Hooks for customizing behavior on system errors

[brp-benjamin]

If there is an exception thrown by a custom component the system will treat that as an unrecoverable error and it will be handled internally by the SystemErrorHandler class. The SystemErrorHandler will create a client side element which informs the end user that they need to refresh the ui.

We wish to customize this element as well as add server side logic that logs unrecoverable errors to our helpdesk system. However as far as I can see there is no ability to hook into the SystemErrorHandler.

[Artur-]

Is this the same as #801 which causes exceptions to go to ErrorHandler in VaadinSession instead of always causing an "Internal Error"? This you can customize using VaadinSession.setErrorHandler

[brp-benjamin]

I'm not sure I understand your comment. SystemErrorHandler is a different from ErrorHandler, while we can set a custom ErrorHandler for logging etc this does not allow us to control the SystemErrorHandler and the element that SystemErrorHandler creates in the browser.

[Artur-]

Depends on if you are talking about a client or a server side exception.

For server side exceptions, they would be routed to the same SystemErrorHandler where you can add UI components, show a notification or do whatever you want. Currently the framework always sends these as "internal errors" to the client side, where they then end up in SystemErrorHandler without any information about what actually went wrong.

For client side exceptions you would need something else, on the client side.

[Artur-]

It is possible to replace SystemErrorHandler with your own implementation but that involves extending and recompiling flow-client. Not sure if that is even documented anywhere

[estronque]

Is there any other mechanism to prevent the div from being displayed even if I am in development mode?

Analyzing the code of version 2.7.13 I see that if "registry.getApplicationConfiguration().isProductionMode()" is true the div is not displayed.

I understand that creating a 'custom flow client' maven project could make the project unstable.