feat(oxlint): add --lsp flag to run the language server (#15611)

closes #15038 and #12251

> This PR adds a --lsp flag to the oxlint command-line tool that starts the language server directly, allowing for a unified binary that can function as both a linter and a language server. This addresses the need for a simpler deployment model where a single oxlint binary can be used in different modes.

Author: Sysix

.github/workflows/ci_vscode.yml

@@ -17,6 +17,7 @@ on:
     paths:
       - "pnpm-lock.yaml"
       - "crates/oxc_language_server/**"
+      - "apps/oxlint/src/lsp.rs"
       - "editors/vscode/**"
       - ".github/workflows/ci_vscode.yml"
 
@@ -45,6 +46,10 @@ jobs:
         working-directory: editors/vscode
         run: pnpm run server:build:debug
 
+      - name: Build oxlint (with napi)
+        working-directory: editors/vscode
+        run: pnpm run oxlint:build:debug
+
       - name: Compile VSCode
         working-directory: editors/vscode
         run: pnpm run compile

Cargo.lock

@@ -133,6 +133,7 @@ oxc_traverse = { version = "0.97.0", path = "crates/oxc_traverse" } # AST traver
 
 # publish = false
 oxc_formatter = { path = "crates/oxc_formatter" } # Code formatting
+oxc_language_server = { path = "crates/oxc_language_server" } # Language server
 oxc_linter = { path = "crates/oxc_linter" } # Linting engine
 oxc_macros = { path = "crates/oxc_macros" } # Proc macros
 oxc_tasks_common = { path = "tasks/common" } # Task utilities

Cargo.toml

@@ -29,6 +29,7 @@ doctest = false
 [dependencies]
 oxc_allocator = { workspace = true, features = ["fixed_size"] }
 oxc_diagnostics = { workspace = true }
+oxc_language_server = { workspace = true }
 oxc_linter = { workspace = true }
 oxc_span = { workspace = true }
 
@@ -44,7 +45,7 @@ serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 simdutf8 = { workspace = true }
 tempfile = { workspace = true }
-tokio = { workspace = true, features = ["rt-multi-thread"] }
+tokio = { workspace = true, features = ["rt-multi-thread", "io-std", "macros"] }
 tracing-subscriber = { workspace = true, features = [] } # Omit the `regex` feature
 
 [target.'cfg(not(any(target_os = "linux", target_os = "freebsd", target_arch = "arm", target_family = "wasm")))'.dependencies]

apps/oxlint/Cargo.toml

@@ -39,6 +39,10 @@ pub struct LintCommand {
     #[bpaf(long("rules"), switch, hide_usage)]
     pub list_rules: bool,
 
+    /// Start the language server
+    #[bpaf(long("lsp"), switch, hide_usage)]
+    pub lsp: bool,
+
     #[bpaf(external)]
     pub misc_options: MiscOptions,
 

apps/oxlint/src/command/lint.rs

@@ -4,6 +4,7 @@
 mod command;
 mod init;
 mod lint;
+mod lsp;
 mod output_formatter;
 mod result;
 mod walk;
@@ -13,7 +14,7 @@ mod tester;
 
 /// Re-exported CLI-related items for use in `tasks/website`.
 pub mod cli {
-    pub use super::{command::*, init::*, lint::CliRunner, result::CliRunResult};
+    pub use super::{command::*, init::*, lint::CliRunner, lsp::run_lsp, result::CliRunResult};
 }
 
 // Only include code to run linter when the `napi` feature is enabled.

apps/oxlint/src/lib.rs

@@ -0,0 +1,4 @@
+/// Run the language server
+pub async fn run_lsp() {
+    oxc_language_server::run_server(vec![Box::new(oxc_language_server::ServerLinterBuilder)]).await;
+}

apps/oxlint/src/lsp.rs

@@ -1,14 +1,21 @@
 use std::io::BufWriter;
 
-use oxlint::cli::{CliRunResult, CliRunner, init_miette, init_tracing, lint_command};
-
-fn main() -> CliRunResult {
-    init_tracing();
-    init_miette();
+use oxlint::cli::{CliRunResult, CliRunner, init_miette, init_tracing, lint_command, run_lsp};
 
+#[tokio::main]
+async fn main() -> CliRunResult {
     // Parse command line arguments from std::env::args()
     let command = lint_command().run();
 
+    // If --lsp flag is set, run the language server
+    if command.lsp {
+        run_lsp().await;
+        return CliRunResult::LintSucceeded;
+    }
+
+    init_tracing();
+    init_miette();
+
     command.handle_threads();
 
     // stdio is blocked by LineWriter, use a BufWriter to reduce syscalls.

apps/oxlint/src/main.rs

@@ -64,34 +64,42 @@ pub type JsLintFileCb = ThreadsafeFunction<
 #[allow(clippy::trailing_empty_array, clippy::unused_async)] // https://github.com/napi-rs/napi-rs/issues/2758
 #[napi]
 pub async fn lint(args: Vec<String>, load_plugin: JsLoadPluginCb, lint_file: JsLintFileCb) -> bool {
-    lint_impl(args, load_plugin, lint_file).report() == ExitCode::SUCCESS
+    lint_impl(args, load_plugin, lint_file).await.report() == ExitCode::SUCCESS
 }
 
 /// Run the linter.
-fn lint_impl(
+async fn lint_impl(
     args: Vec<String>,
     load_plugin: JsLoadPluginCb,
     lint_file: JsLintFileCb,
 ) -> CliRunResult {
-    init_tracing();
-    init_miette();
-
     // Convert String args to OsString for compatibility with bpaf
     let args: Vec<std::ffi::OsString> = args.into_iter().map(std::ffi::OsString::from).collect();
 
-    let cmd = crate::cli::lint_command();
-    let command = match cmd.run_inner(&*args) {
-        Ok(cmd) => cmd,
-        Err(e) => {
-            e.print_message(100);
-            return if e.exit_code() == 0 {
-                CliRunResult::LintSucceeded
-            } else {
-                CliRunResult::InvalidOptionConfig
-            };
+    let command = {
+        let cmd = crate::cli::lint_command();
+        match cmd.run_inner(&*args) {
+            Ok(cmd) => cmd,
+            Err(e) => {
+                e.print_message(100);
+                return if e.exit_code() == 0 {
+                    CliRunResult::LintSucceeded
+                } else {
+                    CliRunResult::InvalidOptionConfig
+                };
+            }
         }
     };
 
+    // If --lsp flag is set, run the language server
+    if command.lsp {
+        crate::lsp::run_lsp().await;
+        return CliRunResult::LintSucceeded;
+    }
+
+    init_tracing();
+    init_miette();
+
     command.handle_threads();
 
     // JS plugins are only supported on 64-bit little-endian platforms at present

apps/oxlint/src/run.rs

@@ -16,11 +16,12 @@ const ext = process.platform === 'win32' ? '.exe' : '';
 
 export default defineConfig({
   tests: [
+    // Single-folder workspace tests
     {
       files: 'out/**/*.spec.js',
       workspaceFolder: './test_workspace',
       launchArgs: [
-        // This disables all extensions except the one being testing
+        // This disables all extensions except the one being tested
         '--disable-extensions',
       ],
       env: {
@@ -31,11 +32,12 @@ export default defineConfig({
         timeout: 10_000,
       },
     },
+    // Multi-root workspace tests
     {
       files: 'out/**/*.spec.js',
       workspaceFolder: multiRootWorkspaceFile,
       launchArgs: [
-        // This disables all extensions except the one being testing
+        // This disables all extensions except the one being tested
         '--disable-extensions',
       ],
       env: {
@@ -46,5 +48,23 @@ export default defineConfig({
         timeout: 10_000,
       },
     },
+    // Oxlint --lsp tests
+    {
+      files: 'out/**/*.spec.js',
+      workspaceFolder: './test_workspace',
+      launchArgs: [
+        // This disables all extensions except the one being tested
+        '--disable-extensions',
+      ],
+      env: {
+        SINGLE_FOLDER_WORKSPACE: 'true',
+        OXLINT_LSP_TEST: 'true',
+        SERVER_PATH_DEV: path.resolve(import.meta.dirname, `../../apps/oxlint/dist/cli.js`),
+        SKIP_FORMATTER_TEST: 'true',
+      },
+      mocha: {
+        timeout: 10_000,
+      },
+    },
   ],
 });