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Exceptions and Errors ignored due to unchecked Futures

See original GitHub issue

Describe the bug @keith-turner reported an issue where he had the wrong accumulo-core jar file deployed to a cluster and the TabletServer continued to run. When he changed the code to catch Throwable instead of catch Exception, this stacktrace was captured:

java.lang.NoSuchFieldError: TSERV_WAL_BUFFER
        at org.apache.accumulo.tserver.log.DfsLogger.open(DfsLogger.java:425) ~[accumulo-tserver-2.1.0-SNAPSHOT.jar:2.1.0-SNAPSHOT]
        at org.apache.accumulo.tserver.log.TabletServerLogger$2.run(TabletServerLogger.java:277) ~[accumulo-tserver-2.1.0-SNAPSHOT.jar:2.1.0-SNAPSHOT]
        at org.apache.accumulo.core.trace.TraceWrappedRunnable.run(TraceWrappedRunnable.java:52) ~[accumulo-core-2.1.0-SNAPSHOT.jar:2.1.0-SNAPSHOT]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) ~[?:?]
        at java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?]
        at org.apache.accumulo.core.trace.TraceWrappedRunnable.run(TraceWrappedRunnable.java:52) ~[accumulo-core-2.1.0-SNAPSHOT.jar:2.1.0-SNAPSHOT]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[?:?]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[?:?]
        at org.apache.accumulo.core.trace.TraceWrappedRunnable.run(TraceWrappedRunnable.java:52) ~[accumulo-core-2.1.0-SNAPSHOT.jar:2.1.0-SNAPSHOT]
        at java.lang.Thread.run(Thread.java:829) [?:?]

It turns out that the issue here is that ExecutorService.submit was being called and the Future result object was not being checked. When he changed the code to use ExecutorService.execute instead, then the AccumuloUncaughtExceptionHandler was invoked, the Error printed in the log, and the VM halted. When using submit, the TabletServer remained up, but in a Zombie non-functional state.

It appears that Futures are capturing Exceptions and Errors, so the UncaughtExceptionHandler is not being invoked. It would be nice if SpotBugs had a rule for this. The closest I found is https://github.com/spotbugs/spotbugs/issues/950, but it’s still open.

Issue Analytics

State:
Created 2 years ago
Comments:12 (12 by maintainers)

Top GitHub Comments

2reactions

dlmarioncommented, Feb 23, 2022

I added the following to the errorprone profile in the parent pom

                   -Xep:FutureReturnValueIgnored:ERROR \

It found 16 errors in the tserver module when I ran mvn -pl server/tserver -Perrorprone clean package -DskipTests

1reaction

jmark99commented, Feb 23, 2022

Removing the DisableAllWarnings is fine, but ErrorProne is fairly aggressive so there will be a lot of SuppressWarning annotations to add. Of course once all warnings are parsed you can always update the pom to ignore warnings we do not care about.

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