Parameter 1 to imagefield_widget() expected to be a reference, value given in .../module.inc on lin

I had this problem. Because of a different error users reported success by adding manual module_load_invoke() calls in this module. However now parts of the module are loaded twice after solved the original problem by editing /etc/php5/apache2/conf.d/apc.ini and changing the following line from 1 to 0:

apc.include_once_override = 0

Restart apache. Now include/require_once calls are not overridden, they will work properly. Remove all customizations to the filefield module by using the original files. Then the problem disappeared for me.

> Parameter 1 to imagefield_widget() expected to be a reference, value given in .../includes/module.inc on line 476

Well I haven't seen this problem myself. I think it's likely to be a PHP configuration issue like #2 suggests. However we can easily fix this exact error by fixing exactly what has been described (that a reference was expected but a value came in). I've committed this patch, hopefully it will help with your situation. It'll be in the 3.11 that will be coming out shortly.

Hm, actually I had to roll #4 back. Passing the $form by reference is required to validate required values properly.

If you can give me instructions on reproducing the problem I'll have another look. Right now I don't have any ability to discover where this problem originates.

I had patched my own site before finding this. I have image_fupload installed, and when you go back to edit a node that already has images I was seeing the above warning, and no images showing on the node edit page.

However, applying the patch in #4 above just shifted the warning to Parameter 2 when I tried it. Removing both allows for the images to show up.

I see if there is anything else I can find from my end.

This is likely an issue with image_fupload. Check out patch at #619632-42: PHP5.3 error: warning: Parameter 1 to imagefield_widget() expected to be a reference and see if that fixes the issue.