Workaround for #14873

[jsvd]

import ffi from JRuby 9.3.9.0 to overcome jruby/jruby#7579

Since JRuby ignores the files in "lib/jni" and uses the ones inside "lib/jruby.jar", we have to inject the older versions into the new JRuby's jruby.jar

fixes #14873

[jsvd]

This fix isn't enough since JRuby ignores the files under "lib/jni" and uses the "jni" folder inside the jruby.jar. Two solutions are:

1. modify the jruby.jar to include the older files from JRuby 9.3.9.0
2. exploration: use -Djava.library.path= so JRuby looks at the path we want. it may require having to add logic to JvmOptionsParser.java to decide which directory to load from

[jsvd]

To test:

./gradlew clean assembleTarDistribution

$ cd build
$ cat Dockerfile 
FROM oraclelinux:7
RUN yum update -y
RUN yum install java-11-openjdk.aarch64 -y

COPY logstash-8.8.0-SNAPSHOT.tar.gz /root
WORKDIR /root
RUN tar -zxf logstash-8.8.0-SNAPSHOT.tar.gz
WORKDIR /root/logstash-8.8.0-SNAPSHOT

$ docker run -it mytest ./vendor/jruby/bin/jruby -Xnative.verbose -w -d --dev -e 'system "date"' 
Successfully loaded native POSIX impl.
Sat Feb 11 01:53:00 UTC 2023

[yaauie]

NIT: minor re-arrange, return to only getting the FFI libs that are known to have changed, and output information about what we are injecting. I'm ok with filing this as a follow-up.

Suggested change

	tasks.register("downloadAndInstallPreviousJRubyFFI", Copy) {
	dependsOn=[downloadPreviousJRuby]
	description "Install previous JRuby FFI files in the new JRuby directory"
	inputs.file(previousJrubyTarPath)
	outputs.dir("${projectDir}/vendor/jruby/lib/jni")
	outputs.file("${projectDir}/vendor/jruby/lib/jruby.jar")
	from tarTree(downloadPreviousJRuby.dest)
	eachFile { f ->
	f.path = f.path.replaceFirst("^jruby-${previousJRubyVersion}", '')
	}
	// Copy only the previous builds of libjffi that changed from JRuby 9.3.9.0 to 9.3.10.0
	include "**/lib/jni/**/*"
	includeEmptyDirs = false
	into "${projectDir}/vendor/jruby/tmp"
	doLast {
	ant.jar(destfile: "${projectDir}/vendor/jruby/lib/jruby.jar", update: true) {
	fileset(dir: "${projectDir}/vendor/jruby/tmp/lib")
	}
	delete files("${projectDir}/vendor/jruby/tmp")
	}
	}
	tasks.register("downloadAndInstallPreviousJRubyFFI", Copy) {
	dependsOn=[downloadPreviousJRuby]
	description "Install previous JRuby FFI files in the new JRuby directory"
	inputs.file(previousJrubyTarPath)
	outputs.dir("${projectDir}/vendor/jruby/lib/jni")
	outputs.file("${projectDir}/vendor/jruby/lib/jruby.jar")
	includeEmptyDirs = false
	from(tarTree(downloadPreviousJRuby.dest)) {
	// Copy only the previous builds of libjffi that changed from JRuby 9.3.9.0 to 9.3.10.0
	include "**/lib/jni/aarch64-Linux/libjffi-1.2.so"
	include "**/lib/jni/arm-Linux/libjffi-1.2.so"
	include "**/lib/jni/i386-Linux/libjffi-1.2.so"
	include "**/lib/jni/x86_64-Linux/libjffi-1.2.so"
	eachFile { f ->
	f.path = f.path.replaceFirst("^jruby-${previousJRubyVersion}", '')
	println "Installing Previous FFI: ${f.path}"
	}
	}
	into "${projectDir}/vendor/jruby/tmp"
	doLast {
	ant.jar(destfile: "${projectDir}/vendor/jruby/lib/jruby.jar", update: true) {
	fileset(dir: "${projectDir}/vendor/jruby/tmp/lib")
	}
	delete files("${projectDir}/vendor/jruby/tmp")
	}
	}

[yaauie]

LGTM, and dipping down to ant is much more straight-forward than the zip utility method I was attempting.

[jsvd]

@logstashmachine backport 8.7

[jsvd]

@logstashmachine backport 8.6