lock around JVM startup to prevent parallel connect crash (issue #60)#92
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…t crash (issue #60) Multiple threads calling connect() simultaneously could both see isJVMStarted() return False and both attempt to start the JVM, causing a SIGSEGV crash. Add a threading.Lock to serialize JVM startup. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The original implementation held _jvm_startup_lock during the entire startJVM() call. If JPype internally spawns threads during JVM initialization that re-enter the module (e.g., via imports), the non-reentrant Lock would deadlock. Refactored to only hold the lock briefly when checking/setting a flag, then run startJVM() outside the lock. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Worker threads that call connect() get attached to the JVM via jpype.attachThreadToJVM(). Without explicit detachment, these threads leave zombie Java threads that prevent JVM shutdown, causing CI to time out. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
Fixes #60: JVM crash when multiple threads call
connect()simultaneously.Changes
threading.Lock(_jvm_startup_lock) to serialize JVM startup in_jdbc_connect_jpype()if not isJVMStarted(): startJVM()) was not atomic, allowing two threads to both attempt to start the JVM causing a SIGSEGVTest plan
ParallelConnectTest.test_parallel_connects_after_jvm_startedintest/test_mock.pyParallelConnectTest.test_jvm_startup_lock_existsintest/test_mock.pyParallelConnectTest.test_parallel_connects_with_hsqldbintest/test_integration.pyCloses #60
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