Merge pull request #71 from true-async/fiber-support

Fiber support

Author: EdmondDantes

CHANGELOG.md

@@ -5,10 +5,23 @@ 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).
 
-## [0.5.0] - 2025-10-31
+## [0.5.0] - 2025-12-31
 
 ### Added
+- **Fiber Support**: Full integration of PHP Fibers with TrueAsync coroutine system
+  - `Fiber::suspend()` and `Fiber::resume()` work in async scheduler context
+  - `Fiber::getCoroutine()` method to access fiber's coroutine
+  - Fiber status methods (isStarted, isSuspended, isRunning, isTerminated)
+  - Support for nested fibers and fiber-coroutine interactions
+  - Comprehensive test coverage for all fiber scenarios
 - **TrueAsync API**: Added `ZEND_ASYNC_SCHEDULER_LAUNCH()` macro for scheduler initialization
+- **TrueAsync API**: Updated to version 0.8.0 with fiber support
+
+### Fixed
+- **Critical GC Bug**: Fixed garbage collection crash during coroutine cancellation when exception occurs in main coroutine while GC is running
+- Fixed double free in `zend_fiber_object_destroy()`
+- Fixed `stream_select()` for `timeout == NULL` case in async context
+- Fixed fiber memory leaks and improved GC logic
 
 ### Changed
 - **Deadlock Detection**: Replaced warnings with structured exception handling

coroutine.c

@@ -343,7 +343,10 @@ zend_coroutine_t *async_new_coroutine(zend_async_scope_t *scope)
 {
 	zend_object *object = coroutine_object_create(async_ce_coroutine);
 
-	if (UNEXPECTED(EG(exception))) {
+	if (UNEXPECTED(object == NULL || EG(exception))) {
+		if (object != NULL) {
+			zend_object_release(object);
+		}
 		return NULL;
 	}
 

coroutine.h

@@ -17,6 +17,7 @@
 #define COROUTINE_H
 
 #include "php_async_api.h"
+#include <Zend/zend_fibers.h>
 #include <Zend/zend_async_API.h>
 
 /* Fiber context structure for pooling */

libuv_reactor.c

@@ -168,12 +168,12 @@ bool libuv_reactor_execute(bool no_wait)
 {
 	// OPTIMIZATION: Skip uv_run() if no libuv handles to avoid unnecessary clock_gettime() calls
 	if (!uv_loop_alive(UVLOOP)) {
-		return ZEND_ASYNC_ACTIVE_EVENT_COUNT > 0;
+		return false;
 	}
 
 	const bool has_handles = uv_run(UVLOOP, no_wait ? UV_RUN_NOWAIT : UV_RUN_ONCE);
 
-	return ZEND_ASYNC_ACTIVE_EVENT_COUNT > 0 || has_handles;
+	return has_handles && ZEND_ASYNC_ACTIVE_EVENT_COUNT > 0;
 }
 
 /* }}} */

scheduler.c

@@ -526,6 +526,47 @@ static bool resolve_deadlocks(void)
 		return false;
 	}
 
+	//
+	// Let’s count the number of coroutine-fibers that are in the YIELD state.
+	// This state differs from the regular Suspended state in that
+	// the Fiber has transferred control back to the parent coroutine.
+	//
+	zend_long fiber_coroutines_count = 0;
+
+	ZEND_HASH_FOREACH_VAL(&ASYNC_G(coroutines), value) {
+		const zend_coroutine_t *coroutine = (zend_coroutine_t *) Z_PTR_P(value);
+
+		if (ZEND_COROUTINE_IS_FIBER(coroutine)
+			&& ZEND_COROUTINE_IS_YIELD(coroutine)
+			&& coroutine->extended_data != NULL) {
+			fiber_coroutines_count++;
+		}
+	}
+	ZEND_HASH_FOREACH_END();
+
+	//
+	// If all coroutines are fiber coroutines in the SUSPENDED state,
+	// we can simply cancel them without creating a deadlock exception.
+	//
+	if (fiber_coroutines_count == real_coroutines) {
+
+		ZEND_HASH_FOREACH_VAL(&ASYNC_G(coroutines), value) {
+			zend_coroutine_t *coroutine = (zend_coroutine_t *) Z_PTR_P(value);
+
+			if (ZEND_COROUTINE_IS_FIBER(coroutine)
+				&& ZEND_COROUTINE_IS_YIELD(coroutine)
+				&& coroutine->extended_data != NULL) {
+					ZEND_ASYNC_CANCEL(coroutine, zend_create_graceful_exit(), true);
+
+				if (UNEXPECTED(EG(exception) != NULL)) {
+					return true;
+				}
+			}
+		}
+		ZEND_HASH_FOREACH_END();
+		return false;
+	}
+
 	// Create deadlock exception to be set as exit_exception
 	zend_object *deadlock_exception = async_new_exception(async_ce_deadlock_error, 
 		"Deadlock detected: no active coroutines, %u coroutines in waiting", real_coroutines);
@@ -552,7 +593,7 @@ static bool resolve_deadlocks(void)
 		ZEND_ASYNC_CANCEL(
 				&coroutine->coroutine, async_new_exception(async_ce_cancellation_exception, "Deadlock detected"), true);
 
-		if (EG(exception) != NULL) {
+		if (UNEXPECTED(EG(exception) != NULL)) {
 			return true;
 		}
 	}
@@ -1025,6 +1066,16 @@ bool async_scheduler_coroutine_enqueue(zend_coroutine_t *coroutine)
 				// save the filename and line number where the coroutine was created
 				zend_apply_current_filename_and_line(&coroutine->filename, &coroutine->lineno);
 
+				// Notify scope that a new coroutine has been enqueued
+				zend_async_scope_t *scope = coroutine->scope;
+
+				if (UNEXPECTED(scope == NULL)) {
+					// throw error if the coroutine has no scope
+					coroutine->waker->status = ZEND_ASYNC_WAKER_NO_STATUS;
+					async_throw_error("The coroutine has no scope assigned");
+					return false;
+				}
+
 				if (UNEXPECTED(zend_hash_index_add_ptr(&ASYNC_G(coroutines), ((async_coroutine_t *)coroutine)->std.handle, coroutine) == NULL)) {
 					coroutine->waker->status = ZEND_ASYNC_WAKER_IGNORED;
 					async_throw_error("Failed to add coroutine to the list");
@@ -1033,8 +1084,6 @@ bool async_scheduler_coroutine_enqueue(zend_coroutine_t *coroutine)
 
 				ZEND_ASYNC_INCREASE_COROUTINE_COUNT;
 
-				// Notify scope that a new coroutine has been enqueued
-				zend_async_scope_t *scope = coroutine->scope;
 				scope->after_coroutine_enqueue(coroutine, scope);
 				if (UNEXPECTED(EG(exception))) {
 					coroutine->waker->status = ZEND_ASYNC_WAKER_IGNORED;

tests/edge_cases/007-fiber_first_then_spawn.phpt

@@ -46,5 +46,11 @@ echo "Test completed\n";
 Test: Fiber first, then spawn
 Starting Fiber
 Inside Fiber
-Async exception caught: Cannot spawn a coroutine when async is disabled
+Fiber attempting to continue after spawn
+Inside spawned coroutine from Fiber
+Fiber suspended with: fiber suspended
+Resuming Fiber
+Coroutine completed
+Fiber resumed
+Fiber returned: fiber done
 Test completed

tests/edge_cases/008-spawn_first_then_fiber.phpt

@@ -55,7 +55,14 @@ echo "Test completed\n";
 --EXPECTF--
 Test: Spawn first, then Fiber
 Coroutine spawned, now creating Fiber
-Error caught: Cannot create a fiber while an True Async is active
-Test completed
+Starting Fiber
 Coroutine started
-Coroutine resumed
+Inside Fiber - this should conflict with active scheduler
+Coroutine resumed
+Fiber suspended with: fiber suspended
+Resuming Fiber
+Fiber resumed
+Fiber completed with: fiber done
+Getting coroutine result
+Coroutine completed with: coroutine result
+Test completed

tests/edge_cases/009-fiber_spawn_destructor.phpt

@@ -100,14 +100,18 @@ Created: SpawnInDestructor
 Starting some async operations
 Unsetting objects to trigger destructors
 Destructing: FiberInDestructor
-Error in destructor: Cannot create a fiber while an True Async is active
+Starting fiber in destructor
+Main coroutine running
+Fiber running in destructor
+Main coroutine resumed
+Fiber suspended with: destructor fiber
+Fiber resumed in destructor
+Fiber completed with: destructor done
 Destructor finished: FiberInDestructor
 Destructing: SpawnInDestructor
 Spawning coroutine in destructor
 Waiting for coroutine in destructor
-Main coroutine running
 Coroutine running in destructor
-Main coroutine resumed
 Coroutine resumed in destructor
 Coroutine completed with: destructor coroutine done
 Destructor finished: SpawnInDestructor

tests/edge_cases/011-gc_include_symtable_double_delref.phpt

@@ -0,0 +1,53 @@
+--TEST--
+GC with include in suspended coroutine - symTable double DELREF
+--FILE--
+<?php
+
+use function Async\spawn;
+use function Async\suspend;
+use function Async\await;
+
+class Cycle {
+    public $self;
+}
+
+try {
+    $coroutine = spawn(function() {
+        $parent1 = "value1";
+        $parent2 = "value2";
+
+        for ($i = 0; $i < 10000; $i++) {
+            $obj = new Cycle();
+            $obj->self = $obj;
+        }
+
+        // Suspend - coroutine is now in suspended state
+        suspend();
+
+        // Include inherits parent symTable
+        // Bug: GC may add same variables twice -> double DELREF
+        include __DIR__ . '/011-gc_include_symtable_double_delref_included.inc';
+
+        echo "parent1: {$parent1}\n";
+        echo "parent2: {$parent2}\n";
+        echo "included: {$included}\n";
+
+        return "done";
+    });
+
+    $result = await($coroutine);
+    echo "result: {$result}\n";
+
+} catch (Error $e) {
+    echo "Error: " . $e->getMessage() . "\n";
+}
+
+echo "OK\n";
+gc_collect_cycles();
+?>
+--EXPECTF--
+parent1: value1
+parent2: value2
+included: included_value
+result: done
+OK

tests/edge_cases/011-gc_include_symtable_double_delref_included.inc

@@ -0,0 +1,3 @@
+<?php
+// Included file for GC test
+$included = "included_value";