Re: [hatari-devel] Big bug in the SDL UI

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 24/06/2015 09:24, Nicolas Pomarède a écrit :
> as stated above, this is random ; my change should require a reset, so
> the confirmation dialog not showing depending on where I clicked in the
> "Prefetch mode, slower" text is a bug.

Here's how I can reproduce it on every try ; it looks random at first, 
but in fact it's because it depends on the X location of the mouse when 
clicking "Prefetch mode, slower"

- compile hatari with winuae cpu (to have more options in the system dialog)
- remove hatari.cfg so that hatari will start with its default values
- run for example : hatari --tos tos404.img --machine falcon
- press F12, go into system dialog
- default is that "prefetch mode" is selected
- click on the "c" in the text "prefetch mode", this will disable 
prefetch mode
- now, without moving the mouse, press "enter"
- you go back to the main menu, notice that since the mouse was above 
the "c" of "prefetch mode", it is now above the "no reset" object
- press "enter" again to exit main menu

- we go back to emulation, but there was no "you need to reset" dialog

repeat above steps, but click on the "p" of "prefetch mode" to disable 
it, press "enter" twice and now the dialog "you need to reset" should 
appear.

From what I see, the problem happens when the system dialog is closed 
and we redraw the main menu.

At this point if the mouse corresponds to a valid object's area in the 
main menu (in that case it's object id=16 "No Reset") then if we click 
on "OK" or press enter, the main menu will keep "16" as the object that 
was selected, instead of returning 0. So current_object becomes 16.
Then the main menu call the dialog for "you need to reset", but as 
current_object is >0 (ie 16) when this dialog is called, this is 
interpreted as if the user canceled, without even drawing the dialog.

This will do this part of the if in SDLGui_DoDialog
        if (current_object >= 0 && dlg[current_object].type == 
SGSCROLLBAR) {
          ...
        }

But current_object refers to an object in main menu, while dlg not 
refers to the new dialog menu we want to draw (the "you need to reset" 
dialog), so this doesn't make sense.

So I wonder, why does current_object keeps its value between different 
dialogs ? From what I see, it should be set to 0 (or -1) when a new 
dialog opens in SDLGui_DoDialog(), is there a case where we want 
current_object to be propagated between different dialog as it is now ?

Nicolas