Fix missing volatile on ShreddedPaperConfiguration.instance#76
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ShreddedPaperConfiguration.get() is read from every region-tick-pool thread, but set() is called from whatever thread runs /reload (not a region-tick thread). Without volatile there is no happens-before edge between a reload and later reads on other threads, so per the JMM a tick thread is free to keep observing the pre-reload config object indefinitely after /reload flips a setting.
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Summary
Found while investigating #49 (unrelated, reporting separately since it's a distinct bug).
ShreddedPaperConfiguration.instanceis a plainstaticfield.get()is read constantly from every region-tick-pool thread;set()is called from whatever thread runs/reload(not a region-tick thread). Withoutvolatilethere's no happens-before edge between a write and later reads on other threads, so per the JMM a tick thread is free to keep observing the pre-reload config object indefinitely, including after an operator flips amultithreading/optimizationssetting via/reload confirm.Test plan
./gradlew :shreddedpaper-server:compileJava)