Hi Nicolas,
I fixed this bug in MorphicTests-mt.77 by disabling "Morph haloForAll".
Well, I think that event handling in Morphic has a conceptual complexity that is comparable to other (non-Smalltalk) UI frameworks. Events travel through the hierarchy of morphs, starting in the world. Only one morph can be the actual handler. Event filters might intercept this, do something different, and tell the mechanism to further ignore the event.
In this test03EventHandler, the question was why that event did not reach its destination (here: that block in the test method). Of course, "self halt" does not work when a destination is not reached.
Why might an event not reach the desired handler (morph):
a) the target handler omits to reply to #handlesMouseDown: (etc.)
b) another (maybe sibling) morph is on top of it
c) the morph is not even in the hand's world
d) an event filter intervenes and marks the event as "ignored"
The cases a), b), and c) can easily be checked through the debugger. The world and the entire morph hierarchy is easily accessible. Bounds can be checked against the event's position.
This leaves case d), which is quite tricky to debug. Well, one can try to figure out, which implementor of #filterEvent:for: is the culprit. There are only 13 in the current Trunk. This path might lead to success. :-)
But I think we can do better. That's why I made it possible to log event-ignoring coming from arbitrary event filters in the hand (morph) we use in the event tests. The log includes short stacks to figure out the actual event filter. Here is an example for this bug:
While I did immediately recalled that "blue button fails" means "halo got the event" because I did something to the halo dispatcher in the last weeks, this is typically unclear for the average programmer, who is jumping between domains (and classes/packages) in the entire image. SO! By inspecting the "eventsIgnored" through the debugger, one can easily see both "mouseDown blue" and "PasteUpMorph >> tryInvokeHalo:" as the culprit.
That's why disabling the halo during this test solves the issue.
Best,
Marcel
Am 17.04.2021 13:43:08 schrieb Taeumel, Marcel <[hidden email]>:
My bad. I will take a look at it. Maybe I also find a way to improve documentation and code. I will keep you posted.
Marcel
From: Squeak-dev <[hidden email]> on behalf of Nicolas Cellier <[hidden email]>
Sent: Saturday, April 17, 2021 12:12:05 AM
To: The general-purpose Squeak developers list <[hidden email]>
Subject: [squeak-dev] I've reached my limits
I often recommend using the debugger in order to acquire a better
understanding of code.
A priori, I think that no bug can resist a thorough analysis/best efforts.
A posteriori, it seems that I've reached my limits with the debugging
of test03EventHandler.
If you find where the blue button down event is filtered/catched
without prior knowledge of Morphic event handling, by just stepping,
then either you are lucky, or your analytical capabilities are
tremendous (you can probably focus on 77 symbols simultaneously rather
than the average of 7)!
For me, that's not the right angle of attack!
All I acquired is an increased reluctance to start a deeper learning
of Morphic, more questioning about whether I'm becoming too old, and
the conviction that things are maybe getting too complex (more than
strictly necessary?).
Look at the full stack (which BTW is not the full stack -- and more
not shown --).
I let the test03EventHandler fix to people with prior knowledge, not
only because I was distracted by debugger bugs...
Nicolas
--- The full stack ---
MorphicEventTests(Object)>>halt
[] in MorphicEventTests>>test03EventHandler
EventHandler>>send:to:withEvent:fromMorph:
EventHandler>>mouseDown:fromMorph:
Morph>>mouseDown:
Morph>>handleMouseDown:
MouseButtonEvent>>sentTo:
Morph>>handleEvent:
MorphicEventDispatcher>>dispatchEvent:withHandler:withMorph:
[] in MorphicEventDispatcher>>dispatchMouseDown:with:
FullBlockClosure(BlockClosure)>>ensure:
MorphicEventDispatcher>>dispatchMouseDown:with:
MorphicEventDispatcher>>dispatchEvent:with:
Morph>>processEvent:using:
Morph>>processEvent:
[] in MorphicEventDispatcher>>dispatchEvent:toSubmorphsOf:
Array(SequenceableCollection)>>do:
PasteUpMorph(Morph)>>submorphsDo:
MorphicEventDispatcher>>dispatchEvent:toSubmorphsOf:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
MorphicEventDispatcher>>dispatchEvent:withHandler:withMorph:
[] in MorphicEventDispatcher>>dispatchMouseDown:with:
FullBlockClosure(BlockClosure)>>ensure:
MorphicEventDispatcher>>dispatchMouseDown:with:
MorphicEventDispatcher>>dispatchEvent:with:
PasteUpMorph(Morph)>>processEvent:using:
[] in PasteUpMorph>>processEvent:using:
[] in ActiveWorldVariable class(DynamicVariable class)>>value:during:
FullBlockClosure(BlockClosure)>>ensure:
ActiveWorldVariable class(DynamicVariable class)>>value:during:
[] in ActiveWorldVariable class>>value:during:
FullBlockClosure(BlockClosure)>>ensure:
ActiveWorldVariable class>>value:during:
PasteUpMorph>>becomeActiveDuring:
PasteUpMorph>>processEvent:using:
PasteUpMorph(Morph)>>processEvent:
HaloMorph(SimpleHaloMorph)>>mouseDown:
HaloMorph>>mouseDown:
HaloMorph(Morph)>>handleMouseDown:
MouseButtonEvent>>sentTo:
HaloMorph(Morph)>>handleEvent:
MorphicEventDispatcher>>dispatchEvent:withHandler:withMorph:
[] in MorphicEventDispatcher>>dispatchMouseDown:with:
FullBlockClosure(BlockClosure)>>ensure:
MorphicEventDispatcher>>dispatchMouseDown:with:
MorphicEventDispatcher>>dispatchEvent:with:
HaloMorph(Morph)>>processEvent:using:
MorphicEventDispatcher>>doProcessingForFocusEvent:with:
MorphicEventDispatcher>>dispatchFocusEventFully:with:
MorphicEventDispatcher>>dispatchFocusEventAllOver:with:
HaloMorph(SimpleHaloMorph)>>processFocusEvent:using:
HaloMorph(Morph)>>processFocusEvent:
[] in [] in [] in HandMorphForEventTests(HandMorph)>>sendFocusEvent:to:clear:
[] in ActiveEventVariable class(DynamicVariable class)>>value:during:
FullBlockClosure(BlockClosure)>>ensure:
ActiveEventVariable class(DynamicVariable class)>>value:during:
[] in ActiveEventVariable class>>value:during:
FullBlockClosure(BlockClosure)>>ensure:
ActiveEventVariable class>>value:during:
MouseButtonEvent(MorphicEvent)>>becomeActiveDuring:
[] in [] in HandMorphForEventTests(HandMorph)>>sendFocusEvent:to:clear:
[] in ActiveHandVariable class(DynamicVariable class)>>value:during:
-- and more not shown --
Locked
