QT_NO_DEBUG_OUTPUT not effective until clean build

asked 2020-03-22 22:39:35 +0200

Direc
5243 ●104 ●149 ●149

Hi,

I have scratching my head - again - over QT_NO_DEBUG_OUTPUT, and finally I managed to pin it down. Here are the steps to reproduce the problem with Sailfish Application SDK 3.0.7:

• Create new project
• Add #include <QDebug> in main.cpp
• Add qDebug() << "Debug messages enabled"; to main() function
• Set the app run in release mode in Sailfish emulator and click the "play" button to run it
• Note that the line is printed, as expected, and close the application
• Add line DEFINES += QT_NO_DEBUG_OUTPUT to the project file
• Save the file, Qt Creator disables and enables the "play" button as the changed project file is processed
• Click the "play" to run the application again
• Note that the line is still printed, despite the DEFINE, and close the application
• Select Build > Clean project "name" from the menu
• Click the "play" to run the application again
• Note that the line is no longer printed, as expected

Other way to test this is to wrap qInfo() inside #ifdef QT_NO_DEBUG_OUTPUT block, and it too requires cleaning the project before the project files becomes effective.

Now, if instead of QT_NO_DEBUG_OUTPUT I use a custom string, say NO_BLAH instead, no clean build is required in order for the #ifdef block to be effective.

So, it looks to me that QT_NO_DEBUG_OUTPUT is handled differently and something fishy is going on in that front. I think this qualifies as a bug.

Thanks!

PS. Clean build doesn't solve this question, hence this new question.