Refactor: do not keep around JRuby context reference

there's no need for this and makes code base inconsistent
... also the original intent seems no longer relevant :

was introduced at 57e7a8a56b
> allows for a massive simplification for the invocation of filters and
outputs from the Java execution

Fixes #11587

logstash-core/src/main/java/org/logstash/ConvertedMap.java

@@ -61,7 +61,7 @@ public final class ConvertedMap extends IdentityHashMap<String, Object> {
     }
 
     public static ConvertedMap newFromRubyHash(final RubyHash o) {
-        return newFromRubyHash(WorkerLoop.THREAD_CONTEXT.get(), o);
+        return newFromRubyHash(o.getRuntime().getCurrentContext(), o);
     }
 
     public static ConvertedMap newFromRubyHash(final ThreadContext context, final RubyHash o) {

logstash-core/src/main/java/org/logstash/config/ir/compiler/AbstractFilterDelegatorExt.java

@@ -11,7 +11,6 @@ import org.jruby.anno.JRubyMethod;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
 import org.logstash.RubyUtil;
-import org.logstash.execution.WorkerLoop;
 import org.logstash.ext.JrubyEventExtLibrary;
 import org.logstash.instrument.metrics.AbstractNamespacedMetricExt;
 import org.logstash.instrument.metrics.MetricKeys;
@@ -131,7 +130,7 @@ public abstract class AbstractFilterDelegatorExt extends RubyObject {
     @SuppressWarnings("rawtypes")
     public RubyArray flush(final IRubyObject input) {
         RubyHash options = (RubyHash) input;
-        final ThreadContext context = WorkerLoop.THREAD_CONTEXT.get();
+        final ThreadContext context = options.getRuntime().getCurrentContext();
         final IRubyObject newEvents = doFlush(context, options);
         final RubyArray result;
         if (newEvents.isNil()) {

logstash-core/src/main/java/org/logstash/config/ir/compiler/EventCondition.java

@@ -5,6 +5,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Predicate;
+
+import org.jruby.Ruby;
 import org.jruby.RubyString;
 import org.jruby.runtime.builtin.IRubyObject;
 import org.jruby.util.ByteList;
@@ -33,7 +35,6 @@ import org.logstash.config.ir.expression.binary.Or;
 import org.logstash.config.ir.expression.binary.RegexEq;
 import org.logstash.config.ir.expression.unary.Not;
 import org.logstash.config.ir.expression.unary.Truthy;
-import org.logstash.execution.WorkerLoop;
 import org.logstash.ext.JrubyEventExtLibrary;
 
 /**
@@ -481,7 +482,7 @@ public interface EventCondition {
             public boolean fulfilled(final JrubyEventExtLibrary.RubyEvent event) {
                 final Object tomatch = event.getEvent().getUnconvertedField(field);
                 return tomatch instanceof RubyString &&
-                    !((RubyString) tomatch).match(WorkerLoop.THREAD_CONTEXT.get(), regex).isNil();
+                    !((RubyString) tomatch).match(RubyUtil.RUBY.getCurrentContext(), regex).isNil();
             }
         }
 
@@ -490,10 +491,11 @@ public interface EventCondition {
             private final boolean matches;
 
             private ConstantMatches(final Object constant, final String regex) {
+                final Ruby runtime = RubyUtil.RUBY;
                 this.matches = constant instanceof String &&
-                        !(RubyUtil.RUBY.newString((String) constant).match(
+                        !(runtime.newString((String) constant).match(
-                                WorkerLoop.THREAD_CONTEXT.get(),
+                                runtime.getCurrentContext(),
-                                RubyUtil.RUBY.newString(regex)).isNil());
+                                runtime.newString(regex)).isNil());
             }
 
             @Override

logstash-core/src/main/java/org/logstash/config/ir/compiler/FilterDelegatorExt.java

@@ -12,7 +12,6 @@ import org.jruby.anno.JRubyMethod;
 import org.jruby.internal.runtime.methods.DynamicMethod;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
-import org.logstash.execution.WorkerLoop;
 import org.logstash.instrument.metrics.AbstractNamespacedMetricExt;
 import org.logstash.instrument.metrics.counter.LongCounter;
 
@@ -106,7 +105,7 @@ public final class FilterDelegatorExt extends AbstractFilterDelegatorExt {
         org.apache.logging.log4j.ThreadContext.put("plugin.id", pluginId.toString());
         try {
             return (RubyArray) filterMethod.call(
-                    WorkerLoop.THREAD_CONTEXT.get(), filter, filterClass, FILTER_METHOD_NAME, batch);
+                    getRuntime().getCurrentContext(), filter, filterClass, FILTER_METHOD_NAME, batch);
         } finally {
             org.apache.logging.log4j.ThreadContext.remove("plugin.id");
         }

logstash-core/src/main/java/org/logstash/config/ir/compiler/JavaFilterDelegatorExt.java

@@ -76,9 +76,10 @@ public class JavaFilterDelegatorExt extends AbstractFilterDelegatorExt {
     protected IRubyObject doFlush(final ThreadContext context, final RubyHash options) {
         if (filter.requiresFlush()) {
             Collection<Event> outputEvents = filter.flush(filterMatchListener);
-            @SuppressWarnings("rawtypes") RubyArray newBatch = RubyArray.newArray(RubyUtil.RUBY, outputEvents.size());
+            final Ruby runtime = context.runtime;
+            @SuppressWarnings("rawtypes") RubyArray newBatch = RubyArray.newArray(runtime, outputEvents.size());
             for (Event outputEvent : outputEvents) {
-                newBatch.add(JrubyEventExtLibrary.RubyEvent.newRubyEvent(RubyUtil.RUBY, (org.logstash.Event)outputEvent));
+                newBatch.add(JrubyEventExtLibrary.RubyEvent.newRubyEvent(runtime, (org.logstash.Event)outputEvent));
             }
             return newBatch;
         }

logstash-core/src/main/java/org/logstash/config/ir/compiler/OutputDelegatorExt.java

@@ -12,7 +12,6 @@ import org.jruby.runtime.Block;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
 import org.logstash.execution.ExecutionContextExt;
-import org.logstash.execution.WorkerLoop;
 import org.logstash.ext.JrubyEventExtLibrary;
 import org.logstash.instrument.metrics.AbstractMetricExt;
 
@@ -78,7 +77,7 @@ OutputDelegatorExt extends AbstractOutputDelegatorExt {
         try {
             final IRubyObject pluginId = this.getId();
             org.apache.logging.log4j.ThreadContext.put("plugin.id", pluginId.toString());
-            strategy.multiReceive(WorkerLoop.THREAD_CONTEXT.get(), (IRubyObject) batch);
+            strategy.multiReceive(getRuntime().getCurrentContext(), (IRubyObject) batch);
         } catch (final InterruptedException ex) {
             throw new IllegalStateException(ex);
         } finally {

logstash-core/src/main/java/org/logstash/execution/WorkerLoop.java

@@ -12,14 +12,6 @@ import org.logstash.config.ir.compiler.Dataset;
 
 public final class WorkerLoop implements Runnable {
 
-    /**
-     * Hard Reference to the Ruby {@link ThreadContext} for this thread. It is ok to keep
-     * a hard reference instead of Ruby's weak references here since we can expect worker threads
-     * to be runnable most of the time.
-     */
-    public static final ThreadLocal<ThreadContext> THREAD_CONTEXT =
-        ThreadLocal.withInitial(RubyUtil.RUBY::getCurrentContext);
-
     private static final Logger LOGGER = LogManager.getLogger(WorkerLoop.class);
 
     private final Dataset execution;

logstash-core/src/test/java/org/logstash/ext/JrubyMemoryReadClientExtTest.java

@@ -23,7 +23,7 @@ public final class JrubyMemoryReadClientExtTest {
             new ArrayBlockingQueue<>(10);
         final JrubyMemoryReadClientExt client =
             JrubyMemoryReadClientExt.create(queue, 5, 50);
-        final ThreadContext context = WorkerLoop.THREAD_CONTEXT.get();
+        final ThreadContext context = client.getRuntime().getCurrentContext();
         final QueueBatch batch = client.readBatch();
         final RubyHash inflight = client.rubyGetInflightBatches(context);
         assertThat(inflight.size(), is(1));