Mini panels can load the wrong context from page manager, causing an EntityMalformedException

Problem/Motivation

Mini panels can use the context of the active page manager page.

Depending on how the block render call is invoked, the wrong type of entity context can be loaded, for example a taxonomy term can be loaded as a node.

This will cause a panels mini block to be rendered even though a required context does not exist.

In certain circumstances it can also cause an EntityMalformedException in entity_extract_ids() in /includes/common.inc , for example when a ctools access plugin checks for a value on a node field, against a taxonomy context.

panels_min_block_list_alter() prevents this from happening when the blocks are added to regions via the core block system. It checks that the page manager contexts match the required mini panel contexts, if they don’t it removes the block from the list of renderable blocks.

However other modules that render the block may not invoke this alter hook, for example the context module.

Steps to reproduce (on a default install):

1.Download and enable context, panels, page manager and mini panels
2.Create a mini panel with a required context “node”.
3. Create a pane in the mini panel with some custom text.
4. Add a visibility rule to the pane that checks the value of a field on the node, eg the body field.
5. Save the mini panel (example mini panel export attached).
6. In page manager, enable the ‘taxonomy/term’ page.
7. In context, create a new context
8. Add a path condition ‘taxonomy*’
9. Add a block reaction adding the mini panel you created above to a region. (example context attached)
10. Create a term in an existing taxonomy (you may need to create a vocab first).
11. View the term you have created. You will get an EntityMalformedException error.

Proposed resolution

1.Move the requirements matching check from panels_mini_block_list_alter() to a stand alone function, panels_mini_match_requirements().
2.Check for requirements via panels_mini_match_requirements() from both panels_mini_block_list_alter() and panels_mini_block_view().

Patch to follow.

Remaining tasks

Reviews needed.

User interface changes

In some production sites, mini panels that should not appear because a required context is not present might currently appear. Applying this patch would cause those mini panels to disappear.