By joining the ranks of KDE developers, you will get to implement new features and defeat bugs both daunting and simple, all while collaborating to make coherent and stable releases. Developers collaborate in teams based on what area they are working in. These can be small teams working on a single application, up to large teams working on a group of related pieces of software. Many developers are in more than one team.
By joining the ranks of KDE developers, you will get to implement new features and defeat bugs both daunting and simple. Developers collaborate in teams based on what area they are working on. These can be small teams working on a single application, up to large teams working on a group of related pieces of software, or even meta-teams working on broader topics such as QA or automation. Many developers participate in more than one team.
KDE runs or participates in several mentoring programs to help new developers, including an informal list of people who are willing to help newcomers get started. See the [[Mentoring]] page for more details.
KDE runs or participates in several mentoring programs to help new developers, including an informal list of people who are willing to help newcomers get started. See the [[Mentoring]] page for more details.
== Requirements ==
== Where to find the development team ==
=== Prerequisite skills ===
Most KDE software is written in C++ using the [https://www.qt.io Qt toolkit] and [https://develop.kde.org/products/frameworks/ KDE Frameworks]. Though prior experience with these technologies or other programming languages is helpful, you don't need to be a C++ programmer to get started! For example, no programming knowledge whatsoever is required to do things like improve text labels.
The KDE developers are here to assist you if you need any help following this guide.
If you'd like to dive deeper, the Qt wiki contains [https://wiki.qt.io/Books a list of online books] for learning Qt programming. Qt also provides [https://doc.qt.io/qt-5/qtexamplesandtutorials.html lots of examples] you can look at. For visual learners, [https://www.youtube.com/watch?v=JxyTkXLbcV4&list=PL6CJYn40gN6hdNC1IGQZfVI707dh9DPRc this YouTube playlist of QML tutorials] by KDE patron [https://www.kdab.com KDAB] may be useful. Finally, information about KDE Frameworks can be found on the [https://develop.kde.org/docs KDE Developer Platform] and [https://api.kde.org/ KDE API website].
There are several ways to get in touch with KDE developers, either generally or for a specific project. The most important communication channels are:
* '''Real-time chat:''' [irc://irc.libera.chat/kde-devel #kde-devel] room on the [http://libera.chat/ Libera Chat] IRC network (which is mirrored to the [https://webchat.kde.org/#/room/#kde-devel:kde.org #kde-devel] room on [[Matrix]])
* '''Forum:''' [https://discuss.kde.org/c/development/10 Development forum] on discuss.kde.org
* '''Mailing list:''' [https://mail.kde.org/mailman/listinfo/kde-devel kde-devel] ([http://kde.org/support/#mailinglists Learn more about mailing lists])
These are general KDE development communication channels, and you may be directed to a more appropriate place for the project you're interested in.
=== Operating system ===
* Many projects and teams have their own real-time chat channels, which can be found on the [[Matrix#Rooms|Matrix Rooms]] page.
* There is a [http://www.kde.org/mailinglists/ list of mailing lists] if you want to find a mailing list for a specific team directly.
We recommend that you set up the development environment (kdesrc-build) on a Linux operating system installed on your laptop or computer or on a Linux operating system installed in a virtual machine.
The [[Main Page]] of this wiki includes links to specific development teams and the [[Get Involved]] page includes links to more general contribution teams.
Support for Windows and macOS is still experimental and you may have a better experience [[/Developing in a virtual machine|doing your development in a virtual machine using a Linux distribution]].
== Prerequisites ==
==== Linux ====
=== Skills ===
The Linux distribution should provide relatively recent versions of Qt and KDE Frameworks.
Most KDE software is written in C++ using the [https://www.qt.io Qt toolkit] and [https://develop.kde.org/products/frameworks/ KDE Frameworks]. Though prior experience with these technologies or other programming languages is helpful, you don't need to be a C++ programmer to get started! For example, no programming knowledge whatsoever is required to do things like improving text labels.
Linux distributions that are better suited for kdesrc-build are rolling-release Linux distributions (Arch, openSUSE Tumbleweed, KDE neon) or the latest version of Fedora KDE Spin or Kubuntu.
If you'd like to dive deeper, the Qt wiki contains [https://wiki.qt.io/Books a list of online books] for learning Qt programming. Qt also provides [https://doc.qt.io/qt-5/qtexamplesandtutorials.html lots of examples] you can look at. For visual learners, [https://www.youtube.com/watch?v=JxyTkXLbcV4&list=PL6CJYn40gN6hdNC1IGQZfVI707dh9DPRc this YouTube playlist of QML tutorials] by KDE patron [https://www.kdab.com KDAB] may be useful. Finally, information about KDE Frameworks can be found on the [https://develop.kde.org/docs KDE Developer Platform] and [https://api.kde.org/ KDE API website]. We also provide a [[Get_Involved/development/Learn|wiki page full of learning resources]].
{{Note|While you can still build KDE software using kdesrc-build on other Linux distributions or FreeBSD, you may have a better experience [[/Developing_in_a_virtual_machine|doing your development in a virtual machine using one of the Linux distributions mentioned above]].}}
=== Operating system ===
==== Microsoft Windows, Apple macOS, FreeBSD ====
Setting up a development environment on [[/More#Other_operating_systems|Microsoft Windows, Apple macOS or FreeBSD]] is an advanced topic.
=== Integrated Development Environment (IDE) ===
While it is not required to edit code, it is recommended to set up [[Get_Involved/development/IDE_configuration|graphical development tools or an Integrated Development Environment (IDE)]]. You may want to try out [http://www.kdevelop.org KDevelop], the KDE IDE.
== Setting up the development environment ==
{{Info|'''Everything in this section 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 Qt5 and KDE Frameworks 5.<br/>
Setting up kdesrc-build for Qt6 and KDE Frameworks 6 and setting up kdesrc-build inside a Docker container are [[Get_Involved/development/More|advanced topics]].}}
Source code for KDE software lives on [https://invent.kde.org 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 [https://konsole.kde.org/ Konsole] (but any terminal program will suffice).
If you're not familiar with the command line interface, you can [https://lifehacker.com/5633909/who-needs-a-mouse-learn-to-use-the-command-line-for-almost-anything find a reasonable tutorial here]. However, advanced command-line skills are not required, and you will learn what you need along the way!
=== Video version ===
If you are a visual learner, you might consider watching the video version at https://www.youtube.com/embed/B4xoc0K5iA4
[[Get_Involved/development/Video|More video versions]].
=== Install basic tools ===
<pre class="ml-0 pre-input" style="display: inline;">Set up kdesrc-build - Step 1/6.</pre>
First you will need to use your operating system's package manager to install some basic tools:
* KDE Neon/Kubuntu/Ubuntu/Debian: <code>sudo apt install git cmake dialog</code>
{{Note|The name you provide should be your actual name, not your KDE Identity username.
<nowiki>
</nowiki>
The email address you specify above must be the same as the email address used for your https://bugs.kde.org account. If they don't match, then the <code>BUG: </code> and <code>FEATURE: </code> keywords won't work (see [https://techbase.kde.org/Development/Git/Configuration#Basic_Settings this page] for more information).}}
<br />
In order to authenticate yourself when pushing code changes, you need to add an ssh key to your GitLab profile as [https://invent.kde.org/help/user/ssh.md described here].
=== Set up kdesrc-build ===
<pre class="ml-0 pre-input" style="display: inline;">Set up kdesrc-build - Step 2/6.</pre>
Next, we need a method of '''managing dependencies'''. Every software has dependencies: other pieces of software that provide the functionality they rely on. In order to compile any piece of software, its dependencies must be available.
E.g. the KDE application kcalc depends on more than 20 other KDE git repositories: KDE Frameworks and other KDE libraries.
Most Linux operating systems do not provide development packages of the KDE Frameworks 5 and of other KDE libraries that are up-to-date enough. We will not be able to build from the "master" branch of the KDE git repositories.
Therefore we will compile all of the KDE git repositories ourselves, including KDE Frameworks 5 and other KDE libraries. We should not use KDE files (binaries, libraries and other files) from the OS (i.e. the /usr directory). To do this, we use a command-line tool called <code>kdesrc-build</code> to download, manage, build, and install KDE git repositories. Let's set it up now!
First, we create a new directory for all the KDE source code we will be using. You will need many GB of free disk space. Budget 50 GB for KDE Frameworks + KDE Plasma, and 10-30 more for some apps as well. We then clone the <code>kdesrc-build</code> git repository in that directory.
{{Input|1=<nowiki>
# If you have an old installation of kdesrc-build and you want a clean kdesrc-build installation, run a command line like: # mv ~/.config/kdesrc-buildrc ~/.config/kdesrc-buildrc~bak ; mv ~/kde ~/kde~bak
mkdir -p ~/kde/src
cd ~/kde/src/
git clone https://invent.kde.org/sdk/kdesrc-build.git && cd kdesrc-build
</nowiki>}}
Next, it's time to set up <code>kdesrc-build</code> and pick up the changes it made to your <code>~/.bashrc</code> (or <code>~/.zshrc</code> for zsh users) for the current terminal session:
{{Input|1=<nowiki>
# For supported operating systems (OSes), it installs all of the OS packages needed in order to build all of the KDE Frameworks 5.
./kdesrc-build --initial-setup
source ~/.bashrc
# Check that the command line above has worked by seeing if the PATH environment variable contains "~/kde/src/kdesrc-build".
echo $PATH
</nowiki>}}
{{Warning|Do not run the command <code>kdesrc-build</code> without any arguments because this will build everything, which is probably overkill right now.}}
{{Note|If you use zsh and selected yes for auto-completions during the initial setup for <code>kdesrc-build</code>, add the following to <code>~/.zshrc</code> if it is not already there.
{{Input|1=<nowiki>
autoload -U +X compinit && compinit
autoload -U +X bashcompinit && bashcompinit
</nowiki>}}
}}
The initial setup creates the kdesrc-build configuration file <code>~/.config/kdesrc-buildrc</code>.
{{Warning|Make sure that the file <code>~/.config/kdesrc-buildrc</code>, after the line <code>global</code>, contains the line <code>branch-group kf5-qt5</code>.}}
Run <code>kdesrc-build --help</code> for the kdesrc-build command line help.
=== Set up Qt ===
Qt is the fundamental framework that is needed for pretty much all KDE development. We need a recent enough version of Qt to proceed. If you are just getting started, we recommend that you [[Get_Involved/development#Linux|use a Linux distribution that is better suited for kdesrc-build]] either as the primary operating system or in a virtual machine.
You can look up the version of the Qt framework installed on your operating system by opening the application "Info Center" (KInfoCenter) > Basic Information > About this System > "Qt Version:". Or starting any installed KDE application (e.g. the KDE calculator app (kcalc)) and from the application's main menu > Help > About ''application'' > Components tab > "Qt".
If you have Qt 5.15 or any later version installed, you are already done with the "Set up Qt" step and can proceed to the next section. 🎉
...otherwise we now need to install a more recent version from somewhere. Your distribution might have one available. Alternatively, we need to configure <code>kdesrc-build</code> to build and install a recent Qt version for you. [[Get_Involved/development/More#Build_Qt_using_kdesrc-build|Building Qt using kdesrc-build]] is a more advanced topic.
=== Disable indexing for your development environment (optional) ===
You'll want to disable indexing for your development-related git repos and the files they will build and install. Add <tt>~/kde</tt> to the exclusions list in System Settings > File Search, like so:
[[File:Getting involved development file index options.png|center|600px|]]
=== Download non-KDE dependencies ===
<pre class="ml-0 pre-input" style="display: inline;">Set up kdesrc-build - Step 3/6.</pre>
If your distribution is supported, <code>kdesrc-build --initial-setup</code> will install the distribution packages which are needed in order to build KDE software. <code>kdesrc-build</code> is used in order to build any of the KDE git repositories. The packages for Qt and the rest of the dependencies are acquired using your Linux distribution's package manager.
Please [[/Install_the_dependencies|install at least all of the dependencies needed in order to build all of the KDE Frameworks. Steps 4 and 5 of setting up kdesrc-build are here]].
'''Reboot your computer''' and log back in so the package changes, and the changed ~/.bashrc take effect on your user account.
Once that's done, your development environment is set up and ready to build software! Let's take it for a spin.
{{Note|If you happen to find an external dependency needed to build KDE software that was not installed with <code>kdesrc-build --initial-setup</code>, once you finish this tutorial, you may send a merge request to https://invent.kde.org/sdk/kdesrc-build/-/blob/master/modules/ksb/FirstRun.pm in order to include the respective distro package to the list.}}
== Building software with kdesrc-build ==
It can take an hour or more to compile a KDE application, Framework, or Plasma itself for the first time. The reason for this is that <code>kdesrc-build</code> is compiling all of the KDE Frameworks 5 modules plus any other KDE module that is a dependency of the module that you tell <code>kdesrc-build</code> to build.
<code>kdesrc-build</code> by default has the option "--include-dependencies" enabled so it will ignore all KDE packages that were installed using the distribution's package manager and will instead build all needed KDE modules from source.
The next time you want to compile that or any other piece of KDE software, it will be much faster since most of the dependencies will have already been compiled. If you don't want to build all dependencies (e.g., because you are using a rolling release distro that provides recent versions of software), edit the same configuration file and simply set <code>include-dependencies</code> to '''false''' or add the <code>--no-include-dependencies</code> option when running <code>kdesrc-build</code>.
=== KDE Frameworks ===
<pre class="ml-0 pre-input" style="display: inline;">Set up kdesrc-build - Step 6/6.</pre>
'''[[Frameworks|KDE Frameworks]]''' are libraries of tools and features that can be used by any application or Plasma itself. New versions of KDE Frameworks are [[Schedules/Frameworks|released once a month]]. A list of all of the frameworks can be found here: https://api.kde.org/frameworks.
After you [[Guidelines and HOWTOs/Build from source/Install_the_dependencies#For_all_of_the_KDE_Frameworks_5|install all of the dependencies needed in order to build all of the KDE Frameworks]], the first thing that you should do using <code>kdesrc-build</code> is to build all of the KDE Frameworks:
Note: if you cannot build the KDE Framework kdewebkit because your Linux OS does not have the qtwebkit package, that is not a problem.
If a KDE Framework fails to build, see [[#Most_important_current_build_issues|the list of the most important current kdesrc-build build issues]].
=== Applications ===
[https://apps.kde.org/ KDE Applications] like [https://apps.kde.org/kcalc Calculator (KCalc)], [https://apps.kde.org/dolphin/ Dolphin], [https://apps.kde.org/okular/ Okular], [https://apps.kde.org/konsole/ Konsole] and [https://apps.kde.org/gwenview/ Gwenview] are standalone apps that can be run on multiple platforms, such as Plasma, GNOME, even macOS and Windows! New versions of KDE Applications are [[Schedules#Current_Releases_by_KDE|released three times a year]]. Note that the Discover app store (git repo name: <code>plasma-discover</code>) and System Settings app (git repo name: <code>systemsettings</code>) are distributed alongside Plasma, but they build like apps using the below instructions. A list of all KDE applications can be found here: https://apps.kde.org/.
The general steps required to build and run an application are described in the following using kcalc as an example:
{{Input|1=<nowiki>
For KDE development, we recommend a Linux operating system installed on your computer or in a [[/Developing_in_a_virtual_machine|virtual machine]]. The ones best suited for development provide relatively recent versions of libraries needed by KDE software, and use the "[https://en.wikipedia.org/wiki/Rolling_release rolling release]" model. Some examples are Arch Linux, openSUSE Tumbleweed, and KDE neon. The latest version of Fedora KDE usually works as well.
kdesrc-build kcalc
</nowiki>}}
This will also build all of the KDE git repositories on which kcalc depends such as e.g. KDE Frameworks 5 libraries.
We recommend that you use the KDE Plasma desktop on your Linux operating system.
The command line above has cloned the KDE git repository https://invent.kde.org/utilities/kcalc in the directory <code>~/kde/src/kcalc</code>. Has built kcalc in the directory <code>~/kde/build/kcalc</code>. And has installed kcalc in the directory <code>~/kde/usr</code>.
As a part of this process, the <code>kcalc</code> executable was installed to <code>~/kde/usr/bin/kcalc</code>. '''There is no need to manually install anything;''' <code>kdesrc-build</code> installed it for you! Source the project's auto-generated <code>prefix.sh</code> file every time you want to run your custom-compiled version of kcalc:
Support for Windows and macOS are still experimental, and you may have a better experience [[/Developing in a virtual machine|doing your development in a virtual machine using a Linux distribution]]. Setting up a development environment on [[/More#Other_operating_systems|other operating systems--including FreeBSD]]--is an advanced topic.
{{Input|1=<nowiki>
== The main way to develop KDE software: kdesrc-build ==
source ~/kde/build/kcalc/prefix.sh
kcalc
# You can check that "/home/username/kde/usr/bin" is the first directory in $PATH.
# echo $PATH
</nowiki>}}
Or using the <code>kdesrc-run</code> command:
KDE uses a custom tool called '''kdesrc-build''' for setting up a development environment and building KDE software. You only need to set up your environment once, and then you can compile (and recompile) KDE software as often as needed.
{{Input|1=<nowiki>
kdesrc-run kcalc
</nowiki>}}
Did it run? If so, then '''congratulations, you just compiled your own version of the KDE calculator (kcalc) from source code!'''
Setting up your environment on a Linux machine is fairly simple. You'll need to install a few programs to get started.
=== Plasma ===
'''[[Plasma|KDE Plasma]]''' is the environment in which you can run apps. Plasma is responsible for providing a desktop with wallpaper, app launchers, and widgets; displaying notifications; managing wired and wireless networks; and similar operating-system level tasks. New versions of Plasma are [[Schedules/Plasma 5|released three times a year]]. Plasma has multiple ''shells'': [https://kde.org/plasma-desktop Plasma Desktop] for desktop, laptop, and 2-in-1 computers, [https://www.plasma-mobile.org/ Plasma Mobile] for mobile phones, [https://plasma-bigscreen.org/ Plasma Bigscreen] for televisions, and so on. They all share certain common components, such as a window manager, networking stack, basic graphical components, and so on. Here is how to build them:
{{CenteredButtonExt|text=Set up a development environment with kdesrc-build|link=https://develop.kde.org/docs/getting-started/building/kdesrc-build-setup/}}
To build the Plasma Desktop environment and its related apps, also build the following:
To get translations in your self-built Plasma, you must build <tt>plasma-workspace</tt> with <code>-DKDE_L10N_SYNC_TRANSLATIONS=true</code>. The easiest way to do this is go into the build directory (<code>~/kde/build/plasma-workspace</code> by default), run <code>ccmake .</code>, turn on that setting, and then rebuild the project.
Now it's time to make your built-from-source Plasma session accessible from the SDDM login screen, and also copy the built-from-source DBus files into a location where they are visible to them system bus. To do this, run the following command:
Once you have a development environment set up, you'll be able to compile single applications or entire software stacks with kdesrc-build. One particular use that kdesrc-build makes convenient is compiling a full KDE Plasma session so you can dive into it.
{{CenteredButtonExt|text=Start compiling KDE software using kdesrc-build|link=https://develop.kde.org/docs/getting-started/building/kdesrc-build-compile/}}
{{Note|SELinux can interfere with the new DBus services working correctly, and the path of least resistance may be to simply turn off enforcement if you are using a distro that ships with it on by default (for example, Fedora). To do this, set the value of <code>SELINUX</code> to <code>permissive</code> in the file <code>/etc/selinux</code>.}}
Once you've made some changes to a piece of KDE software, you'll need to submit those changes to KDE for inclusion in the next release. We use a GitLab instance hosted at invent.kde.org, which has a web interface to manage source code submissions (called "Merge Requests"), and this can be done from the terminal as well.
After this, you can log out and select your new plasma session in SDDM's session chooser menu (which is located in the bottom-left corner of the screen if you're using the Breeze SDDM theme).
{{CenteredButton|text=Submit your new software changes for review|link=Infrastructure/GitLab#Submitting_a_merge_request}}
Alternatively, you can run the new version of plasma on top of your existing system for quick testing like so:
{{Input|1=<nowiki>
source ~/kde/build/plasma-desktop/prefix.sh
~/kde/usr/bin/plasmashell --replace
</nowiki>}}
==== Plasma Mobile ====
Once you've got kdesrc-build set up, you might also want to configure an IDE of your choice for a more convenient workflow. This is optional.
To build the Plasma Mobile environment, also build the following:
You can run your custom-built Plasma Mobile in an emulated phone session using a phone-sized window within your existing desktop. Note that you probably want that this emulated phone session does not use the settings of your current user. E.g. you want in the emulated phone session to use Angelfish, not Mozilla Firefox as your web browser. Instructions:
{{Input|1=<nowiki>
{{CenteredButtonExt|text=Configure the Integrated Development Environment|link=https://develop.kde.org/docs/getting-started/building/ide/}}
Alternative instructions for starting an emulated phone session.
{{Input|1=<nowiki>
Once you've finished learning how to use kdesrc-build, you might see yourself having certain needs, such as managing different branch groups or having separate builds of KDE software based on Qt6 and Qt5. Those topics are covered in the advanced section. This section is optional.
{{CenteredButton|text=Advanced kdesrc-build features and troubleshooting|link=Get_Involved/development/More}}
</nowiki>}}
Plasma Mobile can also be run on a mobile device itself. For more information, see the [[Plasma/Mobile/DevGuide#Mobile_device_running_plasma_mobile|DevGuide]].
== Choose what to work on ==
A good place to start is with a small bug or feature in an existing piece of software that affects you personally ("scratch your own itch"). Get in touch with the existing developers (see [[#Where to find the development team|Where to find the development team]], below) and they can help you out, by pointing you to the right place in the code and giving advice about how to tackle the problem.
=== Iterating on a single project ===
When you're working on a project and you want to rebuild it to test your changes, you can save a lot of time by only rebuilding that project, rather than the entire stack. For example if you are working on <code>plasma-desktop</code>, you can rebuild only that project rather than everything by running <code>kdesrc-build --no-src --no-include-dependencies plasma-desktop</code>.
=== Most important current build issues ===
See [[/More#kdesrc-build_issues|the list of the most important current kdesrc-build build issues]] that affect the Linux distributions that are better suited for kdesrc-build.
=== How to solve build problems ===
Did one or more modules fail to build (displayed in red font) using <code>kdesrc-build</code>? Here's what to do:
# Try building the failing module again from scratch using <code>kdesrc-build [failing module] --refresh-build</code>
# Make sure that you have all the dependencies for the failing module. Go back to the [[#Download non-KDE dependencies]] section and re-install the non-KDE dependencies. If that doesn't fix the problem, open the log file for the failing module which <code>kdesrc-build</code> will print the path at the end of its output. Scroll to the bottom of the log file and read the output to see what missing dependency it is complaining about. Then find and install the corresponding package using the package manager of your distribution. If several look relevant, install them all just to be safe. When you have the necessary dependencies, you can save time and resume from the failing module by adding <code>--resume-from [the name of the module that failed]</code> to your <code>kdesrc-build</code> command.
# Check the [https://build.kde.org/view/Failing/ list of currently broken modules] on the KDE build server. If it's broken there, then it's not your fault. :)
# Ask for help in the the [https://webchat.kde.org/#/room/#kde-devel:kde.org #kde-devel] channel on [[Matrix]] or Libera Chat [[Internet Relay Chat | IRC]]. See [[Get Involved/development#Communicate with the team]]
# Looking into the error log is also helpful. For example, the build stopped at kwallet. You will need to go into <code>kde/src/log/latest/kwallet/error.log</code> and find what packages are missing.
# If you know what files are missing, but you don't know what packages provide them, you can ask your package manager. See https://wiki.archlinux.org/index.php/Pacman/Rosetta (see "Query the package which provides FILE").
# The problem might be in <code>~/kde/usr</code>. E.g. a file in <code>~/kde/usr/include</code> which was renamed or moved. You can help yourself by seeing if you can reproduce this issue in a clean new Virtual Machine (VM). If you cannot reproduce the issue in your VM, then a possible solution is to start with a new and clean kdesrc-build installation. I.e. run something like <code>mv ~/.config/kdesrc-buildrc ~/.config/kdesrc-buildrc~bak ; mv ~/kde ~/kde~bak</code>. Then install kdesrc-build from scratch using this wiki page.
== Submitting changes ==
Now that you can compile and deploy custom versions of KDE software, you can open your editor and start hacking on the source code!
=== Choose what to do ===
A good place to start is with a small bug or feature in an existing piece of software that affects you personally ("scratch your own itch"). Get in touch with the existing developers (see [[#Communicate with the team|Communicate with the team]], below) and they can help you out, by pointing you to the right place in the code and giving advice about how to tackle the problem.
Try not to start by proposing or working on major features or significant design changes. These can be controversial, and the smoothest way to get going is by working on relatively non-controversial bugfixes. Start slowly and build trust!
Try not to start by proposing or working on major features or significant design changes. These can be controversial, and the smoothest way to get going is by working on relatively non-controversial bugfixes. Start slowly and build trust!
Line 302:
Line 75:
* Improve awkwardly-worded messages and labels that are written in English. This is a great way for non-programmers to contribute! If you can compile software and have a good grasp of English, you can make a big difference here.
* Improve awkwardly-worded messages and labels that are written in English. This is a great way for non-programmers to contribute! If you can compile software and have a good grasp of English, you can make a big difference here.
* Work on [https://bugs.kde.org/buglist.cgi?bug_status=UNCONFIRMED&bug_status=CONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&keywords=junior-jobs&list_id=1340815 Junior Jobs], which are small tasks that are suitable for beginners (both bugs and features).
* Work on Junior Jobs, which are small tasks that are suitable for beginners (both bugs and features). You can find them available both on [https://bugs.kde.org/buglist.cgi?bug_status=UNCONFIRMED&bug_status=CONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&keywords=junior-jobs&list_id=1340815 Bugzilla] and [https://invent.kde.org/dashboard/issues?sort=created_date&state=opened&label_name%5B%5D=Junior+Job Gitlab].
* Work on [https://bugs.kde.org/buglist.cgi?bug_status=UNCONFIRMED&bug_status=CONFIRMED&bug_status=ASSIGNED&bug_status=REOPENED&keywords=usability&keywords_type=allwords&list_id=1493316&order=product%2Cchangeddate%20DESC%2Cbug_status%20DESC%2Cresolution%2Cpriority%2Cassigned_to%2Cbug_id&query_format=advanced Bugs related to] KDE's [[Goals/Usability_%26_Productivity | Usability & Productivity initiative]], many of which are small and easy.
* Work on [https://bugs.kde.org/buglist.cgi?bug_status=UNCONFIRMED&bug_status=CONFIRMED&bug_status=ASSIGNED&bug_status=REOPENED&keywords=usability&keywords_type=allwords&list_id=1493316&order=product%2Cchangeddate%20DESC%2Cbug_status%20DESC%2Cresolution%2Cpriority%2Cassigned_to%2Cbug_id&query_format=advanced Bugs related to] KDE's [[Goals/Usability_%26_Productivity | Usability & Productivity initiative]], many of which are small and easy.
The code for the version of the KDE Calculator (kcalc) that you built earlier is located at <code>~/kde/src/kcalc</code>; other projects you build with <code>kdesrc-build</code> will live in similar locations.
You may wish to look over the [[/IDE_configuration|instructions for setting up an Integrated Development Environment (IDE)]] for development with KDE projects. You can use the debugger inside an IDE to go over the lines of source code that you change.
== Source code cross-referencing ==
Once you've made some changes, make sure the project still compiles and installs, and make sure the changes have the desired effect when you run the software. Then it's time to run the project's test suite:
{{Input|1=<nowiki>
cd ~/kde/build/kcalc
source prefix.sh
ctest --output-on-failure # or make test
</nowiki>}}
If any test fails, that needs to be investigated and fixed before you can proceed. Once the tests pass, then run the software again to make sure it still behaves properly. If it doesn't, then go back and work on your patch some more, then re-compile and re-deploy, and test again, until the program does what you'd like it to do and all tests pass.
=== How to run an application after making changes to one of its dependencies ===
Build the application that you want to build. E.g. kcalc (the KDE calculator):
<pre>
kdesrc-build kcalc
</pre>
This will also build all of the KDE git repositories on which kcalc depends such as e.g. the KDE Frameworks 5 library kconfig.
The command line above has cloned the KDE git repository https://invent.kde.org/frameworks/kconfig in the directory <code>~/kde/src/kconfig</code>. Has built kconfig in the directory <code>~/kde/build/kconfig</code>. And has installed kconfig in the directory <code>~/kde/usr</code>.
Now you want to make a change to kconfig. E.g. You edit the file <code>~/kde/src/kconfig/src/core/kauthorized.h</code>.
Because <code>kdesrc-build</code> will do git operations in the directory <code>~/kde/src/kconfig</code>, you want to use the <code>kdesrc-build</code> parameter <code>--no-src</code>.
Because <code>kdesrc-build</code> does not always write the needed files to <code>~/kde/usr</code>, you want to use the <code>kdesrc-build</code> parameter <code>--refresh-build</code>.
So, in order to build and install kconfig correctly, you can use the command line:
Once you're happy with your patch and have verified that it does what you want, it's time to submit your changes for the review!
KDE uses their own GitLab instance called [https://invent.kde.org Invent] for submitting merge requests and code review. See the [[Infrastructure/GitLab#Submitting_a_merge_request|GitLab page]] to learn how to submit a merge request.
=== Communicate with the team ===
There are several ways to get in touch with KDE developers, either generally or for a specific project. The most important communications channels are:
* The [https://webchat.kde.org/#/room/#kde-devel:kde.org #kde-devel] channel on [[Matrix]] or the Libera Chat [[Internet Relay Chat | IRC]], which is where KDE developers chat in real-time about their work.
* The [https://mail.kde.org/mailman/listinfo/kde-devel kde-devel mailing list] is the primary development mailing list. [http://kde.org/support/#mailinglists Learn more about mailing lists].
These are general KDE development communication channels, and you may get directed to a more appropriate place for the project you are interested in. There is a [http://www.kde.org/mailinglists/ list of mailing lists] if you want to find a mailing list for a specific team directly. Many teams have their own real-time chat channels, too.
You can also try looking for the team's section on the [[Main Page]] of this wiki. Many teams have information there for new contributors.
== Source code cross referencing ==
To search for a class, method, signal name... etc in all KDE repos, KDE uses a code referencing tool to index code in the various KDE repositories, you can search using the web interface available at https://lxr.kde.org/ . This is a very useful tool if you e.g. want to search for code usage examples in existing code... etc.
To search for a class, method, signal name... etc in all KDE repos, KDE uses a code referencing tool to index code in the various KDE repositories, you can search using the web interface available at https://lxr.kde.org/ . This is a very useful tool if you e.g. want to search for code usage examples in existing code... etc.
Line 376:
Line 92:
Other ways to search across all of the KDE git repositories:
Other ways to search across all of the KDE git repositories:
* If you have a github.com account. Log into github.com. Go to https://github.com/KDE , in the top left search bar, search for your search term e.g. <code>KMessageBox</code>, select "In this organization".
* If you have a github.com account. Log into github.com. Go to https://github.com/KDE , at the top of the page in the search bar ("Type / to search"), write your search term e.g. <code>KMessageBox</code>, select "In this organization". In order to search case sensitive and whole words, you can use case sensitive regex e.g. <code>org:KDE /(?-i)\bKMessageBox\b/</code>.
* <code>kdesrc-build --src-only</code> will download the source code of more than 300 KDE git repositories in <code>~/kde/src</code>. Search inside this directory. E.g. using Microsoft Visual Studio Code <code>code ~/kde/src</code>, from the vscode main menu > Edit > Find in Files Ctrl+Shift+F.
* <code>kdesrc-build --src-only</code> will download the source code of more than 300 KDE git repositories in <code>~/kde/src</code>. Search inside this directory. E.g. using Microsoft Visual Studio Code, from a terminal run the command line <code>code ~/kde/src</code>, from the vscode main menu > Edit > Find in Files Ctrl+Shift+F.
== Next steps ==
== Next steps ==
Sharpen your skills by going through the [https://develop.kde.org/docs/use/ KDE development tutorials].
Sharpen your skills by going through the [https://develop.kde.org/docs/ KDE development tutorials].
After you have had several drama-free patches accepted, a KDE developer is likely to suggest you get a [[Infrastructure/Get a Developer Account|Developer account]], which will allow you to commit directly to KDE projects. With very few limits on where you can commit, you will be expected to act responsibly. At this point, congratulations! You are officially a KDE developer!
After you have had several drama-free patches accepted, a KDE developer is likely to suggest you get a [[Infrastructure/Get a Developer Account|Developer account]], which will allow you to commit directly to KDE projects. With very few limits on where you can commit, you will be expected to act responsibly. At this point, congratulations! You are officially a KDE developer!
== Best practices & other useful information==
== Best practices & other useful information ==
* [[Get Involved/Design/Lessons Learned|Lessons learned over time regarding the development of user-facing software]]
* [[Get Involved/Design/Frequently Discussed Topics|Frequently discussed topics and lessons learned regarding the development of user-facing GUI software]]
* [[Guidelines_and_HOWTOs/Debugging|Debugging]]
* [[Guidelines_and_HOWTOs/Debugging|Debugging]]
* [[Guidelines and HOWTOs/UnitTests|Unit testing]]
* [[Guidelines and HOWTOs/UnitTests|Unit testing]]
Line 392:
Line 109:
* [[Guidelines and HOWTOs/Licensing|Correctly state license information]]
* [[Guidelines and HOWTOs/Licensing|Correctly state license information]]
* [[Frameworks/Porting_Notes|Porting from KDE 4 to Frameworks 5]]
* [[Guidelines_and_HOWTOs/Making_apps_run_uninstalled|Running applications and their unit tests without first installing them]]
* [[Guidelines_and_HOWTOs/Making_apps_run_uninstalled|Running applications and their unit tests without first installing them]]
* [https://community.kde.org/Infrastructure/GitLab#Testing_someone_else.27s_Merge_Request How to review merge requests]
* [[Infrastructure/GitLab#Testing_someone_else's_merge_request|How to review merge requests]]
* [https://github.com/Wenzel/docker-kdesrc-build How to build with Docker]
== More ==
== Advanced Topics ==
This page continues with [[Get_Involved/development/More|more advanced topics]].
This page continues with [[Get_Involved/development/More|more advanced topics]].
Revision as of 05:14, 26 July 2024
By joining the ranks of KDE developers, you will get to implement new features and defeat bugs both daunting and simple. Developers collaborate in teams based on what area they are working on. These can be small teams working on a single application, up to large teams working on a group of related pieces of software, or even meta-teams working on broader topics such as QA or automation. Many developers participate in more than one team.
KDE runs or participates in several mentoring programs to help new developers, including an informal list of people who are willing to help newcomers get started. See the Mentoring page for more details.
Where to find the development team
The KDE developers are here to assist you if you need any help following this guide.
There are several ways to get in touch with KDE developers, either generally or for a specific project. The most important communication channels are:
These are general KDE development communication channels, and you may be directed to a more appropriate place for the project you're interested in.
Many projects and teams have their own real-time chat channels, which can be found on the Matrix Rooms page.
There is a list of mailing lists if you want to find a mailing list for a specific team directly.
The Main Page of this wiki includes links to specific development teams and the Get Involved page includes links to more general contribution teams.
Prerequisites
Skills
Most KDE software is written in C++ using the Qt toolkit and KDE Frameworks. Though prior experience with these technologies or other programming languages is helpful, you don't need to be a C++ programmer to get started! For example, no programming knowledge whatsoever is required to do things like improving text labels.
For KDE development, we recommend a Linux operating system installed on your computer or in a virtual machine. The ones best suited for development provide relatively recent versions of libraries needed by KDE software, and use the "rolling release" model. Some examples are Arch Linux, openSUSE Tumbleweed, and KDE neon. The latest version of Fedora KDE usually works as well.
We recommend that you use the KDE Plasma desktop on your Linux operating system.
The main way to develop KDE software: kdesrc-build
KDE uses a custom tool called kdesrc-build for setting up a development environment and building KDE software. You only need to set up your environment once, and then you can compile (and recompile) KDE software as often as needed.
Setting up your environment on a Linux machine is fairly simple. You'll need to install a few programs to get started.
Once you have a development environment set up, you'll be able to compile single applications or entire software stacks with kdesrc-build. One particular use that kdesrc-build makes convenient is compiling a full KDE Plasma session so you can dive into it.
Once you've made some changes to a piece of KDE software, you'll need to submit those changes to KDE for inclusion in the next release. We use a GitLab instance hosted at invent.kde.org, which has a web interface to manage source code submissions (called "Merge Requests"), and this can be done from the terminal as well.
Once you've finished learning how to use kdesrc-build, you might see yourself having certain needs, such as managing different branch groups or having separate builds of KDE software based on Qt6 and Qt5. Those topics are covered in the advanced section. This section is optional.
A good place to start is with a small bug or feature in an existing piece of software that affects you personally ("scratch your own itch"). Get in touch with the existing developers (see Where to find the development team, below) and they can help you out, by pointing you to the right place in the code and giving advice about how to tackle the problem.
Try not to start by proposing or working on major features or significant design changes. These can be controversial, and the smoothest way to get going is by working on relatively non-controversial bugfixes. Start slowly and build trust!
Here are some other ideas for starting points:
Improve awkwardly-worded messages and labels that are written in English. This is a great way for non-programmers to contribute! If you can compile software and have a good grasp of English, you can make a big difference here.
Work on Junior Jobs, which are small tasks that are suitable for beginners (both bugs and features). You can find them available both on Bugzilla and Gitlab.
To search for a class, method, signal name... etc in all KDE repos, KDE uses a code referencing tool to index code in the various KDE repositories, you can search using the web interface available at https://lxr.kde.org/ . This is a very useful tool if you e.g. want to search for code usage examples in existing code... etc.
Usage:
From the Branch group menu, you can select either kf5-qt5, to search the code in the Git master branches or stable-kf5-qt5 to search only the stable (released) branches
There are two search modes:
On the Identifier search page, you can search for (note that this is case sensitive):
class names, e.g. RenameDialog, StatJob, and of course any Qt class (used in KDE code, which is pretty much all of them), QLatin1String, QListWidget
method names, e.g. addConfigSources() (from the KConfig framework) and signal names e.g. mimeTypeFound()
on the General search page, you can search for strings, e.g. in Dolphin's context menu (accessed by right- clicking any empty space) there is Paste Clipboard Contents, if you want to find in which source file this string is defined, search for Paste Clipboard Contents; this search includes classes/methods/signals names.
Other ways to search across all of the KDE git repositories:
If you have a github.com account. Log into github.com. Go to https://github.com/KDE , at the top of the page in the search bar ("Type / to search"), write your search term e.g. KMessageBox, select "In this organization". In order to search case sensitive and whole words, you can use case sensitive regex e.g. org:KDE /(?-i)\bKMessageBox\b/.
kdesrc-build --src-only will download the source code of more than 300 KDE git repositories in ~/kde/src. Search inside this directory. E.g. using Microsoft Visual Studio Code, from a terminal run the command line code ~/kde/src, from the vscode main menu > Edit > Find in Files Ctrl+Shift+F.
After you have had several drama-free patches accepted, a KDE developer is likely to suggest you get a Developer account, which will allow you to commit directly to KDE projects. With very few limits on where you can commit, you will be expected to act responsibly. At this point, congratulations! You are officially a KDE developer!
