Checker Framework Language Server

This is a language server for the Checker Framework, which makes the Checker Framework usable by all editors/IDEs that support the Language Server Protocol. It is implemented with LSP4J

How to Build

./gradlew assemble

will generate build/libs/checker-framework-languageserver-all.jar.

How to Use

The language server can be launched in the command line interface, although it's not intended to be launched manually. Normally, you would want to install a dedicated plugin that supports LSP for your editor, and then connect this language server to that plugin via standard input/output. Input and output are both in the LSP format.

Note that this project only supports running with Java 8.

java \
    -cp /path/to/checker-framework-languageserver-all.jar:/path/to/checker-framework/checker/dist/checker.jar \
    org.checkerframework.languageserver.ServerMain \
    --frameworkPath /path/to/checker-framework \
    --checkers org.checkerframework.checker.nullness.NullnessChecker \
    --checkers some.other.checker \
    --commandLineOptions command_line_opt_1 \
    --commandLineOptions command_line_opt_2

Editor Support

VS Code

Please see eisopux/checker-framework-vscode.

IntelliJ IDEA

This language server can be used directly with the help of gtache/intellij-lsp. Provide a raw command to it to launch this language server and it's done. Please also refer to eisopux/checker-framework-idea.

Eclipse

Please see eisopux/checker-framework-eclipse.

Notes for Development

As LSP4J lacks documentation, it's suggested that the developer of this project uses an IDE supporting auto-completion so the methods/interfaces/classes of LSP4J can be easily inspected to figure out what is actually given/expected.

To format the source code, run $ ./gradlew spotlessApply.

Dependency on Checker Framework

This project has a dependency on the Checker Framework, but it's only on org.checkerframework.framework.util.CheckerMain, which is used by CheckExecutor to generate the arguments for launching the Checker Framework properly. Therefore it's not necessary to update this dependency very often; it only needs to be updated if in a future version the interface of CheckerMain changes.

The eisopux/checker-framework-languageserver-downloader project allows plugins to automatically download a Checker Framework release.

Using a locally-built Checker Framework language server

Editor plugins auto-download the Checker Framework language server when they start. If you want to run with a locally-built language server instead:

• build the language server locally ./gradlew assemble;
• consult the documentation for the editor plugin to determine where it looks for the Checker Framework language server;
• copy the build/libs/checker-framework-languageserver-all.jar file to that directory.

More information

The report Checker Framework Integration for Editors and Integrated Development Environments (IDEs) based on the Language Server Protocol (LSP) contains more technical details.

Acknowledgements

• checkerframework-lsp
• vscode-languageserver-java-example