Zend: zend_fiber_execute() discards exit() in a destroyed fiber.

Fix #24265

A destroyed fiber swallowed UnwindExit along with the GracefulExit used
to unwind it, so exit() in a finally block or destructor was lost. Only
the GracefulExit is swallowed now.

Author: devnexen

Zend/tests/fibers/gh24265-001.phpt

@@ -0,0 +1,24 @@
+--TEST--
+GH-24265 (exit() in a finally block of a destroyed fiber is discarded)
+--CREDITS--
+iluuu1994
+--FILE--
+<?php
+
+$fiber = new Fiber(function () {
+    try {
+        Fiber::suspend();
+    } finally {
+        exit(1);
+    }
+});
+
+$fiber->start();
+echo "Before destroy", PHP_EOL;
+unset($fiber);
+
+echo "Not reached", PHP_EOL;
+
+?>
+--EXPECT--
+Before destroy

Zend/tests/fibers/gh24265-002.phpt

@@ -0,0 +1,30 @@
+--TEST--
+GH-24265 (exit() in a destroyed fiber is discarded while an exception is pending)
+--FILE--
+<?php
+
+function test() {
+    $fiber = new Fiber(function () {
+        try {
+            Fiber::suspend();
+        } finally {
+            exit(1);
+        }
+    });
+
+    $fiber->start();
+    echo "Before destroy", PHP_EOL;
+    throw new Exception("pending");
+}
+
+try {
+    test();
+} catch (Exception $e) {
+    echo $e::class, ': ', $e->getMessage(), PHP_EOL;
+}
+
+echo "Not reached", PHP_EOL;
+
+?>
+--EXPECT--
+Before destroy

Zend/zend_fibers.c

@@ -613,9 +613,7 @@ static ZEND_STACK_ALIGNED void zend_fiber_execute(zend_fiber_transfer *transfer)
 		ZVAL_UNDEF(&fiber->fci.function_name);
 
 		if (EG(exception)) {
-			if (!(fiber->flags & ZEND_FIBER_FLAG_DESTROYED)
-				|| !(zend_is_graceful_exit(EG(exception)) || zend_is_unwind_exit(EG(exception)))
-			) {
+			if (!(fiber->flags & ZEND_FIBER_FLAG_DESTROYED) || !zend_is_graceful_exit(EG(exception))) {
 				fiber->flags |= ZEND_FIBER_FLAG_THREW;
 				transfer->flags = ZEND_FIBER_TRANSFER_FLAG_ERROR;
 
@@ -797,7 +795,11 @@ static void zend_fiber_object_destroy(zend_object *object)
 			zend_rethrow_exception(EG(current_execute_data));
 		}
 
-		zend_exception_set_previous(EG(exception), exception);
+		if (exception && zend_is_unwind_exit(EG(exception))) {
+			OBJ_RELEASE(exception);
+		} else {
+			zend_exception_set_previous(EG(exception), exception);
+		}
 
 		if (!EG(current_execute_data)) {
 			zend_exception_error(EG(exception), E_ERROR);