[
https://issues.apache.org/jira/browse/GROOVY-9381?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18061924#comment-18061924
]
ASF GitHub Bot commented on GROOVY-9381:
----------------------------------------
Copilot commented on code in PR #2386:
URL: https://github.com/apache/groovy/pull/2386#discussion_r2868613864
##########
src/main/java/org/apache/groovy/runtime/async/AsyncStreamGenerator.java:
##########
@@ -0,0 +1,123 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.groovy.runtime.async;
+
+import groovy.concurrent.AsyncStream;
+import groovy.concurrent.Awaitable;
+
+import java.util.concurrent.SynchronousQueue;
+
+/**
+ * A producer/consumer implementation of {@link AsyncStream} used by
+ * {@code async} methods that contain {@code yield return} statements.
+ * <p>
+ * The producer (method body) runs on a separate thread and calls
+ * {@link #yield(Object)} for each emitted element. The consumer
+ * calls {@link #moveNext()}/{@link #getCurrent()} — typically via
+ * a {@code for await} loop.
+ * <p>
+ * Uses a {@link SynchronousQueue} to provide natural back-pressure:
+ * the producer thread blocks at each {@code yield return} until the
+ * consumer has consumed the previous element (mirroring C#'s async
+ * iterator suspension semantics).
+ * <p>
+ * This class is an internal implementation detail and should not be referenced
+ * directly by user code.
+ *
+ * @param <T> the element type
+ * @since 6.0.0
+ */
+public class AsyncStreamGenerator<T> implements AsyncStream<T> {
+
+ private static final Object DONE = new Object();
+
+ private final SynchronousQueue<Object> queue = new SynchronousQueue<>();
+ private T current;
+
+ /**
+ * Produces the next element. Called from the generator body when
+ * a {@code yield return expr} statement is executed. Blocks until
+ * the consumer is ready.
+ */
+ public void yield(Object value) {
+ try {
+ queue.put(new Item(value));
+ } catch (InterruptedException e) {
+ Thread.currentThread().interrupt();
+ throw new java.util.concurrent.CancellationException("Interrupted
during yield");
+ }
Review Comment:
`SynchronousQueue.put(...)` in `yield()` blocks until a consumer calls
`moveNext()`. If a consumer abandons iteration early (e.g., breaks out of a
`for await` loop), the producer thread can block forever in
`yield()`/`complete()`, leaking an executor thread. Consider adding a
cancellation/close mechanism and ensuring compiler-generated `for await` loops
signal early termination.
##########
src/test/groovy/org/codehaus/groovy/transform/AsyncVirtualThreadTest.groovy:
##########
@@ -0,0 +1,1138 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.codehaus.groovy.transform
+
+import org.junit.jupiter.api.Test
+
+import static groovy.test.GroovyAssert.assertScript
+
+/**
+ * Tests for virtual thread integration, executor configuration, exception
+ * handling consistency across async methods/closures/lambdas, and coverage
+ * improvements for the async/await feature.
+ *
+ * @since 6.0.0
+ */
+final class AsyncVirtualThreadTest {
+
+ // --
> Support async/await like ES7
> ----------------------------
>
> Key: GROOVY-9381
> URL: https://issues.apache.org/jira/browse/GROOVY-9381
> Project: Groovy
> Issue Type: New Feature
> Reporter: Daniel Sun
> Priority: Major
>
> Here is an example to show proposed syntax and backend API(Java's
> {{CompletableFuture}} or GPars's {{{}Promise{}}}), but I think it's better
> for Groovy to have its own {{Promise}} to decouple with Java API because
> async/await as a language feature should be as stable as possible.
> {{async}} will generate the {{Awaitable}} instance such as Groovy {{Promise}}
> implementing the {{Awaitable}} interface, and {{await}} can wait for any
> {{Awaitable}} instance to complete and unwrap it for the result.
> {code:java}
> /**
> * 1. An async function that simulates a network API call.
> * The 'async' keyword implies it runs asynchronously without blocking.
> */
> async fetchUserData(userId) {
> println "Starting to fetch data for user ${userId}..."
>
> // Simulate a 1-second network delay.
> Thread.sleep(1000)
>
> println "Fetch successful!"
> // The 'async' function implicitly returns a "CompletableFuture" or
> "Promise" containing this value.
> return [userId: userId, name: 'Daniel']
> }
> /**
> * 2. An async function that uses 'await' to consume the result.
> */
> async processUserData() {
> println "Process started, preparing to fetch user data..."
>
> try {
> // 'await' pauses this function until fetchUserData completes
> // and returns the final result directly.
> def user = await fetchUserData(1)
>
> println "Data received: ${user}"
> return "Processing complete for ${user.name}."
>
> } catch (Exception e) {
> return "An error occurred: ${e.message}"
> }
> }
> // --- Execution ---
> println "Script starting..."
> // Kick off the entire asynchronous process.
> def future = processUserData()
> // This line executes immediately, proving the process is non-blocking.
> println "Script continues to run while user data is being fetched in the
> background..."
> def result = future.get()
> println "Script finished: ${result}"
> {code}
> Use async/await with closure or lambda expression:
> {code}
> // use closure
> def c = async {
> println "Process started, preparing to fetch user data..."
>
> try {
> // 'await' pauses this function until fetchUserData completes
> // and returns the final result directly.
> def user = await fetchUserData(1)
>
> println "Data received: ${user}"
> return "Processing complete for ${user.name}."
>
> } catch (Exception e) {
> return "An error occurred: ${e.message}"
> }
> }
> def future = c()
> {code}
> {code}
> // use lambda expression
> def c = async () -> {
> println "Process started, preparing to fetch user data..."
>
> try {
> // 'await' pauses this function until fetchUserData completes
> // and returns the final result directly.
> def user = await fetchUserData(1)
>
> println "Data received: ${user}"
> return "Processing complete for ${user.name}."
>
> } catch (Exception e) {
> return "An error occurred: ${e.message}"
> }
> }
> def future = c()
> {code}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
