Get Involved/development/Set up a development environment

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Revision as of 13:55, 8 January 2024 by Ashark (talk | contribs) (→‎Set up Qt: Dependencies should be handled by kdesrc-build itself. No need to make different lists in different places.)

Information

Everything on this page only needs to be done once. Once you've done it, your development environment is set up and you can use it to submit patches and develop KDE Software!


Note

This procedure will set up kdesrc-build for Qt6 and KDE Frameworks 6.
Setting up kdesrc-build for Qt5 and KDE Frameworks 5 is an advanced topic.


Source code for KDE software lives on KDE Invent. But before you can work on it, you'll need to set up a development environment: a set of tools that allows you to access and edit the source code, compile it into a form that the computer can run, and deploy it to a safe location. We will now go through the process of setting one up. To accomplish these tasks, you will need to enter commands using a terminal program, such as KDE's Konsole.

If you're not familiar with the command line interface, you can find tutorials here. However, advanced command-line skills are not required, and you will learn what you need along the way!

If you're a visual learner, we also provide video tutorials about setting up kdesrc-build.

Install basic tools

First you will need to use your operating system's package manager to install some basic tools:

  • KDE Neon/Kubuntu/Ubuntu/Debian: sudo apt update && sudo apt install git
  • Arch/Manjaro: sudo pacman -S git
  • Fedora: sudo dnf install git perl perl-IPC-Cmd perl-MD5 perl-FindBin
  • openSUSE Tumbleweed: sudo zypper refresh && sudo zypper install git

Configure Git

We need to set your authorship information properly so that any changes you make can be properly attributed to you: 

git config --global user.name "Your Name"
git config --global user.email "[email protected]"

The name you provide should be your actual name, not your KDE Identity username or a pseudonym. And the email address must be the same as the email address used for your https://bugs.kde.org account. If they don't match, then the BUG: and FEATURE: keywords won't work (see this page for more information).

Next, in order to authenticate yourself when pushing code changes, you need to add an ssh key to your GitLab profile as described here.

Set up kdesrc-build

kdesrc-build is the official KDE meta-build-system tool. It is used to manage the building of many software repositories in an automated fashion. Its primary purpose is to manage dependencies. Every software has dependencies: other pieces of software that provide lower-level functionality they rely on. In order to compile any piece of software, its dependencies must be available.

KDE software has two types of dependencies: dependencies on other pieces of KDE software, and dependencies on 3rd-party software. For example, the KDE application KCalc depends on more than 20 other KDE git repositories as well as the Qt toolkit.

Some Linux distributions do not provide development packages for KDE Frameworks and of other libraries that are up-to-date enough for us to build from the "main" branch of the KDE git repositories (the branch where the development of the next software versions takes place), so we use kdesrc-build to compile them ourselves. The goal is to avoid using KDE binaries, KDE libraries and other KDE files from the operating system where possible (in the Linux case, these files reside in the /usr directory).

Let's set it up now! First, create a new directory for all the KDE source code. You will need many gigabytes of free disk space. Budget 50 GB for KDE Frameworks + KDE Plasma, and 10-30 GB more for some apps as well. Then clone the kdesrc-build git repository in that directory: 

mkdir -p ~/kde/src
cd ~/kde/src/
git clone https://invent.kde.org/sdk/kdesrc-build.git && cd kdesrc-build

Next, some distros need source repos enabled before you can install the development packages you need. Do that now, if needed:

  • KDE neon/Debian/Ubuntu/Kubuntu/etc: sudo sed -i '/^# deb-src/s/^# //' /etc/apt/sources.list && sudo apt update. Look at the content of the file /etc/apt/sources.list, e.g. cat /etc/apt/sources.list. Each line that starts with "deb " should be followed by an identical line but the line should start with "deb-src ", e.g.:
deb http://us.archive.ubuntu.com/ubuntu/ noble main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ noble main restricted
  • openSUSE Tumbleweed: sudo zypper mr -e $(zypper repos | awk '/source/{print $5}')

With that done, it's time to run the initial setup program, which will make some changes to your ~/.bashrc (or ~/.zshrc for zsh users) and install the necessary binary packages from your Linux operating system: 

./kdesrc-build --initial-setup
source ~/.bashrc

The step ./kdesrc-build --initial-setup above installs the Linux binary packages that are needed such that kdesrc-build can build all of KDE Frameworks.

Note

If you use zsh and you selected yes for auto-completions during kdesrc-build --initial-setup, add the following two lines to ~/.zshrc if these two lines are not already there: 
autoload -U +X compinit && compinit
autoload -U +X bashcompinit && bashcompinit

If you use fish but only have it set up as an interactive shell (instead of a login shell set with chsh), in order for kdesrc-build to ask you whether you want to update fish, you will need to run initial setup while setting the SHELL environment variable to fish manually instead: 

SHELL=fish ./kdesrc-build --initial-setup


For more details about installing the needed Linux binary packages, see Get_Involved/development/Install_the_dependencies

Handling dependencies after setup

The kdesrc-build --initial-setup command invokes kdesrc-build --install-distro-packages as one of the steps. It installs 3rd-party dependencies once run. But they can change over time, and kdesrc-build is currently not smart enough to track those changes and apply them later; see https://invent.kde.org/sdk/kdesrc-build/-/issues/9 for more details.

So after setup, if you want to ensure you do not miss some 3rd party dependency do the following:

  • Update kdesrc-build itself: kdesrc-build kdesrc-build. This will update your ~/kde/src/kdesrc-build/data/pkg/*.ini, which lists the required dependencies.
  • Invoke installation command again: kdesrc-build --install-distro-packages.

If you still find any external dependencies needed to build KDE software that were not installed with kdesrc-build --install-distro-packages, then please send a merge request to the kdesrc-build repository to include the needed packages in the list.

Set up Qt

Qt is the fundamental framework that is needed for pretty much all KDE development. A recent enough version of Qt 6, currently Qt version greater or equal to 6.6, is required to proceed.

The initial setup of kdesrc-build should have installed the required Qt6 packages for you already.

If your Linux distribution does not provide recent versions of qt packages, it may be a good time to switch distros to something better suited for building KDE software from source code either as the primary operating system or in a virtual machine. Building Qt6 using kdesrc-build or installing Qt6 using the Qt online installer are advanced topics.

Disable indexing for your development environment

You'll want to disable indexing for your development-related git repos and the files they will build and install. Add the directory ~/kde to the exclusions list in System Settings > Workspace > Search > File Search, like so:

Next Steps

Reboot your computer and log back in so the package changes, and the ~/.bashrc changes take effect on your user account. Once that's done, your development environment is set up and ready to build software. Time to learn how to use kdesrc-build tool to build software from source code!

Start compiling KDE software using kdesrc-build

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