Index: track off-editor file changes via didChangeWatchedFiles

The cross-index previously only learned about changes through open
documents -- files created, changed, or deleted outside the editor (git
pull, code generators) went stale until a server restart. Now:

- client.js registers file watchers for **/*.{lpc,c,h} and the driver
  config spots (config, config.*, *.cfg, *.conf), forwarding events to
  the server.
- The server's onDidChangeWatchedFiles re-indexes changed/created files
  from disk (open documents stay authoritative via their live buffers),
  removes deleted ones, and clears the driver-config discovery cache
  when a config-looking path changes -- a config appearing mid-session
  is picked up without a restart.
- indexer.updateFromDisk() drops the mtime short-circuit so a watched
  change always re-reads.

Harness: create a file on disk (never opened) -> notify -> it serves
workspace/symbol; delete -> notify -> it's gone. Both green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AXqX4Kf55ArA39suS9cdCv

Author: claude

extension/client.js

@@ -29,7 +29,15 @@ async function start(ctx) {
     },
     {
       documentSelector: [{ language: 'lpc' }],
-      synchronize: { configurationSection: 'lpc' },
+      synchronize: {
+        configurationSection: 'lpc',
+        // Off-editor changes (git pull, generators): keeps the workspace
+        // cross-index fresh and re-triggers driver-config discovery.
+        fileEvents: [
+          vscode.workspace.createFileSystemWatcher('**/*.{lpc,c,h}'),
+          vscode.workspace.createFileSystemWatcher('**/{config,config.*,*.cfg,*.conf}'),
+        ],
+      },
       initializationOptions: {
         settings: vscode.workspace.getConfiguration('lpc'),
       },

extension/server/indexer.js

@@ -83,6 +83,14 @@ function createIndex({ tokenize, outline }) {
       if (roots.length > 0 && !roots.some((r) => abs.startsWith(r + path.sep))) return;
       indexText(abs, text, Date.now());
     },
+    // Re-index one file from disk (didChangeWatchedFiles: files changed
+    // OUTSIDE the editor -- git pull, generators).
+    updateFromDisk(abs) {
+      if (roots.length > 0 && !roots.some((r) => abs.startsWith(r + path.sep))) return;
+      if (!/\.(lpc|c|h)$/.test(abs)) return;
+      files.delete(abs); // drop the mtime short-circuit: always re-read
+      indexFile(abs);
+    },
     remove(abs) { files.delete(abs); },
 
     // name -> [{file, kind, name, line, col}] (tokenizer 1-based positions

extension/server/main.js

@@ -620,6 +620,25 @@ connection.onInitialize((params) => {
 
 connection.onInitialized(() => startIndex());
 
+// Files changed OUTSIDE the editor (git pull, generators, deletes). The VS
+// Code client watches **/*.{lpc,c,h} plus driver-config spots; other
+// clients can send the same notification.
+connection.onDidChangeWatchedFiles((params) => {
+  for (const change of params.changes || []) {
+    let abs;
+    try { abs = fileURLToPath(change.uri); } catch (_e) { continue; }
+    // A driver config appearing/changing invalidates discovery.
+    if (/(^|[\\/])(config[^\\/]*|[^\\/]+\.(cfg|conf))$/i.test(abs)) configDiscovery.clear();
+    if (!index) continue;
+    if (change.type === 3 /* Deleted */) {
+      index.remove(abs);
+    } else if (!documents.get(pathToFileURL(abs).href)) {
+      // open documents are already authoritative via reindexDoc
+      index.updateFromDisk(abs);
+    }
+  }
+});
+
 connection.onDidChangeConfiguration((change) => {
   settings = (change.settings && change.settings.lpc) || {};
   configDiscovery.clear();

scripts/test-lsp.mjs

@@ -295,6 +295,26 @@ const wsym = await request('workspace/symbol', { query: 'util_f' });
 check('workspace/symbol: substring search over the index',
       wsym && wsym.some((s) => s.name === 'util_fn' && s.location.uri === utilUri));
 
+// watched-files: a file created OUTSIDE the editor enters the index...
+const latePath = path.join(mudlib, 'lib', 'late.lpc');
+fs.writeFileSync(latePath, 'int late_fn() { return 9; }\n');
+notify('workspace/didChangeWatchedFiles', {
+  changes: [{ uri: pathToFileURL(latePath).href, type: 1 }],
+});
+await new Promise((r) => setTimeout(r, 200));
+const lateSym = await request('workspace/symbol', { query: 'late_fn' });
+check('watched files: off-editor create is indexed',
+      lateSym && lateSym.some((s) => s.name === 'late_fn'));
+// ... and an off-editor delete leaves the index
+fs.unlinkSync(latePath);
+notify('workspace/didChangeWatchedFiles', {
+  changes: [{ uri: pathToFileURL(latePath).href, type: 3 }],
+});
+await new Promise((r) => setTimeout(r, 200));
+const goneSym = await request('workspace/symbol', { query: 'late_fn' });
+check('watched files: off-editor delete leaves the index',
+      goneSym && !goneSym.some((s) => s.name === 'late_fn'));
+
 const comp = await request('textDocument/completion', {
   textDocument: { uri: sampleUri }, position: { line: greetUse, character: 2 },
 });