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[[File:Mascot konqi-app-dev.png|right|x250px|]]
== Becoming a KDE Developer ==
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.


[[File:Konqui dev close cropped.png|right|x200px|]]
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.
By joining the ranks of KDE developers, you will get to implement new features and defeat daunting bugs, 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 group of related pieces of software. Many developers are in more than one team.
 
== 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])
 
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|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 ==
 
=== 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 improving text labels.


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 ===
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.
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 [[/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.
== 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.


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.


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


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 [[#Communicating with the team|Communicating 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.


Other starting points are:
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.


* [https://bugs.kde.org/buglist.cgi?bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&keywords=junior-jobs&list_id=1340815 Junior Jobs] are small tasks that are suitable for beginners (both bugs and features)
* [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


== Communicating with the team ==
{{CenteredButtonExt|text=Start compiling KDE software using kde-builder|link=https://develop.kde.org/docs/getting-started/building/kde-builder-compile/}}


There are several ways to get in touch with KDE developers, and developers for a specific project. The two most important are:


* the IRC channel [irc://irc.kde.org/kde-devel <nowiki>#kde-devel</nowiki>] on [http://freenode.net/ the freenode network] ([http://kde.org/support/#irc learn more about IRC]) is the core channel for developers
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.
* the primary development mailing list is the [https://mail.kde.org/mailman/listinfo/kde-devel kde-devel list] ([http://kde.org/support/#mailinglists learn more about mailing lists])


{{CenteredButton|text=Submit your new software changes for review|link=Infrastructure/GitLab#Submitting_a_merge_request}}


Both of 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.


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.
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.


==New to (C++/Qt) software development?==


Most KDE software is written in C++ using the [https://www.qt.io Qt framework]. There are many guides to C++ online, and which one works for you will depend on how you learn best and what previous programming experience you have.
{{CenteredButtonExt|text=Configure the Integrated Development Environment|link=https://develop.kde.org/docs/getting-started/building/ide/}}


For learning Qt, you can find [https://wiki.qt.io/Books a list of books for learning Qt] on the Qt wiki. Qt also provides [http://doc.qt.io/qt-5/qtexamplesandtutorials.html lots of examples] you can look at.


Most KDE software is also built on other KDE software, particularly the KDE Frameworks. The [https://techbase.kde.org TechBase wiki] has documentation about using these libraries, and a [[Books | book]] is available. See also [[Guidelines and HOWTOs/Development]].
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.


==Getting the code==
{{CenteredButton|text=Advanced kde-builder features and troubleshooting|link=Get_Involved/development/More}}


Source code for KDE projects can be found in the KDE Git repositories. These are listed in our [https://commits.kde.org/ repository browser], and the URLs you need to clone can be found there as well. If you are not familiar with [https://git-scm.com/ Git], the [https://git-scm.com/book Git Book] is a good introduction, although all you really need right now is
== 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.


{{Input|1=git clone <nowiki>https://anongit.kde.org/<repository-name>.git</nowiki>}}
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!


For almost all KDE software projects, you will need to use [https://www.cmake.org CMake] to build them. On UNIX systems, the process is fairly straightforward:
Here are some other ideas for starting points:


{{Input|1=mkdir build
* 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.
cd build
* 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].
cmake -DCMAKE_INSTALL_PREFIX=/where/you/want/to/install/it ..
* 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.
make
* Write [[App ideas|small useful apps]].
make install}}


The CMake step will complain if you don't have the project's dependencies installed (don't forget that on many Linux distributions, you need to install the development version of packages). Once you have installed the things it tells you, re-run CMake so it picks them up. If you want a way to get the latest versions of all the dependencies easily, you might want to consider looking at [http://neon.kde.org.uk/ KDE Neon].
== Source code cross-referencing ==


Hopefully the project has unit tests, which can be run with
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.


{{Input|1=make test}}
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.


Now you can open your editor and get hacking!
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.


=Submitting your first patch=
== Next steps ==
Sharpen your skills by going through the [https://develop.kde.org/docs/ KDE development tutorials].


Once you have made a change, you need to send it to someone on the team to review it and (hopefully) apply it. You should find out from the team what their preferred method is, but for most teams it will be uploading the patch to [https://phabricator.kde.org Phabricator]. You will need a [https://identity.kde.org KDE Identity] account to log in.
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!


; [https://phabricator.kde.org Phabricator]
== Best practices & other useful information ==
: The preferred way to submit a patch is through the [https://secure.phabricator.com/book/phabricator/article/arcanist/ Arcanist] command line too. You can also use the Phabricator web interface (after logging in, go to [https://phabricator.kde.org/differential/ Differential] (on the left menu), choose [https://phabricator.kde.org/differential/diff/create/ Create Diff] (in the top right) and follow the instructions), but then be prepared to communicate your email address if the patch is accepted, so that it can have the proper credits. More detailed documentation about the KDE instance of Phabricator [https://community.kde.org/Infrastructure/Phabricator is available].


==Next steps==
* [[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/UnitTests|Unit testing]]
* [[Guidelines and HOWTOs/Code_Checking| Validating code]]
* [[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/Making_apps_run_uninstalled|Running applications and their unit tests without first installing them]]
* [[Infrastructure/GitLab#Testing_someone_else's_merge_request|How to review merge requests]]


After you have had several 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. There will be very few limits on where you can commit, so you are expected to act responsibly. At this point, congratulations! You are officially a KDE developer!
== Advanced Topics ==


You may also want to set up a more permanent or advanced development environment, which will be very handy to start working on KDE Frameworks or Plasma itself. See [[Guidelines and HOWTOs/Build from source]]
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.



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.



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



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.

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.