Hi Christoph.

> However, currently, a #deprecated call in a drawing method makes the image unusable ...

Yes, there is a lot of room for improvement in Squeak's strategy to keep the image alive and in a recoverable state. Annoying things include errors in event handlers (such as #mouseOver:) and the thing about Warnings you mentioned for #displayWorldSafely.

Since the exception mechanism can be used to implement dynamic scope (see CurrentReadOnlySourceFiles), we should never catch Exception in general to install such handlers.

Warning might be a nice addition to #displayWorldSafely.

[Error] bench '219,000,000 per second. 4.57 nanoseconds per run.'

[Error, Halt] bench '11,900,000 per second. 84.4 nanoseconds per run.'

[Error, Halt, Warning] bench '9,910,000 per second. 101 nanoseconds per run.'

Since this is called only once to fourteen times per frame (see DamageRecorder) -- but usually only once -- we are good with 100 nanoseconds, given that 60 frames-per-second translate to 16 666 667 nanoseconds per frame.

Best,

Marcel

Am 25.10.2019 20:46:52 schrieb Thiede, Christoph <christoph.thiede@student.hpi.uni-potsdam.de>:

I see, but isn't it just their existence what we want to test for to prevent from loads of Debuggers appearing?

Or should we go the other way around and signal a "DebuggerRaisedNotification" each time before opening a debugger?

However, currently, a #deprecated call in a drawing method makes the image unusable ...

Von: Squeak-dev <squeak-dev-bounces@lists.squeakfoundation.org> im Auftrag von Taeumel, Marcel
Gesendet: Mittwoch, 23. Oktober 2019 15:48:15
An: John Pfersich via Squeak-dev
Betreff: Re: [squeak-dev] The Trunk: System-mt.1093.mcz

> Why isn't it sufficient to test for UnhandledError instead? Otherwise, we would also need to test for Warning etc. ...

UnhandledError and UnhandledWarning are (private) implementation details of Squeak's exception handling mechanism. They should never be exposed to (or used by) applications/frameworks.

Best,

Marcel

Am 22.10.2019 18:50:59 schrieb Thiede, Christoph <christoph.thiede@student.hpi.uni-potsdam.de>:

Why isn't it sufficient to test for UnhandledError instead? Otherwise, we would also need to test for Warning etc. ...

Von: Squeak-dev <squeak-dev-bounces@lists.squeakfoundation.org> im Auftrag von Taeumel, Marcel
Gesendet: Dienstag, 15. Oktober 2019 13:18:26
An: gettimothy via Squeak-dev
Betreff: Re: [squeak-dev] The Trunk: System-mt.1093.mcz

Yeah, I wonder whether we should expand "Error" to "Error, Halt"?

Best,

Marcel

Am 15.10.2019 12:45:42 schrieb Balázs Kósi <rebmekop@gmail.com>:

Hi Hannes!

This morning I've just run into this exact same situation: putting a halt into a method, called by a morph's #drawOn:

makes the image unusable.

The problem stems from WorldState >> displayWorldSafely: being safe only for Errors and not for other kind of

Exceptions, and Halt being only an Exception not an Error.

For a quick fix add Halt to the handled exceptions in #displayWorldSafely:

[aWorld displayWorld. finished := true] on: Error, Halt do: [:ex |

Balázs