JPluginHelper::importPlugin() method does not load the same plugin with two different dispatchers

[iv660]

Steps to reproduce the issue

Call JPluginHelper::importPlugin() with two unique instances of JEventDispatcher class:

    $type = 'quickicon';
    
    $dispatcher1 = new JEventDispatcher();
    $dispatcher2 = new JEventDispatcher();
    JPluginHelper::importPlugin($type, null, true, $dispatcher1);
    JPluginHelper::importPlugin($type, null, true, $dispatcher2);
    echo "<p>Dispatcher1:</p>"; ##
    echo "<pre>"; ##
    print_r($dispatcher1); ##
    echo "</pre>"; ##
    echo "<p>Dispatcher2:</p>"; ##
    echo "<pre>"; ##
    print_r($dispatcher2); ##
    echo "</pre>"; ##

Expected result

Both dispatchers should be identical, with plugins loaded as observers:

Dispatcher1:

JEventDispatcher Object
(
    [_observers:protected] => Array
        (
            [0] => PlgQuickiconJoomlaupdate Object
                (
                    [autoloadLanguage:protected] => 1
                    [params] => Joomla\Registry\Registry Object
                        (
                            [data:protected] => stdClass Object
                                (
                                )

                            [initialized:protected] => 1
                            [separator] => .
                        )

                    [_name:protected] => joomlaupdate
                    [_type:protected] => quickicon
                    [_subject:protected] => JEventDispatcher Object
 *RECURSION*
                    [_errors:protected] => Array
                        (
                        )

                )

            [1] => PlgQuickiconExtensionupdate Object
                (
                    [autoloadLanguage:protected] => 1
                    [params] => Joomla\Registry\Registry Object
                        (
                            [data:protected] => stdClass Object
                                (
                                )

                            [initialized:protected] => 1
                            [separator] => .
                        )

                    [_name:protected] => extensionupdate
                    [_type:protected] => quickicon
                    [_subject:protected] => JEventDispatcher Object
 *RECURSION*
                    [_errors:protected] => Array
                        (
                        )

                )

        )

    [_state:protected] => 
    [_methods:protected] => Array
        (
            [ongeticons] => Array
                (
                    [0] => 0
                    [1] => 1
                )

        )
 
    [_errors:protected] => Array
        (
         )
 
)
Dispatcher2:

JEventDispatcher Object
(
    [_observers:protected] => Array
        (
            [0] => PlgQuickiconJoomlaupdate Object
                (
                    [autoloadLanguage:protected] => 1
                    [params] => Joomla\Registry\Registry Object
                        (
                            [data:protected] => stdClass Object
                                (
                                )

                            [initialized:protected] => 1
                            [separator] => .
                        )

                    [_name:protected] => joomlaupdate
                    [_type:protected] => quickicon
                    [_subject:protected] => JEventDispatcher Object
 *RECURSION*
                    [_errors:protected] => Array
                        (
                        )

                )

            [1] => PlgQuickiconExtensionupdate Object
                (
                    [autoloadLanguage:protected] => 1
                    [params] => Joomla\Registry\Registry Object
                        (
                            [data:protected] => stdClass Object
                                (
                                )

                            [initialized:protected] => 1
                            [separator] => .
                        )

                    [_name:protected] => extensionupdate
                    [_type:protected] => quickicon
                    [_subject:protected] => JEventDispatcher Object
 *RECURSION*
                    [_errors:protected] => Array
                        (
                        )

                )

        )

    [_state:protected] => 
    [_methods:protected] => Array
        (
            [ongeticons] => Array
                (
                    [0] => 0
                    [1] => 1
                )

        )

    [_errors:protected] => Array
        (
        )

)

Actual result

Second dispatcher has no observers loaded:

Dispatcher1:

JEventDispatcher Object
(
    [_observers:protected] => Array
        (
            [0] => PlgQuickiconJoomlaupdate Object
                (
                    [autoloadLanguage:protected] => 1
                    [params] => Joomla\Registry\Registry Object
                        (
                            [data:protected] => stdClass Object
                                (
                                )

                            [initialized:protected] => 1
                            [separator] => .
                        )

                    [_name:protected] => joomlaupdate
                    [_type:protected] => quickicon
                    [_subject:protected] => JEventDispatcher Object
 *RECURSION*
                    [_errors:protected] => Array
                        (
                        )

                )

            [1] => PlgQuickiconExtensionupdate Object
                (
                    [autoloadLanguage:protected] => 1
                    [params] => Joomla\Registry\Registry Object
                        (
                            [data:protected] => stdClass Object
                                (
                                )

                            [initialized:protected] => 1
                            [separator] => .
                        )

                    [_name:protected] => extensionupdate
                    [_type:protected] => quickicon
                    [_subject:protected] => JEventDispatcher Object
 *RECURSION*
                    [_errors:protected] => Array
                        (
                        )

                )

        )

    [_state:protected] => 
    [_methods:protected] => Array
        (
            [ongeticons] => Array
                (
                    [0] => 0
                    [1] => 1
                )

        )

    [_errors:protected] => Array
        (
        )

)

Dispatcher2:

JEventDispatcher Object
(
    [_observers:protected] => Array
        (
        )

    [_state:protected] => 
    [_methods:protected] => Array
        (
        )

    [_errors:protected] => Array
        (
        )

)

System information (as much as possible)

Platform Windows NT KEY 6.1 build 7601 (Windows 7 Business Edition Service Pack 1) i586
DB 5.5.38-log
DB encoding utf8_general_ci
DB connection encoding utf8mb4_general_ci
PHP version 5.4.29
Web-server Apache/2.2.27 (Win32)
apache2handler
Joomla! 3.6.4 Stable [ Noether ] 21-October-2016 16:33 GMT
Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0

Additional comments

The ability to load the plugin with individual dispatchers is important when dealing with extension-specific plugins. It is the way to run the plugins from the specific plugin group(s) in isolation from the "system-wide" plugins.

[ghost]

@iv660 is this Issue on latest Staging too?

---

_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/12690.}

[iv660]

@franz-wohlkoenig I'm not sure if I've got your question right, but if you are talking about Joomla! 3.6.5, sorry, I didn't have a chance to check yet.

[zero-24]

@iv660 3.6.5 or https://github.com/joomla/joomla-cms/tree/staging the staging branch 😄

[zero-24]

but it is still the same behavior on staging (just checked) using your code above.

[mbabker]

To fix this, the static loaded array is going to need to become an associative array with the key being a hash of the injected dispatcher (or whatever the default one is when the param is null) and it holds an array of the loaded plugins for that dispatcher.

[mbabker]

See #15607