Problem handling Class Inheritance

[juan-morales]

This issue is related to #386 , but enriched.

I dont know if the problem is in v8js or v8, I tried hard to follow the code of the extension and I have my doubts.

Code that produces the error:

class BaseClass {
        public function bla() {
            echo "print bla";
        }
}

class Foo extends BaseClass {}

class Bar extends BaseClass {}

$v8 = new V8Js('PHP');
$v8->Foo = new Foo();
$v8->Bar = new Bar();

$code = <<<EOT
var_dump(PHP.Foo);
PHP.Foo.bla();
var_dump(PHP.Bar);
PHP.Bar.bla();
EOT;

//$resourceScript = $v8->compileString($code);
$v8->executeString($code);

Execution Output:

object(Foo)#1515588 (1) {
  ["bla"] =>
  object(Closure)#1289866 {
      function () { [native code] }
  }
}
print blaobject(Bar)#259312 (1) {
  ["bla"] =>
  object(Closure)#1289866 {
      function () { [native code] }
  }
}
PHP Fatal error:  Uncaught V8JsScriptException: V8Js::compileString():4: TypeError: Illegal invocation in /home/user/testv8.php:25
Stack trace:
#0 /home/user/testv8.php(25): V8Js->executeString('var_dump(PHP.Fo...')
#1 {main}
  thrown in /home/user/testv8.php on line 25

Fatal error: Uncaught V8JsScriptException: V8Js::compileString():4: TypeError: Illegal invocation in /home/user/testv8.php on line 25

V8JsScriptException: V8Js::compileString():4: TypeError: Illegal invocation in /home/user/testv8.php on line 25

Call Stack:
    0.0001     394408   1. {main}() /home/user/testv8.php:0
    0.0080     395744   2. V8Js->executeString() /home/user/testv8.php:25

Tip 1 - If we just compile ... everything looks ok
(Just look at the end of the code snippet and un/comment as showed here)

$resourceScript = $v8->compileString($code);
//$v8->executeString($code);

Execution output: Nothing (ok?)

Ok, solutions/workarounds ?

1) Use __call to call methods in class

class BaseClass {
        public function bla() {
            echo "print bla";
        }
}

class Foo extends BaseClass {}

class Bar extends BaseClass {}

$v8 = new V8Js('PHP');
$v8->Foo = new Foo();
$v8->Bar = new Bar();

$code = <<<EOT
var_dump(PHP.Foo);
PHP.Foo.__call("bla", []);
var_dump(PHP.Bar);
PHP.Bar.__call("bla", []);
EOT;

//$resourceScript = $v8->compileString($code);
$v8->executeString($code);

2) Re-declare your derived clases like so:

class BaseClass {
        public function bla() {
            echo "print bla";
        }
}

class Foo extends BaseClass {
        public function bla() {
            parent::bla();
        }    
}

class Bar extends BaseClass {
        public function bla() {
            parent::bla();
        }
}

$v8 = new V8Js('PHP');
$v8->Foo = new Foo();
$v8->Bar = new Bar();

$code = <<<EOT
var_dump(PHP.Foo);
PHP.Foo.bla();
var_dump(PHP.Bar);
PHP.Bar.bla();
EOT;

//$resourceScript = $v8->compileString($code);
$v8->executeString($code);

My environment:

OS: LINUX UBUNTU

Linux user 4.18.0-20-generic #21~18.04.1-Ubuntu SMP Wed May 8 08:43:37 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

PHP info

php -v
PHP 7.2.19-0ubuntu0.18.04.1 (cli) (built: Jun  4 2019 14:48:12) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.2.19-0ubuntu0.18.04.1, Copyright (c) 1999-2018, by Zend Technologies

V8JS info

$ php --ri v8js

V8 Javascript Engine => enabled
V8 Engine Compiled Version => 7.6.57
V8 Engine Linked Version => 7.6.57
Version => 2.1.0

Directive => Local Value => Master Value
v8js.flags => no value => no value
v8js.icudtl_dat_path => no value => no value
v8js.use_date => 0 => 0
v8js.use_array_access => 0 => 0**

I hope to get a better understanding regarding this.

[stesie]

Interesting catch, it's related to the v8::FunctionTemplate reuse/caching. If you comment it out like this:

diff --git a/v8js_object_export.cc b/v8js_object_export.cc
index b36574c..0aaa0e3 100644
--- a/v8js_object_export.cc
+++ b/v8js_object_export.cc
@@ -699,11 +699,11 @@ v8::Local<v8::Value> v8js_named_property_callback(v8::Local<v8::Name> property_n
                                        }
                                } else {
                                        v8::Local<v8::FunctionTemplate> ft;
-                                       try {
+                                       /* try {
                                                ft = v8::Local<v8::FunctionTemplate>::New
                                                        (isolate, ctx->method_tmpls.at(method_ptr));
                                        }
-                                       catch (const std::out_of_range &) {
+                                       catch (const std::out_of_range &)  */ {
                                                ft = v8::FunctionTemplate::New(isolate, v8js_php_callback,
                                                                v8::External::New((isolate), method_ptr),
                                                                v8::Signature::New((isolate), tmpl));

... it works :)

Of course this is not a proper solution, but shows the cause of the problem. The cache is solely based on method_ptr, which is the zend_function * to call.

[juan-morales]

thanks @stesie