[Qt6] Cannot normally quit the main application window

[Kazzz-S]

Previously, I thought the problem captured in the attached video was macOS-specific.
However, I have found that it is also reproducible on Linux.
So I could collect the valgrind output.

1. OS and Compiler

• OS: Linux Mint 20.3 Una 64 bits

MyHost{sekigawa}(1)$ uname -a
Linux MyHost 5.4.0-170-generic #188-Ubuntu SMP Wed Jan 10 09:51:01 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

• Compiler: LLVM/Clang++ built from source

MyHost{sekigawa}(2)$ clang++ --version
clang version 17.0.6 (https://github.com/llvm/llvm-project.git 6009708b4367171ccdbf4b5905cb6a803753fe18)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin

• Built 96df10b by expert mode
• This problem does not occur in the combination of (96df10b & Qt5.12.8 & g++ 9.4.0) on the same Linux.

2. Qt

• Qt 6.6.1 built from source (qt-everywhere-src-6.6.1.tar.xz) using the above clang++

MyHost{sekigawa}(3)$ pwd
/usr/local/Qt-6.6.1/bin

MyHost{sekigawa}(4)$ ./qmake --version
QMake version 3.1
Using Qt version 6.6.1 in /usr/local/Qt-6.6.1/lib

---

• Video

case-04.mp4

• valgrind --leak-check=full --show-leak-kinds=all --track-origins=yes -s
  case-04-valgrind_output.zip

[klayoutmatthias]

Hi @Kazzz-S,

I tried myself on Ubuntu 22.04 with on-board Qt 6.2.1 and I see normal behavior. I built without Qt bindings for now, but I will try with. I also have Qt 6.4.2 and will try this one too.

Matthias

[stefanottili]

On MacOS M1 klayout hangs on exit without qt-bindings.
Compiled with homebrew qt6 which is currently using qt 6.6.1

[klayoutmatthias]

No luck with Ubuntu 22 and Qt 6.4.2 that comes with Qt Creator :(

@Kazzz-S I noticed one thing in the video above: when you open the layout it appears to take a while to load. A progress bar should be displayed while it does so. On the other hand your layout isn't large, so what is happening during that time?

There are more things to test:

1.) Maybe some popup is showing which can't be dismissed? I had such issues when starting KLayout and some tip dialogs appeared on screens that were not active.I tried to make dialogs appear on the same screen than the main application where possible and I have no clue what dialog could appear. There is one about saving the layout, but that's all. A simple check may be to try in viewer mode (there should not be any save needed) or to try without a layout loaded. Does the problem happen in that case too?

2.) Any useful output on the terminal when you run KLayout with verbose logging on, i.e. "-d 31" or even "-d 41", like "klayout -d 41"?

3.) There are some other ways to exit unconditionally:

• Macro editor console: Ruby mode - command: exit!
• Macro editor console: Ruby mode - command: RBA::Application.instance.exit(0)

Does one of these methods work?

4.) Potentially the problem is located somewhere in the MainWindow::can_close method in layMainWindow.cc, line 1409. This function can veto against closing the window by returning false. You could put in some printf statements to find out whether or why it would return false or do trial-and-error by putting in return true statements at strategic places to see where is a the reason for failing to return true.

If you put a return true right at the beginning like this:

bool
MainWindow::can_close ()
{
  return true;
...
}

the program should exit in any case but also without any warnings. If it does not, the problem is not inside this function.

Matthias

[Kazzz-S]

Hello @klayoutmatthias,

@Kazzz-S I noticed one thing in the video above: when you open the layout it appears to take a while to load. A progress bar should be displayed while it does so. On the other hand your layout isn't large, so what is happening during that time?

I think the time it took to load the design was because I was running KLayout (debug build) under the hood of valgrind.
The design is so small that the progress bar would not appear in a normal run.

The small window size was intentional to keep the size of the captured video file small.

I'll try all the suggested tests and get back to you.

Regards,
Kazzz-S

[klayoutmatthias]

Thanks, I'm curious what will be the outcome :)

Matthias

[Kazzz-S]

@klayoutmatthias, I've conducted the four experiments. I'll show the results one by one.

• I used a debug build in the following tests. To begin with, about...

0. About

about.mp4

[Kazzz-S]

Test-1. Read-Only mode

#!/bin/bash
#--------------------------------------------------------------------
# File: gh1602-test1.sh
#
# Description: Startup script for testing the cases suggested in
#              https://github.com/KLayout/klayout/issues/1602
#
# Test-1: Read-Only mode
#--------------------------------------------------------------------
SCRIPT_DIR=$(cd $(dirname $(readlink -f $0 || echo $0));pwd -P)

KLAYOUT_LIBS=$SCRIPT_DIR
KLAYOUT_EXE=$SCRIPT_DIR/klayout
RLATED_LIBS=/usr/local/lib

export LD_LIBRARY_PATH=$KLAYOUT_LIBS:$RLATED_LIBS:$LD_LIBRARY_PATH
eval "$KLAYOUT_EXE -style=fusion -ne $*"

(a) File -> Exit

test1-.a.FileExit.mp4

(b) Window's Close [X]

test1-.b.WinCloseX.mp4

---

1.) Maybe some popup is showing which can't be dismissed? I had such issues when starting KLayout and some tip dialogs appeared on screens that were not active.

I cannot see such a popup or dialog.

[Kazzz-S]

Test-2. -d 41 option

#!/bin/bash
#--------------------------------------------------------------------
# File: gh1602-test2.sh
#
# Description: Startup script for testing the cases suggested in
#              https://github.com/KLayout/klayout/issues/1602
#
# Test-2: "-d 41" option
#--------------------------------------------------------------------
SCRIPT_DIR=$(cd $(dirname $(readlink -f $0 || echo $0));pwd -P)

KLAYOUT_LIBS=$SCRIPT_DIR
KLAYOUT_EXE=$SCRIPT_DIR/klayout
RLATED_LIBS=/usr/local/lib

export LD_LIBRARY_PATH=$KLAYOUT_LIBS:$RLATED_LIBS:$LD_LIBRARY_PATH
eval "$KLAYOUT_EXE -style=fusion -d 41 $* > ./gh1602-test2.log 2>&1"

(a) File -> Exit

test2-.a.FileExit.mp4

gh1602-test2-(a).zip

(b) Window's Close [X]

test2-.b.WinCloseX.mp4

gh1602-test2-(b).zip

---

There are many Warnings in the output log file.

Warning: Class QJsonArray_Iterator: no Python mapping for method ->
Warning: Class QJsonObject_Iterator: no Python mapping for method ->
Warning: Class QMetaObject_SuperData: no Python mapping for method ->
Warning: Class QRandomGenerator: no Python mapping for method (reserved word) global
Warning: Class QRandomGenerator64: no Python mapping for method (reserved word) global
Warning: Class QDrag_Native: no Python mapping for method (reserved word) exec
Warning: Class QDrag_Native: no Python mapping for method (reserved word) exec
Warning: Class QPageSetupDialog_Native: no Python mapping for method (reserved word) exec
Warning: Class QSqlDatabase: no Python mapping for method (reserved word) exec
Warning: Class QSqlResult: no Python mapping for method (reserved word) exec
Warning: Class Edges: no Python mapping for method (reserved word) and
Warning: Class Edges: no Python mapping for method (reserved word) and
Warning: Class Edges: no Python mapping for method (reserved word) not
Warning: Class Edges: no Python mapping for method (reserved word) not
Warning: Class Edges: no Python mapping for method (reserved word) or
Warning: Class Edges: no Python mapping for method (reserved word) in
Warning: Class Region: no Python mapping for method (reserved word) and
Warning: Class Region: no Python mapping for method (reserved word) not
Warning: Class Region: no Python mapping for method (reserved word) or
Warning: Class Region: no Python mapping for method (reserved word) in
Warning: Class Region: no Python mapping for method (reserved word) break
Warning: Class QCoreApplication_Native: no Python mapping for method (reserved word) exec
Warning: Class QEventLoop_Native: no Python mapping for method (reserved word) exec
Warning: Class QThread: no Python mapping for method (reserved word) exec
Warning: Class QGuiApplication_Native: no Python mapping for method (reserved word) exec
Warning: Class QTextDocument_Native: no Python mapping for method (reserved word) print
Warning: Class QWindow_Native: no Python mapping for method (reserved word) raise
Warning: Class QApplication_Native: no Python mapping for method (reserved word) exec
Warning: Class QWidget_Native: no Python mapping for method (reserved word) raise
Warning: Class QPrintPreviewWidget_Native: no Python mapping for method (reserved word) print
Warning: Class QSqlQuery: no Python mapping for method (reserved word) exec
Warning: Class QSqlQuery: no Python mapping for method (reserved word) exec
Warning: Class Application: no Python mapping for method (reserved word) exec
Warning: Class QDialog_Native: no Python mapping for method (reserved word) exec
Warning: Class QDialog: no Python mapping for method (reserved word) exec
Warning: Class QErrorMessage: no Python mapping for method (reserved word) exec
Warning: Class QFileDialog: no Python mapping for method (reserved word) exec
Warning: Class QFontDialog: no Python mapping for method (reserved word) exec
Warning: Class QInputDialog: no Python mapping for method (reserved word) exec
Warning: Class QLineEdit_Native: no Python mapping for method (reserved word) del
Warning: Class QMenu_Native: no Python mapping for method (reserved word) exec
Warning: Class QMenu_Native: no Python mapping for method (reserved word) exec
Warning: Class QMenu_Native: no Python mapping for method (reserved word) exec
Warning: Class QMessageBox: no Python mapping for method (reserved word) exec
Warning: Class QProgressDialog: no Python mapping for method (reserved word) exec
Warning: Class QWizard: no Python mapping for method (reserved word) exec
Warning: Class QAbstractPrintDialog: no Python mapping for method (reserved word) exec
Warning: Class QPrintDialog_Native: no Python mapping for method (reserved word) exec
Warning: Class QPrintDialog: no Python mapping for method (reserved word) exec
Warning: Class QPrintPreviewDialog: no Python mapping for method (reserved word) exec
Warning: Class BrowserDialog: no Python mapping for method (reserved word) exec
Warning: Class QColorDialog: no Python mapping for method (reserved word) exec
Warning: Class QPlainTextEdit_Native: no Python mapping for method (reserved word) print
Warning: Class QTextEdit_Native: no Python mapping for method (reserved word) print
Warning: The X11 connection broke (error 1). Did the X11 server die?

[Kazzz-S]

Test-3. Using the macro editor console

#!/bin/bash
#--------------------------------------------------------------------
# File: gh1602-test3.sh
#
# Description: Startup script for testing the cases suggested in
#              https://github.com/KLayout/klayout/issues/1602
#
# Test-3: Using the macro editor console
#--------------------------------------------------------------------
SCRIPT_DIR=$(cd $(dirname $(readlink -f $0 || echo $0));pwd -P)

KLAYOUT_LIBS=$SCRIPT_DIR
KLAYOUT_EXE=$SCRIPT_DIR/klayout
RLATED_LIBS=/usr/local/lib

export LD_LIBRARY_PATH=$KLAYOUT_LIBS:$RLATED_LIBS:$LD_LIBRARY_PATH
eval "$KLAYOUT_EXE -style=fusion $*"

(a) exit!

test3-.a.exit.mp4

(b) RBA::Application.instance.exit(0)

test3-.b.exit.0.mp4

[Kazzz-S]

Test-4. Code Changes

• Patch File ===> 0001-gh1602-debug.zip

[Kazzz-S]

Test-4A. Without force return

#!/bin/bash
#--------------------------------------------------------------------
# File: gh1602-test4A.sh
#
# Description: Startup script for testing the cases suggested in
#              https://github.com/KLayout/klayout/issues/1602
#
# Test-4: With debug codes added to "layMainWindow.cc"
#         A) 'MAGIC_FORCE_TRUE' env. variable unset
#--------------------------------------------------------------------
SCRIPT_DIR=$(cd $(dirname $(readlink -f $0 || echo $0));pwd -P)

KLAYOUT_LIBS=$SCRIPT_DIR
KLAYOUT_EXE=$SCRIPT_DIR/klayout
RLATED_LIBS=/usr/local/lib

export LD_LIBRARY_PATH=$KLAYOUT_LIBS:$RLATED_LIBS:$LD_LIBRARY_PATH

unset MAGIC_FORCE_TRUE
eval "$KLAYOUT_EXE -style=fusion $*  > ./gh1602-test4A.log 2>&1"

(a) File -> Exit

test-4A.a.FileExit.mp4

In MainWindow::can_close:: 1) Application seems not to be busy
In MainWindow::can_close:: 2) Plugins seem to be ready to exit
In MainWindow::can_close:: 3) No need to save a layout
In MainWindow::can_close:: 1) Application seems not to be busy
In MainWindow::can_close:: 2) Plugins seem to be ready to exit
In MainWindow::can_close:: 3) No need to save a layout

(b) Window's Close [X]

test-4A.b.WinCloseX.mp4

In MainWindow::can_close:: 1) Application seems not to be busy
In MainWindow::can_close:: 2) Plugins seem to be ready to exit
In MainWindow::can_close:: 3) No need to save a layout

[Kazzz-S]

Test-4B. With force return

#!/bin/bash
#--------------------------------------------------------------------
# File: gh1602-test4B.sh
#
# Description: Startup script for testing the cases suggested in
#              https://github.com/KLayout/klayout/issues/1602
#
# Test-4: With debug codes added to "layMainWindow.cc"
#         B) 'MAGIC_FORCE_TRUE' env. variable set
#--------------------------------------------------------------------
SCRIPT_DIR=$(cd $(dirname $(readlink -f $0 || echo $0));pwd -P)

KLAYOUT_LIBS=$SCRIPT_DIR
KLAYOUT_EXE=$SCRIPT_DIR/klayout
RLATED_LIBS=/usr/local/lib

export LD_LIBRARY_PATH=$KLAYOUT_LIBS:$RLATED_LIBS:$LD_LIBRARY_PATH

export MAGIC_FORCE_TRUE="CAN_CLOSE_MAINWINDOW"
eval "$KLAYOUT_EXE -style=fusion $*  > ./gh1602-test4B.log 2>&1"

(a) File -> Exit

test-4B.a.FileExit.mp4

In MainWindow::can_close:: 0) Forcibly return 'true'
In MainWindow::can_close:: 0) Forcibly return 'true'

(b) Window's Close [X]

test-4B.b.WinCloseX.mp4

In MainWindow::can_close:: 0) Forcibly return 'true'

[Kazzz-S]

It looks like the problem is NOT inside MainWindow::can_close ()!

[klayoutmatthias]

Hi @Kazzz-S,

thanks a lot for these experiments.

I now got Qt 6.6.1 myself and tried to reproduce the issue on Ubuntu, without success. The application simply closes.

I conclude, that can_close is called which means some other problem is present.

The warnings from the log file just say that some methods are renamed because their names are reserved words in Python. That is normal. The log does not indicate any issues.

I have some more things I can suggest to try:

"can_close" is actually called from inside MainWindow::exit. This method is found in layMainWindow.cc, line 1365++:

  //  Only after other operation has finished we ask whether to save and close eventually
  if (can_close ()) {

    do_close ();
    QMainWindow::close ();

    emit closed ();

  } else {
    m_exited = false;
  }

I would try to check whether the code gets to these places (1) to (4):

  if (can_close ()) {

    //  (1)
    do_close ();
    //  (2)
    QMainWindow::close ();

    //  (3)
    emit closed ();
    //  (4)

  } else {
    m_exited = false;
  }

Even though there is no return statement, some methods may raise an exception for some reason which could prevent the method from closing the window.

If that happens, for example if (1) is reached, but (2) isn't, the exception can be captured to reveal the reason, like this:

  if (can_close ()) {

    //  (1)
    BEGIN_PROTECTED
      do_close ();
    END_PROTECTED
    //  (2)
    QMainWindow::close ();

    //  (3)
    emit closed ();
    //  (4)

  } else {
    m_exited = false;
  }

"BEGIN_PROTECTED" and "END_PROTECTED" are macros that insert try .. catch statements and print the error before continuing.

I'm sorry for this kind of remote debugging, but I wish I could reproduce the problem on my side.

Best regards,

Matthias