fix(vscode): reuse IPC server port across restarts (#252) (#256)

Persist the IPC port in workspaceState and try to rebind to it on
activation so restored terminals still have a valid PLANNOTATOR_VSCODE_PORT.
Falls back to a random port if the preferred one is taken.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

apps/vscode-extension/src/extension.ts

@@ -48,13 +48,16 @@ export async function activate(context: vscode.ExtensionContext): Promise<void>
     vscode.window.showInformationMessage("Plannotator panel opened");
   };
 
-  // Start local IPC server to receive URLs from the router script
+  // Start local IPC server to receive URLs from the router script.
+  // Reuse the last port so restored terminals still have a valid PLANNOTATOR_VSCODE_PORT.
+  const lastPort = context.workspaceState.get<number>("ipcPort");
   const { server, port } = await createIpcServer((url) => {
     openInPanel(url).catch((err) => {
       log.error(`[open] failed: ${err}`);
       vscode.window.showErrorMessage(`Plannotator: ${err}`);
     });
-  });
+  }, lastPort);
+  context.workspaceState.update("ipcPort", port);
   context.subscriptions.push({ dispose: () => server.close() });
 
   // Inject env vars into integrated terminals

apps/vscode-extension/src/ipc-server.ts

@@ -6,31 +6,39 @@ import * as http from "http";
  */
 export function createIpcServer(
   onUrl: (url: string) => void,
+  preferredPort?: number,
 ): Promise<{ server: http.Server; port: number }> {
-  return new Promise((resolve, reject) => {
-    const server = http.createServer((req, res) => {
-      const parsed = new globalThis.URL(req.url!, "http://localhost");
-      const targetUrl = parsed.searchParams.get("url");
+  const handler = (req: http.IncomingMessage, res: http.ServerResponse) => {
+    const parsed = new globalThis.URL(req.url!, "http://localhost");
+    const targetUrl = parsed.searchParams.get("url");
 
-      if (req.method === "GET" && parsed.pathname === "/open" && targetUrl) {
-        onUrl(targetUrl);
-        res.writeHead(200);
-        res.end("ok");
-      } else {
-        res.writeHead(404);
-        res.end("not found");
-      }
+    if (req.method === "GET" && parsed.pathname === "/open" && targetUrl) {
+      onUrl(targetUrl);
+      res.writeHead(200);
+      res.end("ok");
+    } else {
+      res.writeHead(404);
+      res.end("not found");
+    }
+  };
+
+  function listen(port: number): Promise<{ server: http.Server; port: number }> {
+    return new Promise((resolve, reject) => {
+      const server = http.createServer(handler);
+      server.listen(port, "127.0.0.1", () => {
+        const addr = server.address();
+        if (addr && typeof addr === "object") {
+          resolve({ server, port: addr.port });
+        } else {
+          reject(new Error("Failed to get server address"));
+        }
+      });
+      server.on("error", reject);
     });
+  }
 
-    server.listen(0, "127.0.0.1", () => {
-      const addr = server.address();
-      if (addr && typeof addr === "object") {
-        resolve({ server, port: addr.port });
-      } else {
-        reject(new Error("Failed to get server address"));
-      }
-    });
-
-    server.on("error", reject);
-  });
+  if (preferredPort) {
+    return listen(preferredPort).catch(() => listen(0));
+  }
+  return listen(0);
 }