Setup

• Clone microsoft/vscode

• Run npm i at /, this will install

  • Dependencies for /extension/css-language-features/

  • Dependencies for /extension/css-language-features/server/

  • devDependencies such as gulp

• Open /extensions/css-language-features/ as the workspace in VS Code

• In /extensions/css-language-features/ run npm run compile(or npm run watch) to build the client and server

• Run the Launch Extension debug target in the Debug View. This will:

  • Launch a new VS Code instance with the css-language-features extension loaded

• Open a .css file to activate the extension. The extension will start the CSS language server process.

• Add "css.trace.server": "verbose" to the settings to observe the communication between client and server in the CSS Language Server output.

• Debug the extension and the language server client by setting breakpoints incss-language-features/client/

• Debug the language server process by using Attach to Node Process command in the VS Code window opened on css-language-features.

  • Pick the process that contains cssServerMain in the command line. Hover over code-insiders resp code processes to see the full process command line.

  • Set breakpoints in css-language-features/server/

• Run Reload Window command in the launched instance to reload the extension

Contribute to vscode-css-languageservice

microsoft/vscode-css-languageservice contains the language smarts for CSS/SCSS/Less. This extension wraps the css language service into a Language Server for VS Code. If you want to fix CSS/SCSS/Less issues or make improvements, you should make changes at microsoft/vscode-css-languageservice.

However, within this extension, you can run a development version of vscode-css-languageservice to debug code or test language features interactively:

Linking vscode-css-languageservice in css-language-features/server/

• Clone microsoft/vscode-css-languageservice

• Run npm i in vscode-css-languageservice

• Run npm link in vscode-css-languageservice. This will compile and link vscode-css-languageservice

• In css-language-features/server/, run npm link vscode-css-languageservice

Testing the development version of vscode-css-languageservice

• Open both vscode-css-languageservice and this extension in a single workspace with multi-root workspace feature

• Run npm run watch in vscode-css-languageservice to recompile the extension whenever it changes

• Run npm run watch at css-language-features/server/ to recompile this extension with the linked version of vscode-css-languageservice

• Make some changes in vscode-css-languageservice

• Now when you run Launch Extension debug target, the launched instance will use your development version of vscode-css-languageservice. You can interactively test the language features.