User:Nmariusp/Easy

I know how to program using C++. Can I do a KDE MR in less than 2 hours?

Below are some easy ways to do merge requests (MR) for the KDE git repositories. And easy ways to contribute to the KDE Community.

You can find here instructions on how to open a KDE git repository in the IDE Qt Creator. After you build that KDE git repository using kdesrc-build.

See similar lists and web pages for more ideas Marble, Calligra, 1, 2.

You should be able to build all 400 KDE git repositories using kdesrc-build

From time to time, make sure that all the KDE git repositories (continue to) build correctly using kdesrc-build. Run: kdesrc-build without parameters. That will build all 400 KDE git repositories. If a KDE git repository was building successfully last week, but does not build successfully today, invest time to investigate why it stopped building in a timeboxed manner. E.g. invest 10 minutes. Then, if needed, ask in the KDE Matrix room "KDE New Contributors" ( https://go.kde.org/matrix/#/#new-contributors:kde.org https://community.kde.org/Matrix ) if this module is supposed to build.

Example: let's say that kcalc does not build. In konsole, I would run:

kdesrc-build kcalc --no-src --no-include-dependencies --refresh-build --debug |& tee ~/a.txt

In the web browser create a pastebin. E.g. https://pastebin.centos.org/ Paste the contents of the file ~/a.txt. Paste the URL of the new pastebin in the KDE matrix channel when requesting help.

Proofreading

Proofreading source code

Build a random KDE git repository using kdesrc-build. Open the git repository in CLion. In CLion analyze the entire project. Fix some of the grammar issues. See https://www.youtube.com/watch?v=3gEAVvwLENc

Proofreading a KDE app handbook

Find a random KDE app https://apps.kde.org/ . E.g. KBreakOut https://apps.kde.org/kbreakout. In the right side of the web page > "Get help KBreakOut Handbook" > open the PDF version of the newest documentation for KBreakOut e.g. "Development (Frameworks 5) (PDF)". Select all of the text of the PDF e.g. if the PDF opens in Mozila Firefox right click on the content of the PDF > Select All > right click > Copy. Paste in a grammar checker and run a grammar check. E.g. create a new Google Doc, from the Google Docs main menu > Tools > Spelling and grammar > Spelling and grammar check. Or e.g. search on Google for "online grammar", open in new tabs dome of the online grammar checking web pages, in one of these pages paste the entire content of the PDF and run the grammar check. E.g. not all grammar checkers will detect missing commas.

Just running kdesrc-build should not create "Unstaged Changes" in the local clone of a KDE git repo

Build all the KDE git repositories using kdesrc-build. Run:
kdesrc-build
You should not see displayed the text:
* You had local changes to <ModuleName>, which have been re-applied.

In this case the issue is probably that the .gitignore file in the git repo is outdated.
E.g.
Install meld.
Let's say that kcalc is the git repo that reproduces this issue. You should have seen the text:
"* You had local changes to kcalc, which have been re-applied."

In konsole: I would run:
meld ~/kde/src/kconfig/.gitignore ~/kde/src/kcalc/.gitignore
In the diff viewer I can see that the last two lines in the file
~/kde/src/kconfig/.gitignore are new and do not exist yet in
~/kde/src/kcalc/.gitignore. I copy the new lines to ~/kde/src/kcalc/.gitignore
such that the two .gitignore files are identical.
Then I do a MR like https://invent.kde.org/graphics/kamera/-/merge_requests/5

C++

Fix g++ C++ compiler warning

In konsole:
CXX=g++ kdesrc-build kcalc --debug |& tee ~/buildoutput_gxx.txt

Open the file ~/buildoutput.txt in a text editor. E.g. kate.
Search for the string "warning: ". It should appear tens of thousands of times.
Pick a build warning that seems simple enough to you. Invest time to fix one build warning.
Test that your fix is OK.
E.g. for kcalc.
In konsole:
rm -rf ~/kde/build/kcalc
kdesrc-build kcalc --no-src --no-include-dependencies --debug
# Make sure there are no errors
cd ~/kde/build/kcalc
make test
# Make sure there are no errors

If everything is OK, fix a single g++ build warning,
do a single git commit and do a single MR.

Again, one MR should contain just one git commit.
And one git commit should contain only a single type of fixes (e.g. one type of fix),
with only handful of source code lines changed (e.g. only one line changed).

Fix clang++ C++ compiler warning

Do exactly as for g++ above.
Replace the first command line with:
CXX=clang++ kdesrc-build kcalc --debug |& tee ~/buildoutput_clangxx.txt

Fix Clang-Tidy static analysis issue

Build a KDE git repository using kdesrc-build. Open it in the IDE Qt Creator.
From Qt Creator main menu > Analyze > Clang-Tidy and Clazy... > press the Analyze button.

https://www.google.com/search?q=clang-tidy

Fix PVS-Studio static analysis issue

https://www.youtube.com/watch?v=NHwPhaIfrZ4
https://www.youtube.com/watch?v=XInpWKwkn4w

PVS-Studio can be evaluated for free for 7 days.
In order to evaluate for 30 days, you can use a promo code.
E.g. From the description of https://www.youtube.com/watch?v=vYW6TOwFK2M "Download PVS-Studio https://pvs-studio.com/en/pvs-studio/download/?promo=Cherno 
Enter promo code #Cherno in the message field to get a 30 day free trial instead of 7."

Download a file named e.g. pvs-studio-7.27.75620.346-x86_64.tgz

rm -r pvs-studio
mkdir pvs-studio
tar -zxvf pvs-studio*.tgz -C pvs-studio --strip-components=1
cd pvs-studio
./install.sh ~/.local
echo $PATH # Should contain "/home/username/.local/bin".
which pvs-studio-analyzer # Should say "/home/username/.local/bin/pvs-studio-analyzer".

# License. You have received an email with evaluation license key.
# Use the values from that email.
pvs-studio-analyzer credentials name_from_license_key_email license_from_license_key_email

Download the file https://invent.kde.org/nmariusp/kdesrc-build-extra/-/blob/master/pvsstudiorun.sh
to e.g. ~/kde. Edit the file as needed:
cd ~/kde/src/kdesrc-build
./kdesrc-build kconfig
./kdesrc-build kconfig --no-src --no-include-dependencies --debug --refresh-build

From the console output copy to a new text file the part:

"Running cmake targeting Kate - Ninja...
        cd /home/username/kde/build/kconfig

run_logged_command(): Module kconfig, Command: cmake -B . -S /home/username/kde/src/kconfig -G Kate - Ninja -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON -DCMAKE_BUILD_TYPE=Debug -DBUILD_WITH_QT6=ON -DCMAKE_CXX_FLAGS:STRING=-pipe -DCMAKE_INSTALL_PREFIX=/home/username/kde/usr -DCMAKE_PREFIX_PATH=/home/username/Qt/6.6.0/gcc_64
        Setting environment variable PATH to /home/username/kde/usr/bin:/home/username/Qt/6.6.0/gcc_64/bin:/home/username/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
        Setting environment variable QT_PLUGIN_PATH to /home/username/kde/usr/lib64/plugins:/home/username/kde/usr/lib/plugins
        Setting environment variable CMAKE_MODULE_PATH to /home/username/Qt/6.6.0/gcc_64/lib/cmake:/home/username/kde/usr/lib64/cmake:/home/username/kde/usr/lib/cmake
        Setting environment variable PKG_CONFIG_PATH to /home/username/kde/usr/lib/pkgconfig:/home/username/Qt/6.6.0/gcc_64/lib/pkgconfig
        Setting environment variable LD_LIBRARY_PATH to /home/username/kde/usr/lib:/home/username/Qt/6.6.0/gcc_64/lib
        Setting environment variable XDG_DATA_DIRS to /home/username/kde/usr/share
        Setting environment variable CMAKE_PREFIX_PATH to /home/username/Qt/6.6.0/gcc_64:/home/username/kde/usr
# kdesrc-build running: 'cmake' '-B' '.' '-S' '/home/username/kde/src/kconfig' '-G' 'Kate - Ninja' '-DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON' '-DCMAKE_BUILD_TYPE=Debug' '-DBUILD_WITH_QT6=ON' '-DCMAKE_CXX_FLAGS:STRING=-pipe' '-DCMAKE_INSTALL_PREFIX=/home/username/kde/usr' '-DCMAKE_PREFIX_PATH=/home/username/Qt/6.6.0/gcc_64'
# from directory: /home/username/kde/build/kconfig"
We will name this the "original part".

Convert this part to the following format:
"export QT_PLUGIN_PATH=$KDESRC_DIRECTORY_PATH/usr/lib64/plugins:$KDESRC_DIRECTORY_PATH/usr/lib/plugins
export CMAKE_MODULE_PATH=/home/username/Qt/6.6.0/gcc_64/lib/cmake:$KDESRC_DIRECTORY_PATH/usr/lib64/cmake:$KDESRC_DIRECTORY_PATH/usr/lib/cmake
export PKG_CONFIG_PATH=$KDESRC_DIRECTORY_PATH/usr/lib/pkgconfig:/home/username/Qt/6.6.0/gcc_64/lib/pkgconfig
export CMAKE_PREFIX_PATH=/home/username/Qt/6.6.0/gcc_64:$KDESRC_DIRECTORY_PATH/usr
export LD_LIBRARY_PATH=$KDESRC_DIRECTORY_PATH/usr/lib:/home/username/Qt/6.6.0/gcc_64/lib
export XDG_DATA_DIRS=$KDESRC_DIRECTORY_PATH/usr/share
export PATH=$KDESRC_DIRECTORY_PATH/usr/bin:/home/username/Qt/6.6.0/gcc_64/bin:/home/username/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

cmake -B . -S $KDESRC_DIRECTORY_PATH/src/$MODULE_NAME -G Kate\ -\ Ninja -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON -DCMAKE_BUILD_TYPE=Debug -DBUILD_WITH_QT6=ON -DCMAKE_CXX_FLAGS:STRING=-pipe -DCMAKE_INSTALL_PREFIX=$KDESRC_DIRECTORY_PATH/usr -DCMAKE_PREFIX_PATH=/home/username/Qt/6.6.0/gcc_64"
We will name this the "formatted part"

In the file ~/kde/pvsstudiorun.sh replace the part
"export CMAKE_MODULE_PATH=$KDESRC_DIRECTORY_PATH/usr/lib64/cmake:$KDESRC_DIRECTORY_PATH/usr/lib/cmake
export PKG_CONFIG_PATH=$KDESRC_DIRECTORY_PATH/usr/lib/pkgconfig
export CMAKE_PREFIX_PATH=$KDESRC_DIRECTORY_PATH/usr
export LD_LIBRARY_PATH=$KDESRC_DIRECTORY_PATH/usr/lib
export XDG_DATA_DIRS=$KDESRC_DIRECTORY_PATH/usr/share:/usr/share/plasma:/usr/local/share:/usr/share
export PATH=$KDESRC_DIRECTORY_PATH/usr/bin:$KDESRC_DIRECTORY_PATH/src/kdesrc-build:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

cmake -B . -S $KDESRC_DIRECTORY_PATH/src/$MODULE_NAME -G Unix\ Makefiles -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS:STRING=-pipe -DCMAKE_INSTALL_PREFIX=$KDESRC_DIRECTORY_PATH/usr"

with the "formatted part".

If you use ninja instead of "Unix Makefiles", replace
$PVSSTUDIO_BIN_PATH/pvs-studio-analyzer trace -- make -j `nproc`
with
$PVSSTUDIO_BIN_PATH/pvs-studio-analyzer trace -- ninja
.
chmod +x ~/kde/pvsstudiorun.sh
cd ~/kde
./pvsstudiorun.sh ~/kde/src/kconfig
# kate starts with the file ~/kde/build-pvs/kconfig/report.tasks open.
# Fix an issue, run the line "./pvsstudiorun.sh ~/kde/src/kconfig"
# again to confirm that the issue has been fixed.

Open in the IDE Qt Creator ~/kde/src/kconfig. See https://develop.kde.org/docs/getting-started/building/ide/qt-creator/
From the Qt Creator main menu > File > Open File or Project > ~/kde/build-pvs/kconfig/report.tasks
The file ~/kde/build-pvs/kconfig/report.tasks will be shown in the "Issues Alt+1" tool window.

Fix Cppcheck static analysis issue

https://en.wikipedia.org/wiki/Cppcheck
https://www.youtube.com/watch?v=5OYvQ4Mi_1I
https://www.youtube.com/watch?v=1TSeSVDI3_s

Qt Creator has a plugin for cppcheck.
Build a KDE git repository using kdesrc-build. Open it in the IDE Qt Creator.
From Qt Creator main menu > Help > About Plugins > Code Analyzer > enable Cppcheck (experimental).
Restart Qt Creator. From Qt Creator main menu > Analyze > Cppcheck... > make sure that the content of the edit box "Custom arguments:" is "--inline-suppr" > press the Analyze button.

If the developer wants, the developer can disable the cppcheck warning for a source code line. 
The man page for cppcheck says "--inline-suppr
Enable inline suppressions. Use them by placing comments in the form:
// cppcheck-suppress <CppcheckErrorID>
before the line to suppress.".

E.g. in the application kalk:
// cppcheck-suppress duplicateExpression
KNumber::NegInfinity / KNumber::NegInfinity,
Disables the cppcheck warning "kalk/knumber/tests/knumbertest.cpp:678: Same expression on both sides of '/'.".

After you have fixed all of the cppcheck warnings that you can. After you have suppressed in source code using comments all the cppcheck warnings that the developer wants to be suppressed. Create a cppcheck command line that returns success (exit status zero). And do a Merge Request such that the Continuous Integration (CI) will make sure that cppcheck returns success. E.g. https://invent.kde.org/plasma-mobile/kalk/-/merge_requests/43

Fix KDE clazy static analysis issue

Build a KDE git repository using kdesrc-build. Open it in the IDE Qt Creator.
From Qt Creator main menu > Analyze > Clang-Tidy and Clazy... > press the Analyze button.

https://www.youtube.com/watch?v=Z6MENrBRYJI

Fix static analysis issue using Allen Winter's krazy

Install krazy:

# Read https://github.com/Krazy-collection/krazy/blob/master/Install.txt
# Set up kdesrc-build using the kdesrc-build setup procedure.
kdesrc-build frameworks

mkdir -p ~/kde/misc && cd ~/kde/misc
git clone https://github.com/Krazy-collection/krazy.git
cd krazy
# Install the packages mentioned in chapter "Requirements" of https://github.com/Krazy-collection/krazy/blob/master/Install.txt . E.g.:
# sudo apt install libjson-perl libyaml-perl

# If you have installed Qt using kdesrc-build, prepend ~/kde/usr to some environment variables. E.g.:
# source ~/kde/build/kconfig/prefix.sh
./install.sh ~/.local
# Make sure "~/.local/bin" is in your $PATH environment variable.
echo $PATH
# Should contain the directory "~/.local/bin".
which krazy2
# Should say: "~/.local/bin/krazy2"
# Read the help:
krazy2 --help
# Test
krazy2 ~/kde/src/kconfig/src/core/*.{cpp,h}

Build a KDE git repository using kdesrc-build. Run krazy on the source code files of that KDE git repository:

kdesrc-build kconfig
krazy2 --brief --check-sets c++,qt5,kde5,foss --explain ~/kde/src/kconfig/src/core/*.{cpp,h}
# Says:
#Check for spelling errors [spelling]... 2 issues found
#        ~/kde/src/kconfig/src/core/kauthorized.h: line#45[of of] (1)
#        ~/kde/src/kconfig/src/core/kcoreconfigskeleton.h: line#805[for for] (1)

# The qt5 and kde5 check-sets also work for Qt6 and KDE Frameworks 6.

# Go over all of the source code files.
cd ~/kde/src/kconfig
find . -type f -name "*.cpp" -print -exec bash -c  'echo "{}"; krazy2 --brief --check-sets c++,qt5,kde5,foss --explain "{}" ' \; |& tee ~/a.txt

Use the new Qt signal slot syntax

https://wiki.qt.io/New_Signal_Slot_Syntax

Fix deprecation issue

E.g. kDebug, kWarning and other symbols from ~/kde/usr/include/KF5/KDELibs4Support/kdebug.h are deprecated. Replace with e.g. the symbols in the family of qDebug from ~/kde/usr/include/QtCore/qlogging.h and ~/kde/usr/include/QtCore/qdebug.h .

E.g. run kdesrc-build without parameters, this will git clone and build all KDE git repositories. Search in ~/kde/src (i.e. in all the KDE git repositories) using e.g. VS Code for a deprecated symbol. You find an affected source code file in the git repository X. Open that git repository correctly in Qt Creator. Make sure that the deprecated symbol really is the one you thought it is. Replace the deprecated symbol. Build, test, git commit, MR.

Use C++ defines

Some of the defines that you can use in order to generate build/compiler errors or warnings: QT_USE_QSTRINGBUILDER, QT_STRICT_ITERATORS, QT_NO_URL_CAST_FROM_STRING, QT_NO_CAST_FROM_BYTEARRAY, QT_NO_SIGNALS_SLOTS_KEYWORDS, QT_USE_FAST_OPERATOR_PLUS, QT_NO_URL_CAST_FROM_STRING, QT_NO_CAST_TO_ASCII, QT_NO_CAST_FROM_ASCII, QT_DISABLE_DEPRECATED_BEFORE=0x050900.

E.g. have in the kdesrc-buildrc file in the global section:

cmake-options -DCMAKE_BUILD_TYPE=Debug -DQT_NO_CAST_FROM_ASCII=ON -DQT_NO_CAST_TO_ASCII=ON

Some KDE git repositories undefine some of the above defines. E.g. https://invent.kde.org/system/dolphin/-/blob/master/src/CMakeLists.txt?ref_type=heads#L8 says:

remove_definitions(
    -DQT_NO_CAST_FROM_BYTEARRAY
    -DQT_NO_CAST_FROM_ASCII
    -DQT_NO_CAST_TO_ASCII
)

QML

qmllint

# Get the source code of all of the KDE git repositories using kdesrc-build:
kdesrc-build --src-only
cd ~/kde/src
# As per https://www.kdab.com/kdab-contributions-qt-5-4-qmllint/
find . -type f -name "*.qml" -exec qmllint \{\} +
# Make sure that the list of warnings returned today is not longer than the list of warnings returned in a previous day.

Note: Once the qmllint installed from you Linux distribution's packages has the feature "You can now ignore individual warnings by adding "// qmllint disable" in the line causing it. You may also specify one or more warning type to ignore ("// qmllint disable warningtype1 warningtype2...") which is preferable. This can also be done for entire blocks of code by using "// qmllint disable" in an empty line and ending it with "// qmllint enable"" https://codereview.qt-project.org/c/qt/qtdeclarative/+/351372/6 . Then we will be able to add comments in the "*.qml" files that have qmllint warnings. The end goal is that running qmllint on all of the "*.qml" files from all of the KDE git repositories should not show any qmllint warnings.

qmlscene

# This is an advanced topic.
# Get the source code of all of the KDE git repositories using kdesrc-build:
kdesrc-build --src-only
cd ~/kde/src
find . -type f -name "*.qml" -print -exec bash -c  'echo "qmlscene {}"; qmlscene "{}" --quit' \; |& tee ~/a.txt
kate ~/a.txt &
# For now, ignore the errors of type:
# module "X" is not installed
# ReferenceError: Y is not defined
# Make sure that the list of warnings returned today is not longer than the list of warnings returned in a previous day.

CMake

cmakelint

Install https://github.com/cmake-lint/cmake-lint .

Set up kdesrc-build. Choose a KDE git repository, e.g. kconfig.

kdesrc-build kconfig
cd ~/kde/src/kconfig
for i in `find . -type f -name "CMakeLists.txt"`; do cmakelint "$i"; done &> ~/a.txt
kate ~/a.txt &

for i in `find . -type f -name "*.cmake"`; do cmakelint "$i"; done &> ~/b.txt
kate ~/b.txt &

Call the cmake_minimum_required() command at the beginning of the top-level CMakeLists.txt file

* https://cmake.org/cmake/help/latest/command/cmake_minimum_required.html :
"Note Call the cmake_minimum_required() command at the beginning of the
top-level CMakeLists.txt file even before calling the project() command.
It is important to establish version and policy settings before invoking
other commands whose behavior they may affect. See also policy CMP0000."

Find an affected KDE git repo where in the top level CMakeLists.txt before
cmake_minimum_required() exist non empty lines, no comment lines,
but lines that contain CMake source code.
Do a MR like https://invent.kde.org/graphics/kolourpaint/-/merge_requests/23

Example:
I install Microsoft Visual Studio Code and I make sure that "code" is in $PATH.
I build all KDE git repos:
kdesrc-build
without parameters.
In ~/.config/kdesrc-buildrc I have:
directory-layout invent
In konsole:
cd ~/kde/src
code . # This will start VS Code.
In VS Code main menu > View > Search Ctrl+Shift+F. In the Search field write:
cmake_minimum_required
in the field "files to include" write:
CMakeLists.txt
Press F4 one hundred times. It will go through all of the lines that contain
"cmake_minimum_required" in all of the files named "CMakeLists.txt".
You probably do not want to edit the CMakeLists.txt file from subdirectories named
like 3rdparty. These directories are a non KDE project, which has its upstream
git repo outside invent.kde.org. Fix the issues in third party libraries in their
upstream git repo.

KDE wiki

You should probably not edit old or archived wiki pages. E.g. https://community.kde.org/Schedules/Applications/17.04_Feature_Plan Do not edit wiki pages about an event from 10 years ago, e.g. https://community.kde.org/KDE_PIM/Meetings/Osnabrueck_4. Do not edit wiki pages about old technologies e.g. maemo, QtWebKit, KDE 4, Qt4, QBS etc.

Spell check and grammar check a random KDE wiki page

E.g.
Create a new Google Doc named “SpellCheck”.
In the web browser:
https://community.kde.org/index.php?title=Special:Random
takes you to:
https://community.kde.org/Get_Involved Ctrl+A Ctrl+C.

In the Google Doc: Ctrl+Shift+V. From the Google Doc main menu > Tools >
Spelling and grammar > Spelling and grammar check. It says that we should replace:
"KDE's Quality Assurance team tests pre-release software and proposed changed to make sure that everything works properly!"
with:
"KDE's Quality Assurance team tests pre-release software and proposes changes to make sure that everything works properly!"
In the web browser: edit the KDE wiki page to fix the spelling or grammar error.

In a random KDE wiki page, URL links should work correctly

E.g.
In the web browser:
https://community.kde.org/index.php?title=Special:Random
takes you to:
https://community.kde.org/Incubator/Projects/Rkward
you click on the URL:
"Its features can be extended by plugins, and it's all free software (Above information from
the current Rkward homepage." http://rkward.sourceforge.net/wiki/Main_Page
This takes you to:
https://rkward.kde.org/Main_Page
which is a web page that does not exist.

Edit the KDE wiki such that you replace the invalid URL
"http://rkward.sourceforge.net/wiki/Main_Page" with a valid URL.
Which in this case is the canonical homepage of the project rkward.
I.e. https://apps.kde.org/rkward/ .
This URL is probably better than the other possibility: https://rkward.kde.org/ .

In a random KDE wiki page, the wiki markup should be correct

Learn wikipedia/mediawiki wiki markup syntax. E.g. https://www.mediawiki.org/wiki/Help:Formatting , https://www.mediawiki.org/wiki/Cheatsheet

E.g.
In the web browser:
https://community.kde.org/index.php?title=Special:Random
takes you to:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging
You should be logged in. You edit the page (in the left hand side of the page Actions > Edit).

You see that "=" is used instead of "==". https://www.mediawiki.org/wiki/Help:Formatting says "Section formatting – only at the beginning of the line ... == Level 2 == ... Skip Level 1, it is page name level.". So you replace all "=" with "==". Make sure that the Table of Contents stays the same. 
E.g. https://community.kde.org/index.php?title=Guidelines_and_HOWTOs%2FBug_triaging&type=revision&diff=95496&oldid=95495

KDE Craft

Besides kdesrc-build. KDE has another tool that can build KDE git repos: KDE Craft.
https://community.kde.org/Craft

E.g. choose a KDE git repo. E.g. kcalc.
Choose one of the operating systems supported by KDE Craft.
One of Microsoft Windows, Apple macOS, Linux or FreeBSD. E.g. Linux.
Create a Linux VM, install KDE Craft in this VM.
In konsole:
craft kcalc
Run the newly built/downloaded and installed kcalc.

Run executable using a run time analyzer

This is neither easy, nor suitable for beginners.

Build a KDE git repo that is not a framework or a library.
I.e. build a KDE app.
Make sure that you have kdesrc-build configured to build using
CMake build configuration "Debug".
I.e. in ~/.config/kdesrc-buildrc I have:
cmake-options -DCMAKE_BUILD_TYPE=Debug

E.g. build kcalc:
In konsole:
kdesrc-build kcalc
Then run kcalc under valgrind.

If valgrind says that there is an issue.
And if the issue is not in Mesa or in Qt.
But the issue is in one of the KDE git repos, e.g. a memory leak.
valgrind will say the line where the leak occurs.

Remove old technologies

E.g. khtml ("-khtml-border-radius: 7px;"), the Java web browser plugin, the Flash web browser plugin, Netscape plugin API (npapi) web browser plugins, instant messaging protocols that do not exist anymore e.g. AIM, ICQ, Yahoo etc. Mentions of old versions of Opera web browser which did not use the HTML rendering engine from Google Chrome. win 32 movie codecs.

Non standard technologies since the standard technologies are supported by the major software products for ten years e.g. "-moz-border-radius: 2px; -webkit-border-radius: 2px;", maybe even "#pragma once".

State of the art

• AppStream. Rename files named like org.kde.haruna.appdata.xml to org.kde.haruna.metainfo.xml. See https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#spec-component-location

• AppStream. All KDE git repositories for GUI apps should contain at least one appstream org.kde.<appname>.metainfo.xml file.

• Make sure the home page of the KDE app https://apps.kde.org/<appname> is up to date. E.g. should contain a screenshot of the app, not a screenshot of the manual, should not contain a link to https://userbase.kde.org, should contain a link to the app's Handbook. Make sure that the appstream "Install on Linux" URL (e.g. "appstream://org.kde.kmag.desktop") works correctly.

• In an automated fashion, make sure that all of the appdata files have valid and recent "Releases" information.

• Do not use URLs that do not work.

• Do not use URLs that redirect to a better URL. Use the better URL instead. E.g. https://apps.kde.org/<appname> not one of the URLs that redirect to https://apps.kde.org/<appname>.

• In CMakeLists.txt, use "find_package(KF6 ${KF_MIN_VERSION} REQUIRED COMPONENTS CoreAddons Config" instead of "find_package(KF6Config) set_package_properties(KF6Config PROPERTIES TYPE REQUIRED)".

• Validate all appstream files using a command line like "appstreamcli validate org.kde.kmag.appdata.xml".

cd ~/kde/src
for i in `find . -type f -name "*.appdata.xml"`; do appstreamcli validate --explain "$i"; done &> ~/a.txt
for i in `find . -type f -name "*.metainfo.xml"`; do appstreamcli validate --explain "$i"; done &>> ~/a.txt
kate ~/a.txt &

This is the list of appstream issues as of 2023.12.28 https://drive.google.com/file/d/1Dl9ZYVbihARYa8z_2xzTzd-j0MW-6sTA .

Note: do not look at the translated strings. If you want to improve the translated strings, please ask for help from the KDE translators team.

How to install kde-builder

Qt 6 installed using Qt online installer

The homepage of the Qt Framework is https://www.qt.io . Go to this web page, create an online account. https://www.qt.io/download-open-source > "Download the Qt Online Installer" > Linux > "Qt Online Installer for Linux (64-bit)" > download a file named e.g. qt-unified-linux-x64-4.6.1-online.run into the directory e.g. "~/Downloads".

ls -la ~/Downloads # The downloaded file needs to hace the "executable" chmod bit set.
chmod +x ~/Downloads/qt-unified-linux-x64-4.6.1-online.run
~/Downloads/qt-unified-linux-x64-4.6.1-online.run

Login using your Qt online account. Next > check the checkbox "I have read and agree to the terms and conditions of using OpenSource Qt", check the checkbox "I'm an individual and do not use Qt for any company" > Next > Next > enable "Help us improve" > Next > Custom installation, notice that the install directory is "~/Qt" > Next. Install the latest version of Qt6 and the latest version of the Qt Creator integrated development environment (IDE). There are some Qt6 components that are not used by KDE and can be left out when installing Qt6 e.g. WebAssembly, Android, Sources, Qt Quick 3D, Qt 3D, "Quick: 3D Physics", "Qt debug Information Files".

In the KDE Plasma app launcher you now have the application "Qt Maintenance Tool".

Set up kde-builder from scratch as usual.

Edit the file kdesrc-buildrc to look like:

global
...
    qt-install-dir  ~/Qt/6.6.0/gcc_64 # Where to install Qt6 if kdesrc-build supplies it
    libname lib
...
end global

Make gpgme build:

sudo su
mkdir -p /home/qt/work
chown -R username:username /home/qt/work
ln -s /home/username/Qt/6.6.0/gcc_64 /home/qt/work/install
ls -la /home/qt/work

More

How to write the entire verbose STDOUT and STDERR of kdesrc-build to a file

script -eq -c "kdesrc-build kconfig --no-src --no-include-dependencies --refresh-build --debug" ~/a.txt ;  sed -i $'s/\033\[[0-9]\+m//g' ~/a.txt

The sed part removes the terminal ANSI color escape codes.

script -eq -c "command" ~/a.txt is better than command |& tee ~/a.txt because kdesrc-build behaves differently if it is run in a user interactive terminal session (isatty).

If using tee, part of the output of kdesrc-build will not be written to file. E.g. the output of the cmake step, the final part of the make -j step, the final part of the make install step.