Warning：strcmp() expects parameter 2 to be string, array given in _system_sort_requirements

It's fbconnect. This module and several others are affected by #933684: Same requirements from different modules causes warnings in _system_sort_requirements(). Until that is resolved, modules implementing hook_requirements need to namespace the keys in their requirements array to avoid clashes with other modules.

Other modules which return 'curl' include

* Linkedin Integration (#1711604: On installation errors reported from system.module and system.admin.inc)
* Simpletest (#1983132: Multiple warnings when Simplepie enabled "Warning: strcmp() expects parameter 1 to be string...")
* FBConnect (#2456757: Namespace requirement keys in hook_requirements())

Thanks for the heads up!

@e0ipso - in case it wasn't clear, I suspect your module (along with those others) is having a conflict with other modules, resolvable by namespacing the keys returned from hook_requirements.

Instead of returning a key of 'facebook-php-sdk' which is also returned by other modules, you could return a key of 'fb_autopost-facebook-php-sdk', which won't trigger the conflict.

I don't use this module so I'm not certain your module is actually affected, but it's harmless and probably good practice to address it until #933684: Same requirements from different modules causes warnings in _system_sort_requirements() is resolved in 8.x

(I won't care if you close this again, but reopening to put it back on your radar.)