Prevent switching fibers in tick function

Author: trowski

Zend/tests/fibers/ticks.phpt

@@ -0,0 +1,33 @@
+--TEST--
+Prevent switchcing fibers in tick function
+--FILE--
+<?php
+
+declare(ticks=1);
+
+register_tick_function(function (): void {
+    if (Fiber::getCurrent() !== null) {
+        Fiber::suspend();
+    }
+});
+
+$fiber = new Fiber(function (): void {
+    echo "1\n";
+    echo "2\n";
+    echo "3\n";
+});
+
+$fiber->start();
+
+?>
+--EXPECTF--
+1
+
+Fatal error: Uncaught FiberError: Cannot switch fibers in current execution context in %sticks.php:%d
+Stack trace:
+#0 %sticks.php(%d): Fiber::suspend()
+#1 %sticks.php(%d): {closure}()
+#2 [internal function]: {closure}()
+#3 %sticks.php(%d): Fiber->start()
+#4 {main}
+  thrown in %sticks.php on line %d

Zend/zend_vm_def.h

@@ -7752,7 +7752,9 @@ ZEND_VM_HANDLER(105, ZEND_TICKS, ANY, ANY, NUM)
 		EG(ticks_count) = 0;
 		if (zend_ticks_function) {
 			SAVE_OPLINE();
+			zend_fiber_switch_block();
 			zend_ticks_function(opline->extended_value);
+			zend_fiber_switch_unblock();
 			ZEND_VM_NEXT_OPCODE_CHECK_EXCEPTION();
 		}
 	}