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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.


{{Info|While any operating system can be used to patch or develop KDE software, it's easiest if you use a Linux distribution that provides relatively recent versions of Qt and KDE Frameworks, such as Arch/Manjaro, Fedora, KDE Neon, openSUSE Tumbleweed, or non-LTS versions of Ubuntu.<br /><br />Support for distros that ship older software (such as Debian, Ubuntu/Kubuntu 18.04, and openSUSE Leap 15) is still experimental and you may have a better experience developing with one of the distributions mentioned above in a virtual machine.}}
== 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:
* '''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])


== New to C++/Qt software development? ==
These are general KDE development communication channels, and you may be directed to a more appropriate place for the project you're interested in.
Most KDE software is written in C++ using the [https://www.qt.io Qt toolkit] and [[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.


{{Note|The Qt wiki contains [https://wiki.qt.io/Books a list of online books] for learning Qt programming. Qt also provides [http://doc.qt.io/qt-5/qtexamplesandtutorials.html lots of examples] you can look at. Information about KDE Frameworks can be found on the [https://techbase.kde.org TechBase wiki], and a [[Books | book]] is available.}}
* 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.


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 ==


== One-time setup: your development environment ==
=== Skills ===
To build software, you need 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 (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!
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.


{{Note|'''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!}}
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]].


=== Operating system ===


=== Install basic tools ===
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, Solus and KDE neon User Edition. The latest version of Fedora KDE usually works as well.
First you will need to use your operating system's package manager to install some basic tools:
* Arch/Manjaro: <code>sudo pacman -S git cmake dialog</code>
* Fedora: <code>sudo dnf install git cmake dialog perl</code>
* KDE Neon/Kubuntu/Ubuntu/Debian: <code>sudo apt install git cmake dialog</code>
* openSUSE Leap & Tumbleweed: <code>sudo zypper install git cmake dialog</code>
<br />


We recommend that you use the KDE Plasma desktop on your Linux operating system.


=== Enable the source repositories ===
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.
Some operating systems also require that you enable on the source repositories before you can install build dependencies (more about that later). Do that now, if necessary:
* Kubuntu/Ubuntu/Debian: <code>sudo sed -i '/deb-src/s/^# //' /etc/apt/sources.list && sudo apt update</code> (for more information, see https://askubuntu.com/questions/158871/how-do-i-enable-the-source-code-repositories)
* openSUSE Leap & Tumbleweed: <code>sudo zypper mr -e $(zypper repos | awk '/source/{print $5}'))</code>


== The main way to develop KDE software: kde-builder ==


=== Configure Git ===
KDE uses a custom tool called '''kde-builder''' 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.
We need to set your authorship information properly so that any changes you make can be properly attributed to you:
{{Input|1=<nowiki>
git config --global user.name "Your Name"
git config --global user.email "you@email.com"
</nowiki>}}


{{Note|The name you provide should be your actual name, not your KDE Identity username.
Setting up your environment on a Linux machine is fairly simple. You'll need to install a few programs to get started.
<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 <tt>BUG: </tt> and <tt>FEATURE: </tt> keywords won't work (see [https://techbase.kde.org/Development/Git/Configuration#Basic_Settings this page] for more information).}}


=== Set up kdesrc-build ===
{{CenteredButtonExt|text=Set up a development environment with kde-builder|link=https://develop.kde.org/docs/getting-started/building/kde-builder-setup/}}
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.


Most Linux-based operating systems do not provide development packages that are up-to-date enough for working on KDE software, so we will compile all the KDE dependencies ourselves. To do this, we use a command-line tool called <code>kdesrc-build</code> to download, manage, and build KDE source code repositories. Let's set it up now:


{{Input|1=<nowiki>
Once you have a development environment set up, you'll be able to compile single applications or entire software stacks with kde-builder. One particular use that kde-builder makes convenient is compiling a full KDE Plasma session so you can dive into it.
mkdir -p ~/kde/src
cd ~/kde/src/
git clone git://anongit.kde.org/kdesrc-build.git
</nowiki>}}


This has "cloned" the source code repository that holds <code>kdesrc-build</code>, so you have a local copy of it on your computer.


Next we want to add the <code>kdesrc-build</code> program to your system's <tt>$PATH</tt> variable so you can access it from anywhere, not just when you're inside <tt>~/kde/src/kdesrc-build</tt>. Use a text editor to open the <tt>~/.bashrc</tt> file and add a new line containing <code>export PATH=~/kde/src/kdesrc-build:$PATH</code>.  Then save the file, close it, and run <code>source ~/.bashrc</code> to pick up the changes.
{{CenteredButtonExt|text=Start compiling KDE software using kde-builder|link=https://develop.kde.org/docs/getting-started/building/kde-builder-compile/}}


Next, it's time to set up <code>kdesrc-build</code> using its built-in wizard. Feel free to customize anything, but running it with the default options should be ok:
{{Input|1=<nowiki>
kdesrc-build --initial-setup
</nowiki>}}
{{Note|Do not quote or escape any file paths entered in the wizard! And do not run the command <code>kdesrc-build</code> by itself without any arguments because this will build everything, which is probably overkill right now.}}


This command does two things. First, it tries to install the basic packages for compiling Qt and KDE software on your distro. Second, it creates a <code>~/.kdesrc-buildrc</code> configuration file.
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.


By default, <code>kdesrc-build</code> will build all the dependencies that a program or framework needs, including the Qt toolkit itself. If your Linux distribution provides a recent version of Qt (>= 5.11), you can save some time and disk space and use that version instead of building your own. To configure <code>kdesrc-build</code> to skip building Qt, open the configuration file <code>~/.kdesrc-buildrc</code> and comment out the <code>qtdir</code> and two <code>include</code> lines related to qt5.
{{CenteredButton|text=Submit your new software changes for review|link=Infrastructure/GitLab#Submitting_a_merge_request}}


If you further don't want <code>kdesrc-build</code> to build all dependencies as the default behavior 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'''.


If you want a more guided setup process for <code>kdesrc-build</code>, run the command <code>kdesrc-build-setup</code> instead. However, unlike <code>--initial-setup</code>, it won't install packages from your distro for compiling programs so you will have to do that yourself.
Once you've got kde-builder set up, you might also want to configure an IDE of your choice for a more convenient workflow. This is optional.


Consult the [https://docs.kde.org/trunk5/en/extragear-utils//kdesrc-build/ kdesrc-build manual] for more information and options.


{{CenteredButtonExt|text=Configure the Integrated Development Environment|link=https://develop.kde.org/docs/getting-started/building/ide/}}


=== Download non-KDE dependencies ===
Even though <code>kdesrc-build</code> will take care of the KDE dependencies for you, it does not yet have the ability to install non-KDE dependencies (see https://bugs.kde.org/show_bug.cgi?id=402428), which are typically acquired using your package manager. To install the required non-KDE dependencies, [[Guidelines and HOWTOs/Build from source/Install the dependencies|read this page]] and follow the instructions laid out there.


Once that's done, your development environment is set up and ready to build software! Let's take it for a spin.
Once you've finished learning how to use kde-builder, 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 kde-builder features and troubleshooting|link=Get_Involved/development/More}}


 
== Choose what to work on ==
== Build some software ==
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.
{{Note|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 dependencies (See https://invent.kde.org/kde/kdesrc-build/issues/17). 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.}}
 
=== Applications ===
'''[[KDE Applications]]''' like Dolphin, Okular, Konsole and 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/Applications/18.12 Release Schedule|released three times a year]]. Note that the Discover app store (git repo name: <tt>plasma-discover</tt>) and System Settings app (git repo name: <tt>systemsettings</tt>) are distributed alongside Plasma, but they build like apps app using the below instructions. A list of all KDE applications can be found here: https://userbase.kde.org/Applications.
 
For example, here is how to build Dolphin, the KDE file manager:
 
{{Input|1=<nowiki>
kdesrc-build dolphin --include-dependencies
</nowiki>}}
 
As a part of this process, Dolphin was installed to <tt>~/kde/usr/bin/dolphin</tt>. '''There is no need to manually install anything;''' <tt>kdesrc-build</tt> installed it for you! <tt>Source</tt> the project's auto-generated <tt>prefix.sh</tt> file every time you want to run your custom-compiled version of Dolphin:
 
{{Input|1=<nowiki>
source ~/kde/build/dolphin/prefix.sh
~/kde/usr/bin/dolphin
</nowiki>}}
 
Did it run? If so, then '''congratulations, you just compiled your own version of Dolphin from source code!'''
 
 
=== Frameworks ===
'''[[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 frameworks can be found here: https://api.kde.org/frameworks/index.html.
 
For example, here is how to build the KIO framework:
 
{{Input|1=<nowiki>
kdesrc-build kio  --include-dependencies
</nowiki>}}
 
Now you can run an existing app using your custom-made version of the framework! For example, the following will run Dolphin, but it will be using the KIO library that you just built:
 
{{Input|1=<nowiki>
source ~/kde/build/kio/prefix.sh
~/kde/usr/bin/dolphin
</nowiki>}}
 
 
=== 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]].
 
Here is how to build the Plasma desktop environment, including its window manager and its built-in apps:
 
{{Input|1=<nowiki>
kdesrc-build plasma-desktop plasma-workspace plasma-framework plasma-nm plasma-pa plasma-thunderbolt plasma-vault plasma-workspace-wallpapers kdeplasma-addons kwin systemsettings kscreen breeze discover kinfocenter --include-dependencies
</nowiki>}}
 
To run your custom-built Plasma, first make it accessible from the SDDM login screen by running the following command:
{{Input|1=<nowiki>
sudo ~/kde/build/plasma-workspace/login-sessions/install-sessions.sh
</nowiki>}}
 
After that, 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)
 
There are a few quirks to keep in mind when running your custom-compiled Plasma:
 
===== KAuth & Polkit applications =====
{{Note|This step is optional, but you will need to do it if you want to develop or use apps that display password dialogs.}}
Because we installed Plasma to a custom path, KAuth and Polkit need to be made aware of it. Run the following commands:
<syntaxhighlight lang="bash">
sudo ln -s /home/$USER/kde/usr/etc/dbus-1/system.d/*  /etc/dbus-1/system.d/.
sudo ln -s /home/$USER/kde/usr/etc/polkit-1/rules.d*  /etc/polkit-1/rules.d/.
</syntaxhighlight>
 
===== DBus =====
{{Note|This step is optional, but your Plasma session may experience quirky behavior without it.}}
Just like KAuth and PolKit, DBus is not aware of the new Plasma installation and needs to be informed. Unfortunately, unlike Kauth and PolKit, DBus can only be given one path at a time, so we will need to change the path that DBus looks at whenever you use your new Plasma session. Create a file <tt>/etc/dbus-1/session-local.conf.bak</tt> with the following contents:
<pre>
<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
<servicedir>/home/$USER/kde/usr/share/dbus-1/services</servicedir>
</busconfig>
</pre>
 
Create another file <tt>/etc/dbus-1/system-local.conf.bak</tt> with the following contents:
<pre>
<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
<servicedir>/home/$USER/kde/usr/share/dbus-1/system-services</servicedir>
<includedir>/home/$USER/kde/usr/etc/dbus-1/system.d</includedir>
</busconfig>
</pre>
 
Before logging into your new compiled-from-source Plasma session, rename the files like so:
<syntaxhighlight lang="bash">
sudo mv /etc/dbus-1/session-local.conf.bak /etc/dbus-1/session-local.conf
sudo mv /etc/dbus-1/system-local.conf.bak /etc/dbus-1/system-local.conf
</syntaxhighlight>
 
Then before you log out and return to your normal distro-provided Plasma session, rename them like so:
<syntaxhighlight lang="bash">
sudo mv /etc/dbus-1/session-local.conf /etc/dbus-1/session-local.conf.bak
sudo mv /etc/dbus-1/system-local.conf /etc/dbus-1/system-local.conf.bak
</syntaxhighlight>
 
=== 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 your distro's package manager your distro. If several looks relevant, install them all just to be safe.
# Check the [https://build.kde.org/view/FAILED/ 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 freenode [[Internet Relay Chat | IRC]]. See [[Get Involved/development#Communicate with the team]]
 
 
 
== Choose what to do ==
Now that you can compile and deploy custom versions of KDE software, you can open your editor and start hacking on the source code! The code for the version of Dolphin that you built earlier is located at <tt>~/kde/src/dolphin/</tt>; other projects you build with <code>kdesrc-build</code> will live in similar locations.
 
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 208: 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.
* [http://www.englishbreakfastnetwork.org/ The English Breakfast Network] searches out simple, common issues in code that should be fixed, and going through the problems on there can provide a good overview of the code.
* Write [[App ideas|small useful apps]].
 
 
 
== Test your changes ==
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 unit tests:


{{Input|1=<nowiki>
== Source code cross-referencing ==
cd ~/kde/build/dolphin/
source ./prefix.sh
ctest --output-on-failure
</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.
To search for an identifier (e.g. class name, method name, signal name) or for free-text search in all KDE git repositories, KDE provides a code referencing tool 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.
 
 
 
== Submit a patch ==
Once you're happy with your patch and have verified that it does what you want, it's time to '''generate a diff.''' A diff is a textual representation of the differences between original versions of the files you changed, and the new ones you've produced. You can generate a diff by entering the source repository and running <code>git diff</code>, but we recommend using the <code>arc</code> tool, which will generate a diff and submit it for review very quickly and easily! You can learn how to set it up [https://community.kde.org/Infrastructure/Phabricator#Using_Arcanist_to_post_patches here].
 
KDE uses [https://phabricator.kde.org Phabricator] for patch submission and review. [[Infrastructure/Phabricator|Learn more about how to submit a patch with Phabricator]].
 
 
 
== 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 freenode [[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.


Usage:
* From the '''Branch group''' menu, you can select either '''kf6-qt6''', to search the code in the Git ''master'' branches or '''stable-kf6-qt6''' 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. <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>kde-builder --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://techbase.kde.org/Development/Tutorials KDE development tutorials]. And try out [http://www.kdevelop.org KDevelop], the KDE IDE.
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 do git commits directly to KDE projects without the need of GitLab forks. 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!


You may also want to set up a more customized development environment. See [[Guidelines and HOWTOs/Build from source]].
== Best practices & other useful information ==


 
* [[Get Involved/Design/Frequently Discussed Topics|Frequently discussed topics and lessons learned regarding the development of user-facing GUI software]]
 
== Best practices & other useful information==
* [[Guidelines_and_HOWTOs/Debugging|Debugging]]
* [[Guidelines_and_HOWTOs/Debugging|Debugging]]
* [[Guidelines and HOWTOs/UnitTests|Unit testing]]
* [[Guidelines and HOWTOs/UnitTests|Unit testing]]
* [[Guidelines and HOWTOs/Code_Checking| Validating code]]
* [[Guidelines and HOWTOs/Code_Checking| Validating code]]
* [[Guidelines and HOWTOs/API Documentation|Writing API documentation]] (related: https://api.kde.org).
* [[Guidelines and HOWTOs/API Documentation|Writing API documentation]] (related: https://api.kde.org).
* [[Guidelines and HOWTOs/Licensing|Correctly state license information]]
* [[Guidelines_and_HOWTOs/Wayland_Porting_Notes|Writing Wayland-friendly code]]
* [[Guidelines_and_HOWTOs/Wayland_Porting_Notes|Writing Wayland-friendly code]]
* [[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/Phabricator#How_to_review_someone_else.27s_patch How to review patches]
* [[Infrastructure/GitLab#Testing_someone_else's_merge_request|How to review merge requests]]
 
== Advanced Topics ==
 
This page continues with [[Get_Involved/development/More|more advanced topics]].

Latest revision as of 18:21, 26 October 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.

If you'd like to dive deeper, the Qt wiki contains a list of online books for learning Qt programming. Qt also provides lots of examples you can look at. For visual learners, this YouTube playlist of QML tutorials by KDE patron KDAB may be useful. Finally, information about KDE Frameworks can be found on the KDE Developer Platform and KDE API website. We also provide a wiki page full of learning resources.

Operating system

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, Solus and KDE neon User Edition. The latest version of Fedora KDE usually works as well.

We recommend that you use the KDE Plasma desktop on your Linux operating system.

Support for Windows and macOS are still experimental, and you may have a better experience doing your development in a virtual machine using a Linux distribution. Setting up a development environment on other operating systems--including FreeBSD--is an advanced topic.

The main way to develop KDE software: kde-builder

KDE uses a custom tool called kde-builder 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.


Set up a development environment with kde-builder


Once you have a development environment set up, you'll be able to compile single applications or entire software stacks with kde-builder. One particular use that kde-builder makes convenient is compiling a full KDE Plasma session so you can dive into it.


Start compiling KDE software using kde-builder


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.

Submit your new software changes for review


Once you've got kde-builder set up, you might also want to configure an IDE of your choice for a more convenient workflow. This is optional.


Configure the Integrated Development Environment


Once you've finished learning how to use kde-builder, 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.

Advanced kde-builder features and troubleshooting

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, 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.
  • Work on Bugs related to KDE's Usability & Productivity initiative, many of which are small and easy.
  • Write small useful apps.

Source code cross-referencing

To search for an identifier (e.g. class name, method name, signal name) or for free-text search in all KDE git repositories, KDE provides a code referencing tool 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.

Usage:

  • From the Branch group menu, you can select either kf6-qt6, to search the code in the Git master branches or stable-kf6-qt6 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/.
  • kde-builder --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.

Next steps

Sharpen your skills by going through the KDE development tutorials.

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 do git commits directly to KDE projects without the need of GitLab forks. 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

Advanced Topics

This page continues with more advanced topics.

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