Problems with Add to cart

[xavitriu]

As other users happen to them, sometimes we can't add products to the shopping cart. It goes to an "empty cart".

We have instrumented the addAction method in CartController like this:

public function addAction() {
Mage::log('AddAction: 1a Start: '.$this->getRequest()->getParam('form_key', 'null').";");
Mage::log('AddAction: 1b Start: '.Mage::getSingleton('core/session')->getFormKey().";");

And we observe that when we have this module enabled the logs we obtain is:

2016-11-21T13:40:03+00:00 DEBUG (7): AddAction: 1a Start: gELlVR6h6R9z1bQ1;
2016-11-21T13:40:03+00:00 DEBUG (7): AddAction: 1b Start: qKENHGY5iJRrkuYB;

2016-11-21T13:40:16+00:00 DEBUG (7): AddAction: 1a Start: Xs3xRkkwnVxd8P3n;
2016-11-21T13:40:16+00:00 DEBUG (7): AddAction: 1b Start: qKENHGY5iJRrkuYB;

2016-11-21T13:40:47+00:00 DEBUG (7): AddAction: 1a Start: gELlVR6h6R9z1bQ1;
2016-11-21T13:40:47+00:00 DEBUG (7): AddAction: 1b Start: qKENHGY5iJRrkuYB;

We observe that the formkey provided by the magento session is the same in every interaction.
If we disable your module, we get the following pairs of logs:

2016-11-21T13:45:49+00:00 DEBUG (7): AddAction: 1a Start: Ajm7MVeSUyZgDQE3;
2016-11-21T13:45:49+00:00 DEBUG (7): AddAction: 1b Start: Ajm7MVeSUyZgDQE3;

2016-11-21T13:46:15+00:00 DEBUG (7): AddAction: 1a Start: 3M0PmMXVa8GG8dTw;
2016-11-21T13:46:15+00:00 DEBUG (7): AddAction: 1b Start: 3M0PmMXVa8GG8dTw;

2016-11-21T14:13:59+00:00 DEBUG (7): AddAction: 1a Start: 2VARZ8HVq3M4mjiV;
2016-11-21T14:13:59+00:00 DEBUG (7): AddAction: 1b Start: 2VARZ8HVq3M4mjiV;

All of them were correct additions to the cart.

We observed too that the PAGECACHE_FORMKEY cookie is present in every interaction, including the ones with the disabled module.

The PAGECACHE_FORMKEY is emited ever, including the extension disabled?

Thanks in advanced for you help.
It hope that helps.