Capability overview loading same context data repeatedly

The capability overview improvements implemented by MDL-40368 introduced a recursive function call in the renderer. This recursive call to 'capability_comparison_table()' is called once for each context. Each call in turn calls the tool_capability_calculate_role_data() function using the exact same parameters as the callee. This behaviour results in slow page loading which can potentially lead to timeouts when a large result sets are generated (usually when there are lots of overrides and/or capabilities selected).

One proposed solution to address this involves adding a static variable to capability_comparison_table() which will cache the return data from tool_capability_calculate_role_data() for each different capability / context combination.

I will link a change with this proposed solution in this tracker shortly.