Bug 448708

Description Maciej Bendkowski 2014-10-24 09:25:15 EDT

The command framework defines a "visibleWhen" function responsible for determining when a command is to be displayed. Unfortunately, this function has to be synchronous and therefore cannot be dependent on external communication, in particular installed plugins. Currently, to circumvent the related timing issues, we use the validationProperties which covers some trivial display triggers, i.e. presence or absence of certain properties of item objects. Unfortunately, the framework does not allow the use of universal or existence quantification, and thus is preventing from more advanced triggers. In my particular use-case, I need to quantify over the existence of a plugin which satisfies a certain predicate. I understand that the visibleWhen function can't be time-consuming in principle, but is *should* allow communication with plugins via a fast synchronous communication canal, e.g. by allowing to call plugin-provided functions.