Respect 'node_permissions_[content type]' variable settings

Problem/Motivation

From function comment for node_permissions_get_configured_types()

By default, this will include all node types in the system. To exclude a specific node from getting permissions defined for it, set the node_permissions_$type variable to 0. Core does not provide an interface for doing so. However, contrib modules may exclude their own nodes in hook_install(). Alternatively, contrib modules may configure all node types at once, or decide to apply some other hook_node_access() implementation to some or all node types.

Right now 'content_access' module assumes that the default node permissions will be always available. It is possible for another module to disable those available permissions by doing something like,

variable_set('node_permissions_' . $content_type, 0);

where $content_type can be 'article', 'page', etc...

And when content_access tries to use the missing permission, Drupal throws errors similar to below,

Notice: Undefined index: edit any article content in user_role_grant_permissions() (line 3163 of /var/www/html/cm7/modules/user/user.module). =>

This is because the core doesn't expose the permission 'edit any article content' if variable 'node_permissions_article' is set to '0'.

Proposed resolution

Solution 1

Ignore all the content type where default core permission have been overriden (i.e. where node_permissions_[content type] is set to 0).
Show a message to the user about the situation and prompt the user to revert the settings so that content_access can work with those content types.

Solution 2

In case the core permissions are missing for a particular content type, declare them. This can lead to confusion in the future when the permission become available again in the system though.

Solution 3

Declare incompatibility with modules that disables core permissions. This will need no code change in content_access module.