Wednesday, June 24, 2020

Re: StyleInjector chokes on startup

I'm willing to provide more info, but TBH I'm not sure what are you asking.

You can see below code example that shows the problem. One "solution" that
triggers scheduleFinally to run is to invoke another scheduleFixedDelay -
that event is for sure not related to widgets, but I'm not sure if it is
related to JsInterop.

OTOH, I can confirm that handling mouse click on button widget DO triggers
scheduleFinally, too.

Like I've said, I've noticed new Sheduler (gwt-core) and all the differences
that it brings when compared to "old" Scheduler (gwt-client), but I didn't
test this new Scheduler.

So, "old" Scheduler obviously has a bug or at least very unexpected
behaviour. I agree that fixing this is not worth an effort if it's not a
very simple fix (which I assume it isn't), but I offered to document this
misbehaviour in form of bug report so that anyone else can at least find
this workaround if needed (I didn't found any reference to it so far).


On 24. 06. 2020. 19:16, Colin Alworth wrote:
> Can you clarify the browser event that you are working with? If it is
> something through JsInterop, then this is expected, since JSNI style calls
> into Java from JS require $entry, but jsinterop provides no such mechanism.
> If it is an event from a GWT Widget, then that would go through JSNI, and
> this should not happen.
>
> As such, https://github.com/gwtproject/gwt-core has an updated Scheduler
> which is compatible with JsInterop calls - scheduleFinally is now
> implemented as a microtask, so that it will always precede any subsequent
> event, no matter how the event originates. The gwt-core project also
> contains an updated StyleInjector, and a corresponding gwt-resources module
> (not yet moved to github.com/gwtproject) will provide an updated
> ClientBundle implementation.
>
> Note that as we're committed to maintaining legacy dev mode in the GWT 2.x
> branch, we cannot replace the com.google.gwt.core.client.Scheduler wiring
> with jsinterop.
>
> On Sunday, June 21, 2020 at 6:13:54 AM UTC-5, Gordan Krešić wrote:
>
> I'll take the blame for code design, no questions about that :)
>
> Do you think it's worth filing a bug report or this is too much of an edge
> case in a code that is going away soon anyway? Note that I didn't test
> against org.gwtproject.core.client.Scheduler only
> com.google.gwt.core.client.Scheduler (and they do differ, at least
> regarding
> scheduleFinally).
>
>
> On 19. 06. 2020. 09:42, Thomas Broyer wrote:
> > Yes, we can probably consider that a bug in GWT.
> > I'd also call this pattern of doing real work in a static initializer
> a code
> > smell:
> >
> http://misko.hevery.com/code-reviewers-guide/flaw-constructor-does-real-work/
> <http://misko.hevery.com/code-reviewers-guide/flaw-constructor-does-real-work/>
>
> > While still a flaw considering the above link, it's however a common
> > practice to call `ensureInjected()` from the class constructor (ideally,
> > you'd rather call it in a lifecycle method, such as Activity#start, or
> > Widget#onAttach); and that would likely fix your issue here.
> >
> > On Thursday, June 18, 2020 at 8:33:06 PM UTC+2, Gordan Krešić wrote:
> >
> >     On 18. 06. 2020. 20:25, Gordan Krešić wrote:
> >      > Probably unrelated with StyleInjector but with
> Scheduler.scheduleFinally
> >
> >     Ok, I've put a most basic repro case to prove that this is a
> Scheduler
> >     issue:
> >
> >     public class Foo {
> >
> >              static {
> >                      Scheduler.get().scheduleFinally(() ->
> >     GWT.log("Finally!"));
> >              }
> >
> >     }
> >
> >     Now initialite Foo on startup (in EntryPoint.onModuleLoad() for
> example),
> >     but "Finally!" will be printed only *after* first event loop, like
> >     described:
> >
> >     Scheduler.get().scheduleFixedDelay(() -> {
> >              return false;
> >     }, 0);
> >
> >              -gkresic.
> >
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