Qt5Core.dll dependencies to parent folder

TL;DR

Qt5Core.dll expects:

../lib/Qt5Core.lib

../qml/QtQuick/Controls.2/qmldir

../qml/QtQuick/Controls.2/qtquickcontrols2plugin.dll

../qml/QtQuick/Templates.2/qmldir

../qml/QtQuick/Templates.2/qtquicktemplates2plugin.dll

../qml/QtQuick/Window.2/qmldir

../qml/QtQuick/Window.2/windowplugin.dll

../qml/QtQuick.2/qmldir

../qml/QtQuick.2/qtquick2plugin.dll

Verbose:

I have a few console apps and a single QML app bundled together in the same folder. Running windeployqt for each and pointing it to the QML where applicable, I create a distributable folder package.

When run, the QML app seems to start and stop immediately. No errors displayed. The console apps work fine.

Tracking down differences between the setup in my build folders and the distributable folder package I discovered deleting Qt5Core.dll made the QML app start correctly. When missing, the dll was picked up from C:\Qt\5.15.0\msvc2019_64. Further digging revealed that Qt5Core.dll seems to reference dependencies outside the folder. Putting lib and qml folders from C:\Qt\5.15.0\msvc2019_64 next to the package folder, the QML app started correctly with Qt5Core.dll in place.

Finally narrowing it down, the lib folder must contain Qt5Core.lib. The qml folder must contain the folders QtQuick/Controls.2, QtQuick/Templates.2, QtQuick/Window.2, QtQuick.2 and they must all contain qmldir and release dll files. Removing either the lib file or one qmldir or dll, the QML app no longer starts.

I guess these dependencies in turn depend on the QML in use.