Problem reading session file

[sengaigibon]

I'm getting a weird behavior using Magento 2.0.2, it's described here as steps:

1. On 'Sign in' front page, as customer if I type a wrong username/password I get redirected to the same page (normal) but Magento doesn't display any error message (abnormal), I was expecting "Invalid login or password" from LoginPost.php . Taking a look to the proper session file in var/session/sess_###, the error is stored there...
2. I login again with the correct password and get redirected to my dashboard (normal) but the customer's name doesn't appear in the top menu bar, as a part of the welcome message (abnormal). Also, if the customer had in his car items from a previuos session, the orange square to the right of the cart icon doesn't show any amount.
3. Then, if I add any item to the cart I get the message 'You added xxx to your shopping cart' (normal) but not only this but also I get the previous 'Invalid login' message (abnormal).
4. After this, if I click on the cart icon and 'Go to Checkout' button, I get the login popup (abnormal) instead of going to the onepage checkout (normal).
5. Finally, if at this point I go back to 'My Account', I get the proper customer name in the top bar, with the proper amount of items in the cart and I can go to checkout as if nothing had happened.

I'm working on customize Magento for specific needs, I added a field to customer_entity table, 'mobile' field which has the same attributes as 'email' field. I disabled email as requiered field in the database. I added three custom fields stored in customer_entity_varchar. I had preferences of many files of Magento/Customer module. Even if I disable all my modules, rollback all my commits, clearing cache, var/generation, var/session and puc/static/frontend/*, I'm still getting this behavior. I have two instances, one running in production mode and one as developer, both has the same behavior.
I'm using Opera, Firefox and Chrome for the tests, clearing the browser history and cache makes no difference.

Also, I get this messages in the system.log file:

[2016-02-29 07:05:45] main.INFO: Cache file with merged layout: LAYOUT_frontend_STORE1_2c7461af04bb11fe209659d7147d2c579: Please correct the XML data and try again. [] []
[2016-02-29 07:05:45] main.INFO: Cache file with merged layout: LAYOUT_frontend_STORE1_20a98983867a1770682b48d9a0ad63441: Please correct the XML data and try again. [] []
[2016-02-29 07:05:45] main.CRITICAL: Broken reference: the 'catalog.compare.sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2016-02-29 07:05:45] main.CRITICAL: Broken reference: the 'sale.reorder.sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2016-02-29 07:05:45] main.CRITICAL: Broken reference: the 'wishlist_sidebar' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2016-02-29 07:05:45] main.CRITICAL: Broken reference: the 'paypal.partner.right.logo' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2016-02-29 07:05:45] main.CRITICAL: Broken reference: the 'bml.right.logo' element cannot be added as child to 'sidebar.additional', because the latter doesn't exist [] []
[2016-02-29 07:05:45] main.CRITICAL: Broken reference: the 'store.settings.currency' tries to reorder itself towards 'store_language', but their parents are different: 'store.settings' and 'header.panel' respectively. [] []
[2016-02-29 07:05:45] main.INFO: Cache file with merged layout: LAYOUT_frontend_STORE1_26f1b068ec7ccf4878f9284dd1137afd1: Please correct the XML data and try again. [] []

Sometimes, for an unknown reason the error disappear and the users can login and go to checkout normally. But this error is getting more persistent since 5 days ago.

Any advice to fix it? Thank you so much!

EDIT:
I must add something I read from a different issue: I also see the red/orange square next to the cart icon but empty, before and after login, only shows an amount after add something to the cart and adds this new item to those added in previous sessions.

UPDATE:

• For the error messages, on 'Sign in' frontpage, I realize that the object 'messages' inside "Magento/Theme/view/frontend/web/js/view/messages.js" is not getting populated.
• For the step (3) after adding a product, there is a call to "http://my.magento2.server/index.php/customer/section/load/?sections=compare-products%2Ccustomer%2Cwishlist%2Clast-ordered-items&update_section_id=false" which renders back the products in the cart and also the messages stored in the session file. I think is because it triggers the event listener "$(document).on('ajaxComplete', function (event, xhr, settings) " inside "Magento/Customer/view/frontend/web/js/customer-data.js" which update the content of the sections with the result of previous call to "section/load/?..." .
• For step (5), customer data comes from a call to "$(document).on('ajaxComplete', function (event, xhr, settings)". I saw this function is called on every section, but don't understand why on 'Sign in' page and after login it retrieves empty objects.

After step (5) take place, every access to magento site (e.g. in the browser, if I close the tab and reopen it from index.php or any other section of the store) is rendering correctly the customer name on top bar and items in the cart.

[pantaoran]

I also see this behavior, and it's really worrying me because as long as this persists I cannot possibly put any site live!

[devhn]

Same issues here and only after upgrading from 2.0.0. to 2.0.2.

[sevos1984]

@bb8d clearing cookies should be performed after upgrading. @sengaigibon there are two internal tickets that should solve your problem and will be delivered soon (MAGETWO-46014 and MAGETWO-49449)

[devhn]

@sevos1984 cookies and local storage was cleaned.

[sengaigibon]

Now I noticed two more issues, one is kind of the opposite of this one: I'm adding custom fields to the address, then in the checkout step 1, after I update the page pressing F5 suddenly I see a page telling me I have no items in my cart, customer name in the top menu bar, item amount in the orange square. If I click into My Account I get redirected to Sign in page... Should I open a new issue describing all the details?
The other thing I saw is after update the page in checkout step 1, the country in my already stored addresses disappear, and reappear after I cleaned var/session/*, browser cookies and log in again.

[sengaigibon]

@sevos1984 Great! Thanks! 👍

[sevos1984]

@sengaigibon Check that your system permissions set correctly http://devdocs.magento.com/guides/v2.0/install-gde/prereq/file-system-perms.html, also try clearing everything in var folder.

[sengaigibon]

I found that if I clean var/session* but don't clean browser cookies is when I get the behavior of the last comment with the customer name in the bar but logged out.

[pantaoran]

@sevos1984 what is the status on those MAGETWO-46014 and MAGETWO-49449? Also, will this lead to a new release or will I need to use the dev branch to get it fixed?
Or maybe I should direct this question to @slavvka since it was assigned to him?

[pantaoran]

Another week has gone by, so I'm going to ask again: Is this fixed now @sevos1984 and @slavvka ?
On the develop branch I see some commits regarding MAGETWO-49449, but MAGETWO-46014 is never mentioned so far.

We'd really like to show Magento2 in client meetings, but as long as a simple customer login doesn't work properly we just can't do that.

[sengaigibon]

@bb8d can you share with us some details about your installation environment? such as operating system, running a virtual machine or containers? any special software running on your Magento instance? Thanks!