In a previous post I talked about using the QML Language Server for KDE development. Since writing that post a few things happened, so it’s time for an update.

I mentioned that when using Kate qmlls should work out of the box when opening a QML file. That’s mostly true, there is one problem though. Depending on your distribution the binary for qmlls has a different name. Sometimes it’s qmlls, sometimes qmlls6 or qmlls-qt6. You may need to adjust the LSP Server settings in Kate to match the name on your system.

In order for qmlls to find types that are defined in your application’s C++ code those must not only be declaratively registered, qmlls also needs to be told where to find the type information. Fortunately Qt 6.7 comes with a handy way to do that. By passing -DQT_QML_GENERATE_QMLLS_INI=ON to CMake you get an appropriate config file generated. This will be placed into the project’s source directory but is specific to your setup, so add that to your gitignore file (PS: You can set up a global gitignore file for your system, so you don’t need to add this to all your projects). Unfortunately the initial implementation produced wrong configurations for some modules, but this is fixed in Qt 6.7.2.

A problem I mentioned is that qmlls doesn’t find modules that are not installed into the same path as Qt. With Qt 6.8 there will be two new options. The -I parameter allows to add custom import paths to qmlls’ search paths. The -E parameter makes qmlls consider the value of the QML_IMPORT_PATH environment variable for its search paths.

In order for qmlls to work properly modules need to be created using the CMake API and use declarative type registration. Since writing the last post some KDE modules have been converted to those, but there’s still more to do.

Thanks to the QML team for those swift improvements!