How to patch Qt

The Qt repository is split into submudules, so pushing a fix for it is not very trivial. Let's assume you have Krita deps built using Krita's build scripts and you want to modify Qt and push a fix into the registry.

1. Make a commit in QtBase submodule

   When using submodules, the submodule folder is in "detached" state without any branch assigned, so we need to reset the branch head after we make a commit:

   cd qtbase
   git commit -a -m "your commit message"
   
   # reset the branch head (make sure you don't have any local
   # changes in 'krita/5.15' branch!)
   
   git update-ref refs/heads/krita/5.15 HEAD
   git checkout krita/5.15
   git pull --rebase
   
   cd ..
   

2. Make a commit in the root repository and push

   git checkout krita/5.15
   git pull --rebase
   git commit -a -m "commit message for the root repo"
   git push --recurse-submodules=on-demand
   

3. Update the sha1-link in Krita's repository

   1. Open 3rdparty/ext_qt/CMakeLists.txt

   2. Modify QT_GIT_TAG with the newly pushed sha1

   3. Push!