If you think you have found a bug in Qt, we would like to hear about it so that we can fix it.
Before reporting a bug, please check the FAQs, Platform and Compiler Notes, and the Qt Bug Tracker on the Qt website to see if the issue is already known.
The first thing you should do is to sign up for an account for the Qt Bug Tracker, if you do not already have one. Once you have done that you can submit and track your bug reports and they will be publicly available from the moment you submit them.
Always include the following information in your bug report:
If possible, please provide a test written using the QtTest module as this will improve the procedure of reproducing your problem and allow the developers to address the issue in a more efficient way.
Otherwise, if the problem you are reporting is only visible at run-time, try to create a small test program that shows the problem when run. Often, such a program can be created with some minor changes to one of the many example programs in Qt's examples directory.
If you have implemented a bug fix and want to contribute your fix directly, then you can do so through the Public Qt Repository.