Call to a member function register_field_type() on null on line 204 in advanced-custom-fields/includes/fields.php about acf HOT 6 CLOSED

Hi @djvdorp

Thanks for the bug report.
I'm not able to replicate this from my end, are you able to setup a fresh WP install without an other plugins and see if the issue persists?

from acf.

Hi @elliotcondon

Sorry for the delayed reply. I haven't been able to reproduce the issue somewhere else yet, so it could potentially be related to another plugin or some setting that is off. I want to investigate this further soon!

from acf.

Hi @elliotcondon

We found out that it is likely related to a plugin we're using, vBLink.
Please correct me if we're wrong, but it looks like this could be what is happening:

• ACF uses a global instance of itself, which somehow gets broken when vBLink is enabled
• ACF initializes itself in 2 hooks: first when plugins are loaded and then in init
• it looks like vBLink makes ACF lose the global instance that ACF uses for itself
• what happens then is that only init is run and not initialize which causes some fields to not be there
• that results in above error

We were able to find a (horrible) work-around for this, which is rather dirty but works:

[...]

// BEGIN VBLINK CODE
// making a backup so we can reassign values to their originals after it is loaded.
$requestSuperglobals = array($_GET, $_POST, $_REQUEST);
// END VBLINK CODE

// WORKAROUND: Ugly fix for not breaking page save due error in ACF
$saveAcf = $GLOBALS['acf'];

[...]

// BEGIN VBLINK CODE
list($_GET, $_POST, $_REQUEST) = $requestSuperglobals; <-- vBLink code
// END VBLINK CODE

// WORKAROUND: Restore ACF
$GLOBALS['acf'] = $saveAcf;

[...]

Since vBLink is not open source software, I can most likely not paste (all of the) the exact code, but I hope the above description makes sense to you to give you an idea what happens and what goes wrong here.

from acf.

Hi @djvdorp

Thanks for the reply and info.

ACF does use a global variable called $acf, and this is initialized at the end of the main acf.php file via the function acf();

I'm not sure why the vBLink plugin would be causing such an issue, but this will definitely be something the developers should be aware of - can you please contact them and let them know?

Thanks
Elliot

from acf.

Hi @elliotcondon

I would love to hit up the vBlink developers and inform them about this, but I am having a very hard time reaching them currently. I mostly wanted to share the workaround here for others right now.
I am closing this issue since I don't think there is much that you (on behalf of ACF) can do about this?

from acf.

After updating to latest ACF, faced same issue and thanks to @djvdorp for the tricky solution :)

from acf.