QTreeWidget causes the app to crash after deleting the last QTreeWidgetItem

[jsulm]

@Andrea_Venturelli It's not clear to me what debugger you set in the Kit you're using? Seems to be lldb. With MinGW one is usually using GDB. The GDB debugger is provided as part of the MinGW setup from Qt Online Installer.

[Andrea_Venturelli]

@jsulm let's see if this helps you a little bit more.

unfortunally i do not understand where I need to search for the informations needed to help you understand why my debugger fails to compile and run.

I'm open to suggestions or direction where to retrive this kind of helpfull information in order to simplify your life and not wasting so much of yours time.

[jsulm]

@Andrea_Venturelli Please check in the Kit you're using what debugger is set there. It should be GDB from MinGW.

[Andrea_Venturelli]

yes @jsulm, is GDB as illustrated in the code snippet some messages ago

this is taken from the "Global Debugger Log" panel , after running the Debug play button
and is clearly referring to GDB

• GDB PROCESS FINISHED, status 0, exit code 1 (0x1)
• d[GDB] NOTE: ENGINE SETUP FAILED

d[GDB] UNEXPECTED GDB STDERR: error: unknown option: --tty=\\.\pipe\creator-11944-28798
derror: unknown option: -i
dUse 'lldb.exe --help' for a complete list of options.
d[GDB] GDB PROCESS FINISHED, status 0, exit code 1 (0x1)
d[GDB] NOTE: ENGINE SETUP FAILED
d[GDB] State changed from EngineSetupRequested(1) to EngineSetupFailed(2)
<Debugging has failed.
d[GDB] State changed from EngineSetupFailed(2) to DebuggerFinished(16)

[jsulm]

@Andrea_Venturelli said in QTreeWidget causes the app to crash after deleting the last QTreeWidgetItem:

dUse 'lldb.exe --help' for a complete list of options.

Why don't you simply check in the Kit which debugger is set?

[Andrea_Venturelli]

how can i do that? it's not clear to me, where the informations of the debug type resides; a screenshot could be helpfull or even the path like so:

[Qt creator] >> Edit >> Preferences... >> Debugger .. and so on or
[Qt Maintenance Tool] >> Extencion >> ecc..

because I have a little experience with Qt Creator, resulting in me, not knowing where to look for

[jsulm]

@Andrea_Venturelli [Qt creator] >> Edit >> Preferences... >> Kits - then select the Kit you're using

[Andrea_Venturelli]

this is what I use to create the projects (and using qMake to built):

[jsulm]

@Andrea_Venturelli Please show ALL settings of that Kit (especially Qt version and debugger set).

[Andrea_Venturelli]

Desktop Qt 6.7.1 llvm-mingw 64-bit

c++ compiler:

LLVM-MinGW 17.0.6 64-bit for c++

Debugger:

LLVM lldb 17.0.6 64-bit

Qt version:

Qt 6.7.1 llvm-mingw 64-bit

CMake Tool:

CMake 3.27.7 (Qt)

[jsulm]

@Andrea_Venturelli Try with Qt for MinGW (not llvm-mingw).
Maybe QtCreator does not support lldb properly.

[cristian-adam]

It looks like the LLVM MInGW debugger has the wrong debugger type set. It should be LLDB and not GDB.

https://bugreports.qt.io/browse/QTBUG-123330 was supposed to be a thing of the past...

[Andrea_Venturelli]

How should I change the current project KIT, transitioning from llvm-mingw to MinGW ??

I tryed it, from the preferences panel under: Edit >> Preferences... >> Kits
but I'm pretty sure that has no impact on the current project, instead will change the default Kit, the next time I'll create a new project.

Exists such a way to change the Kit to the current running project or I'm forced to create a brand-new one and manually paste the code?

[jsulm]

@Andrea_Venturelli said in QTreeWidget causes the app to crash after deleting the last QTreeWidgetItem:

How should I change the current project KIT, transitioning from llvm-mingw to MinGW ??

On the right side in QtCreator "Projects".
From your screen-shots it looks like you already have a Kit for Qt MinGW.

[Andrea_Venturelli]

okay, finally we did it!
for the other reader who might encounter this problem with the debugger, the solution is:

1. on the left panel (where it is "Welcome", "Edit", "Design") there is "Projects"
2. open projects and under "Built & Run" you have all the kit available
3. I switched from Desktop Qt 6.7.1 llvm-mingw 64-bit to Desktop Qt 6.7.1 MinGW 64-bit
4. I pressed the "run" button and compile fine.
5. after I Run the normal "Debug play button" at the bottom left cornern and now is working

now we can go back to the main issues where this discussion started

[Andrea_Venturelli]

this is the error I get after deleting the last item in the QTreeWidget:

here the call stack:

I also found out where was the problem, other then I'm a big chicken ;)

SOLUTION

I had the QTreeWidget::ItemChanged signal, connected to one of my custom slots where i automatically update the values inside the LineEdits. But I ignored that, even when the last item is deleted, the QTreeWidget calls the "ItemChanged" signal.

adding a check if the, before trying to retrive information from an empty QTreeWidgetItem solved the problem

void Dialog::on_treeWidgetItemChanged()
{
    // check control
    if (m_paths.count())
    {
        auto current_itm = ui->left_wdg->currentItem();

        // update the lineEdit' values
        ui->fn_le->setText(current_itm->text(0));           // THIS WAS THE CAUSE OF THE ERROR
        ui->fPath_le->setText(current_itm->text(1));
    }
}