Reset installer Thread's state. Closes #121 (#124)

agent/src/main/java/reactor/blockhound/BlockHound.java

@@ -409,6 +409,9 @@ public void install() {
             BlockHoundRuntime.threadPredicate = threadPredicate;
 
             onBlockingMethod = originalOnBlockingMethod;
+
+            // Re-evaluate the current thread's state after assigning user-provided predicates
+            BlockHoundRuntime.STATE.remove();
         }
 
         private void testInstrumentation() {

example/src/test/java/com/example/DynamicCurrentThreadTest.java

@@ -0,0 +1,41 @@
+package com.example;
+
+import org.assertj.core.api.Assertions;
+import org.junit.After;
+import org.junit.Test;
+import reactor.blockhound.BlockHound;
+import reactor.blockhound.BlockingOperationError;
+
+public class DynamicCurrentThreadTest {
+
+    private static final ThreadLocal<Boolean> CAN_BLOCK = ThreadLocal.withInitial(() -> true);
+
+    static {
+        var testThread = Thread.currentThread();
+        BlockHound.install(b -> {
+            b.addDynamicThreadPredicate(testThread::equals);
+
+            b.nonBlockingThreadPredicate(p -> p.or(thread -> {
+                return !CAN_BLOCK.get();
+            }));
+        });
+    }
+
+    @After
+    public void tearDown() {
+        CAN_BLOCK.remove();
+    }
+
+    @Test
+    public void testChangingCurrentThreadsStatus() throws Exception {
+        Thread.sleep(0);
+
+        CAN_BLOCK.set(false);
+        Assertions.assertThatThrownBy(() -> Thread.sleep(0))
+                  .isInstanceOf(BlockingOperationError.class);
+
+        // Reset to default
+        CAN_BLOCK.remove();
+        Thread.sleep(0);
+    }
+}