feat: auto-restart tools when dependency lock file changes

.gitignore

@@ -17,3 +17,4 @@ icon.png
 
 # Rust
 vscode_docs/target/
+package-lock.json

client/extension.ts

@@ -3,6 +3,7 @@ import { commands, ExtensionContext, LogOutputChannel, window, workspace } from
 import { copyDebugCommand, OxcCommands } from "./commands";
 import { ConfigService } from "./ConfigService";
 import StatusBarItemHandler from "./StatusBarItemHandler";
+import { BinaryWatcher } from "./tools/BinaryWatcher";
 import Formatter from "./tools/formatter";
 import Linter from "./tools/linter";
 import ToolInterface from "./tools/ToolInterface";
@@ -128,6 +129,27 @@ export async function activate(context: ExtensionContext) {
 
   // Finally show the status bar item.
   statusBarItemHandler.show();
+
+  // Watch for lock file changes (e.g. after npm/pnpm/yarn/bun install) so that
+  // tools are restarted automatically without requiring a VS Code restart.
+  const createBinaryWatcher = (
+    toolClass: typeof Linter | typeof Formatter,
+    binaryName: string,
+    outputChannel: LogOutputChannel,
+  ) => {
+    const tool = tools.find((t) => t instanceof toolClass);
+    if (tool) {
+      const binary = binaryPaths[tools.indexOf(tool)];
+      context.subscriptions.push(
+        new BinaryWatcher(binary, binaryName, outputChannel, () =>
+          restartTool(tool, outputChannel),
+        ),
+      );
+    }
+  };
+
+  createBinaryWatcher(Linter, "oxlint", outputChannelLint);
+  createBinaryWatcher(Formatter, "oxfmt", outputChannelFormat);
 }
 
 export async function deactivate(): Promise<void> {

client/findBinary.ts

@@ -9,6 +9,12 @@ export type BinarySearchResult = {
   path: string;
   loader: "node" | "native";
   yarnPnpLoaderPath?: string; // only set if loader is 'node' and found via Yarn PnP
+  /**
+   * When set, `BinaryWatcher` will watch this specific file instead of
+   * searching for a lock file. Used for global and settings-specified
+   * binaries that have no project lock file to watch.
+   */
+  watcherPath?: string;
 };
 
 /** @internal only used for testing */
@@ -188,6 +194,13 @@ export async function searchYarnPnpBin(
   return results.find(Boolean);
 }
 
+/** Attaches `watcherPath: result.path` to an existing result, used for global and settings binaries. */
+function withWatcherPath(
+  result: BinarySearchResult | undefined,
+): BinarySearchResult | undefined {
+  return result ? { ...result, watcherPath: result.path } : undefined;
+}
+
 /**
  * Search for the binary in global node_modules.
  * Returns undefined if not found.
@@ -202,11 +215,11 @@ export async function searchGlobalNodeModulesBin(
       require.resolve(binaryName, { paths: globalPaths }),
       binaryName,
     );
-    return { path: resolvedPath, loader: "node" };
+    return withWatcherPath({ path: resolvedPath, loader: "node" });
   } catch {}
 
   // fallback to direct binary lookup in global node_modules/.bin
-  return searchNodeModulesDefaultBinPath(binaryName, globalPaths);
+  return withWatcherPath(await searchNodeModulesDefaultBinPath(binaryName, globalPaths));
 }
 
 /**
@@ -249,7 +262,7 @@ export async function searchSettingsBin(
 
   try {
     await workspace.fs.stat(Uri.file(settingsBinary));
-    return { path: settingsBinary, loader: isNode ? "node" : "native" };
+    return withWatcherPath({ path: settingsBinary, loader: isNode ? "node" : "native" });
   } catch {}
 
   // on Windows, also check for `.exe` extension (bun uses `.exe` for its binaries)
@@ -260,7 +273,7 @@ export async function searchSettingsBin(
 
     try {
       await workspace.fs.stat(Uri.file(settingsBinary));
-      return { path: settingsBinary, loader: "native" };
+      return withWatcherPath({ path: settingsBinary, loader: "native" });
     } catch {}
   }
 

client/tools/BinaryWatcher.ts

@@ -0,0 +1,137 @@
+import { existsSync } from "node:fs";
+import * as path from "node:path";
+import { FileSystemWatcher, LogOutputChannel, RelativePattern, Uri, workspace } from "vscode";
+import { clearWorkspacePackageJsonNodeModulesCache } from "../findBinary";
+import type { BinarySearchResult } from "../findBinary";
+
+/**
+ * Glob pattern matching all known dependency lock files.
+ */
+const LOCK_FILE_GLOB = "{package-lock.json,yarn.lock,pnpm-lock.yaml,bun.lockb,bun.lock}";
+
+/**
+ * Lock file names in priority order, used when walking up the directory tree.
+ */
+const LOCK_FILE_NAMES = [
+  "package-lock.json",
+  "yarn.lock",
+  "pnpm-lock.yaml",
+  "bun.lockb",
+  "bun.lock",
+] as const;
+
+/**
+ * Watches for dependency changes so that tools are restarted automatically
+ * after `npm install`, `pnpm install`, `yarn install`, or `bun install` —
+ * without requiring a VS Code restart.
+ *
+ * **Project-local binaries** (no `watcherPath` set on `BinarySearchResult`):
+ * Walks up from the resolved binary path to find the project root containing a
+ * lock file and watches that directory. This correctly handles pnpm's versioned
+ * store layout (`.pnpm/pkg@version/node_modules/…`) where updating a package
+ * creates a brand-new directory instead of modifying the existing binary.
+ * Falls back to all workspace folders when no binary is found yet (initial
+ * install) or no lock file is found on the walk.
+ *
+ * **Global / settings-specified binaries** (`watcherPath` set on
+ * `BinarySearchResult`): Watches that specific file for creation, change, and
+ * deletion, since global installs have no project lock file.
+ */
+export class BinaryWatcher {
+  private readonly watchers: FileSystemWatcher[] = [];
+
+  constructor(
+    binary: BinarySearchResult | undefined,
+    binaryName: string,
+    outputChannel: LogOutputChannel,
+    onBinaryChanged: () => Promise<void>,
+  ) {
+    if (binary?.watcherPath) {
+      // Global or settings-specified binary: watch the resolved binary file directly.
+      const watcher = workspace.createFileSystemWatcher(
+        new RelativePattern(
+          Uri.file(path.dirname(binary.watcherPath)),
+          path.basename(binary.watcherPath),
+        ),
+        false,
+        false,
+        false,
+      );
+      const fileHandler = async () => {
+        outputChannel.info(`Binary "${binaryName}" changed, restarting tool...`);
+        clearWorkspacePackageJsonNodeModulesCache();
+        await onBinaryChanged();
+      };
+      watcher.onDidCreate(fileHandler);
+      watcher.onDidChange(fileHandler);
+      watcher.onDidDelete(fileHandler);
+      this.watchers.push(watcher);
+      return;
+    }
+
+    // Project-local binary (or no binary found yet): watch lock files.
+    const watchDirs = resolveLockFileWatchDirectories(binary);
+    for (const dir of watchDirs) {
+      const watcher = workspace.createFileSystemWatcher(
+        new RelativePattern(Uri.file(dir), LOCK_FILE_GLOB),
+        false,
+        false,
+        false,
+      );
+      const lockHandler = async () => {
+        outputChannel.info(`Dependency lock file changed, restarting "${binaryName}" tool...`);
+        clearWorkspacePackageJsonNodeModulesCache();
+        await onBinaryChanged();
+      };
+      watcher.onDidCreate(lockHandler);
+      watcher.onDidChange(lockHandler);
+      watcher.onDidDelete(lockHandler);
+      this.watchers.push(watcher);
+    }
+  }
+
+  dispose(): void {
+    for (const watcher of this.watchers) {
+      watcher.dispose();
+    }
+  }
+}
+
+/**
+ * Returns the directories to watch for lock file changes.
+ *
+ * If a binary was resolved, walks up from its path to find the project root
+ * (the first ancestor containing a lock file). Falls back to all workspace
+ * folders when the binary is not found or no lock file exists on the walk.
+ */
+function resolveLockFileWatchDirectories(binary: BinarySearchResult | undefined): string[] {
+  const workspaceFolderPaths = (workspace.workspaceFolders ?? []).map((f) => f.uri.fsPath);
+
+  if (!binary) {
+    return workspaceFolderPaths;
+  }
+
+  const projectRoot = findProjectRoot(binary.path);
+  return projectRoot ? [projectRoot] : workspaceFolderPaths;
+}
+
+/**
+ * Walk up from `binaryPath` and return the first ancestor directory that
+ * contains a known lock file. Returns `undefined` if none is found.
+ */
+function findProjectRoot(binaryPath: string): string | undefined {
+  let dir = path.dirname(binaryPath);
+  const root = path.parse(dir).root;
+
+  while (dir !== root) {
+    for (const lockFile of LOCK_FILE_NAMES) {
+      if (existsSync(path.join(dir, lockFile))) {
+        return dir;
+      }
+    }
+    dir = path.dirname(dir);
+  }
+
+  return undefined;
+}
+