[ji] avoid already initialized constant warnings#8250
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kares merged 4 commits intojruby:masterfrom Jun 5, 2024
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similar to how `java_import` works we should check whether the constant was already set and not set it again - this effectively avoids emitting a lot of "already initialized constant" in a multi threaded environment
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| sleep 0.01; mod::Field | ||
| sleep 0.01; mod::ThreadInfo | ||
| sleep 0.01; mod::LockInfo | ||
| sleep 0.01; mod::Array |
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A better concurrency test could be to have each spawned thread wait on something like a CountDownLatch before trying to access each imported Java class, and have the main thread release the latches one at a time.
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yeah, that's a good point. although this actually does reproduce both types of warnings fairly reliably...
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| output = with_stderr_captured do | ||
| threads = (0..100).map do | ||
| latch = java.util.concurrent.CountDownLatch.new(1) | ||
| waiting_thread_count = java.util.concurrent.atomic.AtomicInteger.new |
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What about making this one a CountDownLatch too? Waiting for something to happen N times is what they're designed for, even if I do often end up using them with N = 1 😄
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similar to how
java_importworks we should check whether the constant was already set and not set it again - this effectively avoids emitting a lot of "already initialized constant" in a multi threaded environment.on top of that using synchronization we avoid "already initialized constant" even in rare cases (which could have still happened with Java proxy class initialization in general).
reproducer for the warnings is easy to spot esp. with
include_package:jruby -v -e "mod = Module.new { include_package 'java.lang.reflect' }; threads = (0..10).map { Thread.start { sleep(0.01); mod::Array } }.each { |t| t.join }"