Add non-blocking flock() and zend_async_task_new() factory

flock() now offloads to libuv thread pool inside coroutines,
preventing event loop blocking. Added libuv_new_task() factory
registered through reactor API, replacing manual task initialization.

Author: EdmondDantes

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to the Async extension for PHP will be documented in this fi
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.6.2] - 2026-03-24
+
+### Added
+- **Non-blocking `flock()`**: `flock()` no longer blocks the event loop. The lock operation is offloaded to the libuv thread pool via `zend_async_task_t`, allowing other coroutines to continue executing while waiting for a file lock.
+- **`zend_async_task_new()` API**: New factory function for creating thread pool tasks, registered through the reactor like timer and IO events. Replaces manual `pecalloc` + field initialization.
+
 ## [0.6.1] - 2026-03-15
 
 ### Fixed

libuv_reactor.c

@@ -1955,6 +1955,35 @@ static bool libuv_task_dispose(zend_async_event_t *event)
 
 /* }}} */
 
+/* {{{ libuv_new_task */
+static zend_async_task_t *libuv_new_task(zend_async_task_run_t run, void *data, size_t extra_size)
+{
+	if (UNEXPECTED(run == NULL)) {
+		async_throw_error("Cannot create a task without a run function");
+		return NULL;
+	}
+
+	const size_t total_size = sizeof(zend_async_task_t) + extra_size;
+	zend_async_task_t *task = pecalloc(1, total_size, 0);
+
+	zend_async_event_t *event = &task->base;
+	event->ref_count = 1;
+	event->extra_offset = extra_size > 0 ? sizeof(zend_async_task_t) : 0;
+	event->add_callback = libuv_add_callback;
+	event->del_callback = libuv_remove_callback;
+	event->start = libuv_task_start;
+	event->stop = libuv_task_stop;
+	event->dispose = libuv_task_dispose;
+	event->info = libuv_task_info;
+
+	task->run = run;
+	task->data = data;
+
+	return task;
+}
+
+/* }}} */
+
 /* {{{ libuv_queue_task */
 static bool libuv_queue_task(zend_async_task_t *task)
 {
@@ -1975,16 +2004,6 @@ static bool libuv_queue_task(zend_async_task_t *task)
 		}
 	}
 
-	/* Initialize the event methods on the task */
-	zend_async_event_t *event = &task->base;
-	event->ref_count = 1;
-	event->add_callback = libuv_add_callback;
-	event->del_callback = libuv_remove_callback;
-	event->start = libuv_task_start;
-	event->stop = libuv_task_stop;
-	event->dispose = libuv_task_dispose;
-	event->info = libuv_task_info;
-
 	/* Allocate the libuv work wrapper */
 	libuv_work_wrapper_t *wrapper = pecalloc(1, sizeof(libuv_work_wrapper_t), 0);
 	wrapper->task = task;
@@ -4530,5 +4549,5 @@ void async_libuv_reactor_register(void)
 						   libuv_io_set_option,
 						   libuv_udp_set_membership);
 
-	zend_async_thread_pool_register(LIBUV_REACTOR_NAME, false, libuv_queue_task);
+	zend_async_thread_pool_register(LIBUV_REACTOR_NAME, false, libuv_new_task, libuv_queue_task);
 }

tests/io/081-flock_non_blocking_event_loop.phpt

@@ -0,0 +1,52 @@
+--TEST--
+flock() does not block the event loop in coroutines
+--FILE--
+<?php
+
+use function Async\spawn;
+use function Async\await;
+
+echo "Start\n";
+
+$tmpfile = tempnam(sys_get_temp_dir(), 'async_flock_test_');
+file_put_contents($tmpfile, "test");
+
+// Take the lock in the main context before spawning coroutines
+$main_fp = fopen($tmpfile, 'r');
+flock($main_fp, LOCK_EX);
+echo "main: locked\n";
+
+$locker = spawn(function() use ($tmpfile) {
+    echo "locker: waiting for lock\n";
+    $fp = fopen($tmpfile, 'r');
+    flock($fp, LOCK_EX);
+    echo "locker: acquired\n";
+    flock($fp, LOCK_UN);
+    fclose($fp);
+});
+
+$worker = spawn(function() {
+    echo "worker: running\n";
+});
+
+// Let coroutines run — worker should complete, locker should be blocked in thread pool
+Async\delay(50);
+
+echo "main: unlocking\n";
+flock($main_fp, LOCK_UN);
+fclose($main_fp);
+
+await($locker);
+
+unlink($tmpfile);
+echo "End\n";
+
+?>
+--EXPECT--
+Start
+main: locked
+locker: waiting for lock
+worker: running
+main: unlocking
+locker: acquired
+End