[Qt-creator] Odd QtCreator hang

[André Pönitz]

On Tue, Apr 17, 2018 at 12:27:07PM +0000, Murphy, Sean wrote:
> > > I've got an odd hang with QtCreator when debugging my software.
> > Oh, as you are on Windows, that's the third platform that show
> > clipboard-related strage effects.
> > 
> > We already have QTCREATORBUG-20262 and QTBUG-67729. Can you please
> > check
> > these?
> 
> I had stumbled upon QTBUG-67729 yesterday when searching for this issue, and I 
> think I read this line from it differently than I am today: " We consistently get a hang 
> when we hit a breakpoint if we happen to copy text to the clipboard before we hit
> the breakpoint". I dismissed that as different than what I was doing, but this morning
> I think it might be essentially the same. What I was doing was setting a breakpoint 
> well above the QClipboard::setText() call (which is why I thought it wasn't quite the same),
> but then I was stepping one line at a time through my code including over that line,
> which I'm now guessing is effectively the same as setting a breakpoint after the copy.
> 
> I didn't find QTCREATORBUG-20262 yesterday, but I just built it and ran it as the reporter
> described. They didn't post the .pro file used, so I'm not sure if all of those build settings were
> the same. Anyways, when I ran it Qt Creator didn't lock up, but I did get the attached popup. If I 
> switch the QClipboard::setImage() call in his example to QClipboard::setText(), leaving the 
> breakpoint on the qDebug() line, Creator again doesn't hang, but it does drop into the 
> disassembler (relevant info pasted below).
> 
> I'm realizing that I neglected to mention that I am using the mingw toolchain on Windows,
> so maybe it's a gdb issue?
> 
> Call stack when disassembler hit
> 	1 ntdll!DbgBreakPoint                 0x7741000d 
> 	2 ntdll!DbgUiRemoteBreakin            0x7749f306 
> 	3 ??                                  0x6ac2b5ef 
> 	4 KERNEL32!BaseThreadInitThunk        0x76be343d 
> 	5 ntdll!RtlInitializeExceptionChain   0x77439832 
> 	6 ntdll!RtlInitializeExceptionChain   0x77439805 
> 	7 ??                                             

> 
> Disassembler
> 0x7741000c                   cc              int3
> 0x7741000d  <+0x0001>        c3              ret
> 0x7741000e  <+0x0002>        90              nop

There are other threads running at that time. The output of
'thread apply all backtrace full' would be interesting.

Perhaps even in JIRA.

Andre'