Eliminate native access and memory warnings#174
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headius merged 2 commits intojnr:masterfrom Oct 24, 2025
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This avoids warnings when using Unsafe methods to do native memory access. These operations will instead use JNI to access native memory, and eventually Java's FFM APIs for better performance. Fixes jnr#165 by avoiding Unsafe when on JDK 23 or higher. See jruby/jruby#8696 for some prior discussion about these warnings.
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Additional information about enabling native access... There is a module method here that can do it, but only if the caller has native access already enabled: https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/lang/ModuleLayer.Controller.html#enableNativeAccess(java.lang.Module) There's a manifest entry that can be used to enable native access to all unnamed modules (all classpath code) but it is only honored from the main jar (e.g. JRuby's main jar could include this for running directly). |
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This PR will address warnings produced when we attempt to access native memory using Unsafe or load native libraries.
The Unsafe accesses should eventually be replaced by Panama FFM calls, but for now we just avoid using Unsafe at all when we are running on JDK 23 or higher (the level at which they started to warn more noisily).
The native library load obviously can't be eliminated, but we will modify the jar file to request native access when run as an unnamed module, and when run as a module (either as part of a jar as in JRuby or as a standalone module) the specified command-line flag will probably remain necessary.