QSignalSpy crashed the test executable when testing a static lib.

CKurdu

While testing a static library, the test app crashed due to QSignalSpy.

Project structure.

test CMakeLists.txt

cmake_minimum_required(VERSION 3.16)
project(testsubject LANGUAGES CXX)

set(CMAKE_AUTOMOC ON)


find_package(Qt6 REQUIRED COMPONENTS Core Gui Test Widgets)

qt_add_executable(testsubject
    testsubject.cpp
)

set_target_properties(testsubject PROPERTIES
    WIN32_EXECUTABLE TRUE
    MACOSX_BUNDLE TRUE
)

target_link_libraries(testsubject PUBLIC
    Qt::Core
    Qt::Gui
    Qt::Test
    Qt::Widgets
    subject
)

testsubject.cpp

#include <QTest>
#include "subject.h"
#include <QSignalSpy>

class TestSubject: public QObject
{
    Q_OBJECT
    Subject* m_subject;
private slots:
    void name();
    void initTestCase()
    {
        m_subject = new Subject();
    }
};


void TestSubject::name()
{
    QSignalSpy spy(m_subject,&Subject::nameChanged);
    m_subject->setName("cafer");
    spy.wait();
    QCOMPARE(spy.count(),1);
}

QTEST_MAIN(TestSubject)
#include "testsubject.moc"

result

When I use subject source files without linking them statically adding directly, there are no problems.

The crash occurs when the spy object gets destroyed.

I'm unsure if this is a bug or I'm doing something incorrectly. Can you help me figure it out?

Christian Ehrlicher

As always - use a debugger to see where it crashes. And then simplify the application until it either no longer crashes or you found the bug. If it's small enough, post a minimal, compilable reproducer here.

CKurdu

Thank you for your quick response @Christian-Ehrlicher

This is already a minimal example and below is a GitHub repository show that.

https://github.com/ckurdu/staticlib_qttest

It's interesting that the same problem started happening when I added subject files directly, so I think I am making a mistake this is not a bug.

CKurdu

@Christian-Ehrlicher
The situation is turning strange because MinGW compiler works well with all styles, static or not.

CKurdu

The problem only occurs in debug mode.

When Qt Creator is in debug mode, the program crashes.

OMG, I spent four hours on this.

CKurdu

The problem occurs with below config

Qt 6 6 0 MSVC2019 64bit debug.
debug mode

Christian Ehrlicher

Then you somehow mix debug and release libraries which is not supported with MSVC.

CKurdu

@Christian-Ehrlicher
I think you are right. Because, on my other PC, there is no problem. I tried many things.
I removed the debug folder to try to start the config cmake project from scratch. It didn't work. Now I am reinstalling Qt 6.6.0

CKurdu

The problem was solved after I reinstalled Qt 6.6.0. However, I am still unsure of what caused the issue in the first place.

Thank You @Christian-Ehrlicher