Kotlin Programming Language
Welcome to Kotlin!
It is an open-source, statically typed programming language supported and developed by JetBrains and open-source contributors.
Some handy links:
Kotlin Multiplatform capabilities
Support for multiplatform programming is one of Kotlin’s key benefits. It reduces time spent writing and maintaining the same code for different platforms while retaining the flexibility and benefits of native programming.
Editing Kotlin
Build environment requirements
This repository is using Gradle toolchains feature
to select and auto-provision required JDKs from AdoptOpenJdk project.
Alternatively, it is still possible to only provide required JDKs via environment variables
(see gradle.properties for supported variable names). To ensure Gradle uses only JDKs
from environmental variables - disable Gradle toolchain auto-detection by passing -Porg.gradle.java.installations.auto-detect=false
option
(or put it into $GRADLE_USER_HOME/gradle.properties
).
On Windows you might need to add long paths setting to the repo:
git config core.longpaths true
Building
The project is built with Gradle. Run Gradle to build the project and to run the tests
using the following command on Unix/macOS:
./gradlew <tasks-and-options>
or the following command on Windows:
gradlew <tasks-and-options>
On the first project configuration gradle will download and setup the dependencies on
intellij-core
is a part of command line compiler and contains only necessary APIs.idea-full
is a full blown IntelliJ IDEA Community Edition to be used in the plugin module.
These dependencies are quite large, so depending on the quality of your internet connection
you might face timeouts getting them. In this case, you can increase timeout by specifying the following
command line parameters on the first run:
./gradlew -Dhttp.socketTimeout=60000 -Dhttp.connectionTimeout=60000
Important gradle tasks
clean
- clean build resultsdist
- assembles the compiler distribution into dist/kotlinc/
folderinstall
- build and install all public artifacts into local maven repositorycoreLibsTest
- build and run stdlib, reflect and kotlin-test testsgradlePluginTest
- build and run gradle plugin testscompilerTest
- build and run all compiler tests
To reproduce TeamCity build use -Pteamcity=true
flag. Local builds don't run proguard and have jar compression disabled by default.
OPTIONAL: Some artifacts, mainly Maven plugin ones, are built separately with Maven.
Refer to libraries/ReadMe.md for details.
To build Kotlin/Native, see
kotlin-native/README.md.
Working with the project in IntelliJ IDEA
It is recommended to use the latest released version of Intellij IDEA (Community or Ultimate Edition). You can download IntelliJ IDEA here.
After cloning the project, import the project in IntelliJ by choosing the project directory in the Open project dialog.
For handy work with compiler tests it's recommended to use
Kotlin Compiler Test Helper
Dependency verification
We have a dependencies verification feature enabled in the
repository for all Gradle builds. Gradle will check hashes (md5 and sha256) of used dependencies and will fail builds with
Dependency verification failed
errors when local artifacts are absent or have different hashes listed in the
verification-metadata.xml file.
It's expected that verification-metadata.xml
should only be updated with the commits that modify the build. There are some tips how
to perform such updates:
- Delete
components
section of verification-metadata.xml
to avoid stockpiling of old unused dependencies. You may use the following command:
sed -i '' -e '/<components>/,/<\/components>/d' gradle/verification-metadata.xml
sed -i -e '/<components>/,/<\/components>/d' gradle/verification-metadata.xml
- Re-generate dependencies with Gradle's
--write-verification-metadata
command (verify update relates to your changes)
./gradlew --write-verification-metadata sha256,md5 -Pkotlin.native.enabled=true resolveDependencies
resolveDependencies
task resolves dependencies for all platforms including dependencies downloaded by plugins.
You can also use ./scripts/update-verification-metadata.sh
script which includes both of these steps
Keep in mind:
- If you’re adding a dependency with OS mentioned in an artifact name (
darwin
, mac
, osx
, linux
, windows
), remember to add them to
implicitDependencies
configuration or update resolveDependencies
task if needed. resolveDependencies
should resolve all dependencies
including dependencies for different platforms. - If you have a
local.properties
file in your Kotlin project folder, make sure that it doesn't contain kotlin.native.enabled=false
.
Otherwise, native-only dependencies may not be added to the verification metadata. This is because local.properties
has higher
precedence than the -Pkotlin.native.enabled=true
specified in the Gradle command.
Using -dev versions
We publish -dev
versions frequently.
For -dev
versions you can use the list of available versions and include this maven repository:
maven("https://maven.pkg.jetbrains.space/kotlin/p/kotlin/bootstrap")
License
Kotlin is distributed under the terms of the Apache License (Version 2.0). See license folder for details.
Contributing
Please be sure to review Kotlin's contributing guidelines to learn how to help the project.