[Lazarus] Recovering from unhandled exceptions

[Michael Van Canneyt]

On Thu, 15 Oct 2009, Mattias Gaertner wrote:

> On Thu, 15 Oct 2009 09:09:27 +0200 (CEST)
> Michael Van Canneyt <michael at freepascal.org> wrote:
>
>>
>>
>> On Wed, 14 Oct 2009, Hans-Peter Diettrich wrote:
>>
>>> Recently I stumbled into a situation where an unhandled exception
>>> gave me the choice to either kill Lazarus, or to continue at my own
>>> risk. Pressing the wrong shortcut key can be fatal in this
>>> situation :-(
>>>
>>> IMO such a dialog, with severe consequences, should not use
>>> standard OK/Cancel buttons, and also should not associate commonly
>>> used shortcuts with the buttons. Instead more intuitive
>>> Kill/Continue buttons should be used.
>>>
>>> In typical situations the Escape key is associated with Cancel,
>>> meaning to abort or undo a wrong action. In the case of an
>>> exception this should mean to cancel the *action* (and continue),
>>> not to kill the *application*.
>>
>> I think that this is a good proposal.
>> The QuestionDLG can be used for this, I assume.
>
> The MessageBox is used, because it can be handled completely
> by the widgetset and therefore works even if the heap got corrupted.
>
> It is a matter of priority. Show some information to help fixing the
> bug, or help the user to ignore the bug.

For a fact, the user usually cannot make this decision :-)

>
> We could:
> Add a flag to Application so that the programmer can decide what to
> show (MessageBox/QuestionDlg).
> And/Or: add an event to let the programmer show its own dialog.

This latter exists already, no ? OnShowException ?

Michael.