RFR: 8293067: (fs) Implement WatchService using system library (macOS)

[Alan Bateman]

On Thu, 8 Sep 2022 07:21:07 GMT, Maxim Kartashev <mkartashev at openjdk.org> wrote:

> In our CI system `test/jdk/java/nio/file/WatchService/Move.java` appears to time out consistently, although I have not seen it happen on my local machine.

I've been backed up with other things and finally getting to look at this more closely. For testing, I tried both release and debug builds across a range of macOS releases on both x64 and aarch64. Unfortunately there is a lot of timeouts and intermittent failures and across quite a range of macOS releases (from 10.15 to 12.2).

The most frequent failure seems to be the testOverflowEvent test in LotsOfEvents.  Here's an example failure:

----------System.out:(1/47)----------
Seed from RandomFactory = 1932318894124342221L
----------System.err:(12/655)----------
java.lang.RuntimeException: Key not signalled (unexpected)
	at LotsOfEvents.drainAndCheckOverflowEvents(LotsOfEvents.java:105)
	at LotsOfEvents.testOverflowEvent(LotsOfEvents.java:78)
	at LotsOfEvents.main(LotsOfEvents.java:51)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
	at java.base/java.lang.reflect.Method.invoke(Method.java:578)
	at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
	at java.base/java.lang.Thread.run(Thread.java:1591)

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PR: https://git.openjdk.org/jdk/pull/10140