Do not scan generator frames more than once

Zend/tests/gh15330-001.phpt

@@ -0,0 +1,38 @@
+--TEST--
+GH-15330 001: Do not scan generator frames more than once
+--FILE--
+<?php
+
+class It implements \IteratorAggregate
+{
+    public function getIterator(): \Generator
+    {
+        yield 'foo';
+        Fiber::suspend();
+        var_dump("not executed");
+    }
+}
+
+function f() {
+    var_dump(yield from new It());
+}
+
+$iterable = f();
+
+$fiber = new Fiber(function () use ($iterable) {
+    var_dump($iterable->current());
+    $iterable->next();
+    var_dump("not executed");
+});
+
+$ref = $fiber;
+
+$fiber->start();
+
+gc_collect_cycles();
+
+?>
+==DONE==
+--EXPECT--
+string(3) "foo"
+==DONE==

Zend/tests/gh15330-002.phpt

@@ -0,0 +1,33 @@
+--TEST--
+GH-15330 002: Do not scan generator frames more than once
+--FILE--
+<?php
+
+function g() {
+    yield 'foo';
+    Fiber::suspend();
+}
+
+function f() {
+    var_dump(yield from g());
+}
+
+$iterable = f();
+
+$fiber = new Fiber(function () use ($iterable) {
+    var_dump($iterable->current());
+    $iterable->next();
+    var_dump("not executed");
+});
+
+$ref = $fiber;
+
+$fiber->start();
+
+gc_collect_cycles();
+
+?>
+==DONE==
+--EXPECT--
+string(3) "foo"
+==DONE==

Zend/tests/gh15330-003.phpt

@@ -0,0 +1,57 @@
+--TEST--
+GH-15330 003: Do not scan generator frames more than once
+--FILE--
+<?php
+
+class It implements \IteratorAggregate
+{
+    public function getIterator(): \Generator
+    {
+        yield 'foo';
+        Fiber::suspend();
+        var_dump("not executed");
+    }
+}
+
+class Canary {
+    public function __construct(public mixed $value) {}
+    public function __destruct() {
+        var_dump(__METHOD__);
+    }
+}
+
+function f($canary) {
+    var_dump(yield from new It());
+}
+
+$canary = new Canary(null);
+
+$iterable = f($canary);
+
+$fiber = new Fiber(function () use ($iterable, $canary) {
+    var_dump($canary, $iterable->current());
+    $iterable->next();
+    var_dump("not executed");
+});
+
+$canary->value = $fiber;
+
+$fiber->start();
+
+$iterable->current();
+
+$fiber = $iterable = $canary = null;
+
+gc_collect_cycles();
+
+?>
+==DONE==
+--EXPECTF--
+object(Canary)#%d (1) {
+  ["value"]=>
+  object(Fiber)#%d (0) {
+  }
+}
+string(3) "foo"
+string(18) "Canary::__destruct"
+==DONE==

Zend/tests/gh15330-004.phpt

@@ -0,0 +1,52 @@
+--TEST--
+GH-15330 004: Do not scan generator frames more than once
+--FILE--
+<?php
+
+class Canary {
+    public function __construct(public mixed $value) {}
+    public function __destruct() {
+        var_dump(__METHOD__);
+    }
+}
+
+function g() {
+    yield 'foo';
+    Fiber::suspend();
+}
+
+function f($canary) {
+    var_dump(yield from g());
+}
+
+$canary = new Canary(null);
+
+$iterable = f($canary);
+
+$fiber = new Fiber(function () use ($iterable, $canary) {
+    var_dump($canary, $iterable->current());
+    $iterable->next();
+    var_dump("not executed");
+});
+
+$canary->value = $fiber;
+
+$fiber->start();
+
+$iterable->current();
+
+$fiber = $iterable = $canary = null;
+
+gc_collect_cycles();
+
+?>
+==DONE==
+--EXPECTF--
+object(Canary)#%d (1) {
+  ["value"]=>
+  object(Fiber)#%d (0) {
+  }
+}
+string(3) "foo"
+string(18) "Canary::__destruct"
+==DONE==

Zend/tests/gh15330-005.phpt

@@ -0,0 +1,53 @@
+--TEST--
+GH-15330 005: Do not scan generator frames more than once
+--FILE--
+<?php
+
+class Canary {
+    public function __construct(public mixed $value) {}
+    public function __destruct() {
+        var_dump(__METHOD__);
+    }
+}
+
+function g() {
+    yield 'foo';
+    Fiber::suspend();
+}
+
+function f($canary) {
+    var_dump(yield from g());
+}
+
+$canary = new Canary(null);
+
+$iterable = f($canary);
+
+$fiber = new Fiber(function () use ($iterable, $canary) {
+    var_dump($canary, $iterable->current());
+    $f = $iterable->next(...);
+    $f();
+    var_dump("not executed");
+});
+
+$canary->value = $fiber;
+
+$fiber->start();
+
+$iterable->current();
+
+$fiber = $iterable = $canary = null;
+
+gc_collect_cycles();
+
+?>
+==DONE==
+--EXPECTF--
+object(Canary)#%d (1) {
+  ["value"]=>
+  object(Fiber)#%d (0) {
+  }
+}
+string(3) "foo"
+string(18) "Canary::__destruct"
+==DONE==

Zend/tests/gh15330-006.phpt

@@ -0,0 +1,56 @@
+--TEST--
+GH-15330 006: Do not scan generator frames more than once
+--FILE--
+<?php
+
+class Canary {
+    public function __construct(public mixed $value) {}
+    public function __destruct() {
+        var_dump(__METHOD__);
+    }
+}
+
+function h() {
+    yield 'foo';
+    Fiber::suspend();
+}
+
+function g() {
+    yield from h();
+}
+
+function f($canary) {
+    var_dump(yield from g());
+}
+
+$canary = new Canary(null);
+
+$iterable = f($canary);
+
+$fiber = new Fiber(function () use ($iterable, $canary) {
+    var_dump($canary, $iterable->current());
+    $iterable->next();
+    var_dump("not executed");
+});
+
+$canary->value = $fiber;
+
+$fiber->start();
+
+$iterable->current();
+
+$fiber = $iterable = $canary = null;
+
+gc_collect_cycles();
+
+?>
+==DONE==
+--EXPECTF--
+object(Canary)#%d (1) {
+  ["value"]=>
+  object(Fiber)#%d (0) {
+  }
+}
+string(3) "foo"
+string(18) "Canary::__destruct"
+==DONE==

Zend/zend_execute.c

@@ -4437,7 +4437,20 @@ ZEND_API ZEND_ATTRIBUTE_DEPRECATED HashTable *zend_unfinished_execution_gc(zend_
 
 ZEND_API HashTable *zend_unfinished_execution_gc_ex(zend_execute_data *execute_data, zend_execute_data *call, zend_get_gc_buffer *gc_buffer, bool suspended_by_yield)
 {
-	if (!EX(func) || !ZEND_USER_CODE(EX(func)->common.type)) {
+	if (!EX(func)) {
+		return NULL;
+	}
+
+	if (EX_CALL_INFO() & ZEND_CALL_RELEASE_THIS) {
+		zend_get_gc_buffer_add_obj(gc_buffer, Z_OBJ(execute_data->This));
+	}
+
+	if (EX_CALL_INFO() & ZEND_CALL_CLOSURE) {
+		zend_get_gc_buffer_add_obj(gc_buffer, ZEND_CLOSURE_OBJECT(EX(func)));
+	}
+
+	if (!ZEND_USER_CODE(EX(func)->common.type)) {
+		ZEND_ASSERT(!(EX_CALL_INFO() & (ZEND_CALL_HAS_SYMBOL_TABLE|ZEND_CALL_FREE_EXTRA_ARGS|ZEND_CALL_HAS_EXTRA_NAMED_PARAMS)));
 		return NULL;
 	}
 
@@ -4458,12 +4471,6 @@ ZEND_API HashTable *zend_unfinished_execution_gc_ex(zend_execute_data *execute_d
 		}
 	}
 
-	if (EX_CALL_INFO() & ZEND_CALL_RELEASE_THIS) {
-		zend_get_gc_buffer_add_obj(gc_buffer, Z_OBJ(execute_data->This));
-	}
-	if (EX_CALL_INFO() & ZEND_CALL_CLOSURE) {
-		zend_get_gc_buffer_add_obj(gc_buffer, ZEND_CLOSURE_OBJECT(EX(func)));
-	}
 	if (EX_CALL_INFO() & ZEND_CALL_HAS_EXTRA_NAMED_PARAMS) {
 		zval extra_named_params;
 		ZVAL_ARR(&extra_named_params, EX(extra_named_params));

Zend/zend_fibers.c

@@ -19,6 +19,7 @@
 
 #include "zend.h"
 #include "zend_API.h"
+#include "zend_gc.h"
 #include "zend_ini.h"
 #include "zend_vm.h"
 #include "zend_exceptions.h"
@@ -27,6 +28,7 @@
 #include "zend_mmap.h"
 #include "zend_compile.h"
 #include "zend_closures.h"
+#include "zend_generators.h"
 
 #include "zend_fibers.h"
 #include "zend_fibers_arginfo.h"
@@ -682,7 +684,25 @@ static HashTable *zend_fiber_object_gc(zend_object *object, zval **table, int *n
 	HashTable *lastSymTable = NULL;
 	zend_execute_data *ex = fiber->execute_data;
 	for (; ex; ex = ex->prev_execute_data) {
-		HashTable *symTable = zend_unfinished_execution_gc_ex(ex, ex->func && ZEND_USER_CODE(ex->func->type) ? ex->call : NULL, buf, false);
+		HashTable *symTable;
+		if (ZEND_CALL_INFO(ex) & ZEND_CALL_GENERATOR) {
+			/* The generator object is stored in ex->return_value */
+			zend_generator *generator = (zend_generator*)ex->return_value;
+			/* There are two cases to consider:
+			 * - If the generator is currently running, the Generator's GC
+			 *   handler will ignore it because it is not collectable. However,
+			 *   in this context the generator is suspended in Fiber::suspend()
+			 *   and may be collectable, so we can inspect it.
+			 * - If the generator is not running, the Generator's GC handler
+			 *   will inspect it. In this case we have to skip the frame.
+			 */
+			if (!(generator->flags & ZEND_GENERATOR_CURRENTLY_RUNNING)) {
+				continue;
+			}
+			symTable = zend_generator_frame_gc(buf, generator);
+		} else {
+			symTable = zend_unfinished_execution_gc_ex(ex, ex->func && ZEND_USER_CODE(ex->func->type) ? ex->call : NULL, buf, false);
+		}
 		if (symTable) {
 			if (lastSymTable) {
 				zval *val;