[Qt-creator] Debugger hangs on breakpoint (near QSGRenderThread)

[Mateusz Loskot]

On 30 October 2013 19:19, André Pönitz
<andre.poenitz at mathematik.tu-chemnitz.de> wrote:
> On Tue, Oct 29, 2013 at 09:38:12PM +0000, Mateusz Loskot wrote:
>> Hi,
>>
>> I'm using Qt Creator 3.0.81 (Qt 5.2.0 64-bit) on Linux,
>
> [As a side note: 'master' is usually unattended between about
> a week before beta releases and the release candidate, it's
> really not recommended to use, even for 'bleeding edge' cases
> during that time]

The documentation [1] does not say which branch to build from,
so I thought it assumes the master as default, if one builds from Git.
The README [2] says "Check out Qt Creator (master branch"

[1] http://doc-snapshot.qt-project.org/qtcreator-extending/getting-and-building.html
[2] https://qt.gitorious.org/qt-creator/qt-creator/source/0ddb6cac29628425b7c2490a20df944f062ce50c:README

>> built on October 26 from the source code pulled
>> from the Git repository. It's debug/development build
>> and I'm using two separate copies of the build:
>> one to develop, the other to lauch and debug a plugin.
>>
>> While debugging some plugins and I've noticed that
>> the debugging session freezes once the execution
>> reaches some of breakpoints. It happens fairly often,
>> but I haven't noticed the exact pattern of what kind of
>> breakpoints actually make the debugger freeze.
>>
>> For example, I placed breakpoint in the CMakeProjectManager plugin's
>> CMakeBuildConfigurationFcatory::availaleBuilds() method, then
>> - the execution stops at it, then 1-5 seconds later
>> - the stacktrace refreshes view and displays completely unrelated,
>> - the step over/in/out buttons get disabled,
>> - the debugger is not responding on stepping,
>> - the only buttons that are active are pause and stop.
>>
>> Here are three screenshots to show what's going on during the sequence above:
>> http://imageshack.com/a/img577/6858/ccqe.png
>> http://imageshack.com/a/img5/5714/kdn7.png
>> http://imageshack.com/a/img850/5031/9wvl.png
>
> This pretty much looks like an unclean build.

What part of the build you suspect to be unclean, Qt or Qt Creator or
the plugin(s)?
I built Qt and Qt Creator only once.
Then, I built/rebuilt some of plugins (unchanged source code) more than once.

>> Interestingly, every time it happens, the view title bar
>> displays QSGRenderThread and "Running" next to it.
>>
>> If I hit the blue pause button, it changes to "Stop requested"
>> and eventually it shows "Attempting to interrupt" which hangs forever.
>>
>> The only thing I can do is to abort debugging and restart it.
>>
>> I noticed similar issue while debugging other plugins like the
>> GenericProjectManager
>> and others.
>>
>> I wonder, is this something known?
>> Do I need to tweak the Qt Creator/GDB debugger settings in some way?
>> Does it look like a bug and shall I report?
>
> I'd 'git clean -dxf ; qmake ; make' (for a checkout from 3.0 branch)
> and check whether the problem persists. If it does, file a bug and
> attach the debugger log (contents of the right pane of Windows->
> Views->Debugger)

Surely, I will try to do it and report back if the problem persists.

Thanks very much!

Best regards,
-- 
Mateusz  Loskot, http://mateusz.loskot.net