Added a check in Mailbox preRemove hook call. If the hook is returnin…

[mfechner]

…g a false, stop the deletion of the mailbox. The plugin has to add a message why the deletion of the mailbox was canceled.

This change is required to further implement pull request #179

[mfechner]

I documented the hook mailbox_purge_preRemove on the wiki page which was missing completely.

[barryo]

I'm not sure I like the idea of plugins being able to prevent deletion. Have we done this anywhere else?

My issue is if we have >1 plugin and the other plugins do their pre-deletion work on the assumption it'll succeed, then your plugin cancels the deletion, we'll have a potentially inconsistent state.

The answer may be just to document this and for plugins that do irreversible pre-deletion tasks to use the preFlush or postFlush hook.

Can you add some documentation to the call covering the above and - also - reverse the styling changes you made? Styling should be consistent to the rest of the file. Thanks a million.

[mfechner]

yes, the alias deletion has the same logic in. That is how I understood the hooks, pre is there to do checks before the action is executed and post after the action as executed, please correct me if I understood there something wrong. Therefor I see it very logic that a pre check should be able to stop the action if required.

I updated the wiki.

Sorry for the style change, me IDE is doing it automatically, I reverted it.

[mfechner]

I add a new part to the hook documentation:
https://github.com/opensolutions/ViMbAdmin/wiki/Plugins#workflow-of-actions-in-hooks

Hopefully that describes it a little better. Suggestions are welcome ;)

[barryo]

Cheers @idefix6 - merging now.