Fix GH-10011 (Trampoline autoloader will get reregistered and cannot be unregistered)

There are two issues to resolve:
 1. The FCC is not refetch when trying to unregister a trampoline
 2. Comparing the function pointer of trampolines is meaningless as they are reallocated, thus we need to compare the name of the function

Found while working on GH-8294

Closes GH-10033

Author: Girgias

NEWS

@@ -9,7 +9,6 @@ PHP                                                                        NEWS
     README.REDIST.BINS file). (Akama Hitoshi)
   . Fixed bug GH-9650 (Can't initialize heap: [0x000001e7]). (Michael Voříšek)
   . Fixed potentially undefined behavior in Windows ftok(3) emulation. (cmb)
-  . Fixed GH-9769 (Misleading error message for unpacking of objects). (jhdxr)
 
 - Date:
   . Fixed bug GH-9699 (DateTimeImmutable::diff differences in 8.1.10 onwards -
@@ -55,6 +54,8 @@ PHP                                                                        NEWS
 
 - SPL:
   . Fixed GH-9883 (SplFileObject::__toString() reads next line). (Girgias)
+  . Fixed GH-10011 (Trampoline autoloader will get reregistered and cannot be
+    unregistered). (Girgias)
 
 24 Nov 2022, PHP 8.1.13
 

ext/spl/php_spl.c

@@ -402,6 +402,16 @@ static autoload_func_info *autoload_func_info_from_fci(
 
 static bool autoload_func_info_equals(
 		const autoload_func_info *alfi1, const autoload_func_info *alfi2) {
+	if (UNEXPECTED(
+		(alfi1->func_ptr->common.fn_flags & ZEND_ACC_CALL_VIA_TRAMPOLINE) &&
+		(alfi2->func_ptr->common.fn_flags & ZEND_ACC_CALL_VIA_TRAMPOLINE)
+	)) {
+		return alfi1->obj == alfi2->obj
+			&& alfi1->ce == alfi2->ce
+			&& alfi1->closure == alfi2->closure
+			&& zend_string_equals(alfi1->func_ptr->common.function_name, alfi2->func_ptr->common.function_name)
+		;
+	}
 	return alfi1->func_ptr == alfi2->func_ptr
 		&& alfi1->obj == alfi2->obj
 		&& alfi1->ce == alfi2->ce
@@ -580,6 +590,13 @@ PHP_FUNCTION(spl_autoload_unregister)
 		RETURN_TRUE;
 	}
 
+	if (!fcc.function_handler) {
+		/* Call trampoline has been cleared by zpp. Refetch it, because we want to deal
+		 * with it outselves. It is important that it is not refetched on every call,
+		 * because calls may occur from different scopes. */
+		zend_is_callable_ex(&fci.function_name, NULL, 0, NULL, &fcc, NULL);
+	}
+
 	autoload_func_info *alfi = autoload_func_info_from_fci(&fci, &fcc);
 	Bucket *p = spl_find_registered_function(alfi);
 	autoload_func_info_destroy(alfi);

ext/spl/tests/gh10011.phpt

@@ -0,0 +1,59 @@
+--TEST--
+Bug GH-10011 (Trampoline autoloader will get reregistered and cannot be unregistered)
+--FILE--
+<?php
+
+class TrampolineTest {
+    public function __call(string $name, array $arguments) {
+        echo 'Trampoline for ', $name, PHP_EOL;
+    }
+}
+$o = new TrampolineTest();
+$callback1 = [$o, 'trampoline1'];
+$callback2 = [$o, 'trampoline2'];
+
+spl_autoload_register($callback1);
+spl_autoload_register($callback2);
+spl_autoload_register($callback1); // 2nd call ignored
+
+var_dump(spl_autoload_functions());
+
+var_dump(class_exists("TestClass", true));
+
+echo "Unregister trampoline:\n";
+var_dump(spl_autoload_unregister($callback1));
+var_dump(spl_autoload_unregister($callback1));
+var_dump(spl_autoload_unregister($callback2));
+
+var_dump(spl_autoload_functions());
+var_dump(class_exists("TestClass", true));
+?>
+--EXPECT--
+array(2) {
+  [0]=>
+  array(2) {
+    [0]=>
+    object(TrampolineTest)#1 (0) {
+    }
+    [1]=>
+    string(11) "trampoline1"
+  }
+  [1]=>
+  array(2) {
+    [0]=>
+    object(TrampolineTest)#1 (0) {
+    }
+    [1]=>
+    string(11) "trampoline2"
+  }
+}
+Trampoline for trampoline1
+Trampoline for trampoline2
+bool(false)
+Unregister trampoline:
+bool(true)
+bool(false)
+bool(true)
+array(0) {
+}
+bool(false)