Add SimulatorThread support for Thread subclasses under simulation#29
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ylecaillez merged 1 commit intopingidentity:mainfrom Apr 11, 2026
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… simulation Rewrite Thread subclasses to extend SimulatorThread (a VirtualThread injected into java.base via --patch-module) so they run under the deterministic scheduler. This is experimental and may be reverted if it causes more issues than it solves. The approach of patching java.base and rewriting superclass hierarchies is inherently fragile and may break with JDK updates or unusual Thread subclass patterns. Build time: - PatchModuleGenerator strips ACC_FINAL from VirtualThread and compiles SimulatorThread from source, packaging both into opendst-patch.jar - Instrumentation rewrites 'extends Thread' to 'extends SimulatorThread' and redirects super() calls in constructors Runtime: - --patch-module java.base=opendst-patch.jar injects SimulatorThread - installSimulatorThreadCallback() wires the per-node executor and thread attachment callbacks into SimulatorThread's static fields Also removes CDS support as it is incompatible with --patch-module.
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Solve the 'extends Thread' problem: classes that subclass Thread now run as virtual threads under deterministic simulation.
Build-time:
Runtime:
Also removes CDS support: --patch-module on java.base makes CDS impossible (JVM refuses it), so the --cds/--no-cds flag was dead code.