From 5a7b286f41ccf2fef84b561db9cb369e125c194e Mon Sep 17 00:00:00 2001
From: Benjamin Faershtein <119711889+RCGV1@users.noreply.github.com>
Date: Tue, 21 Jul 2026 23:30:42 -0700
Subject: [PATCH] Prompt for duplicate serial devices

---
 .../src/core/connections/transports.test.ts   | 51 +++++++++++++++++++
 apps/web/src/core/connections/transports.ts   | 13 ++++-
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 apps/web/src/core/connections/transports.test.ts

diff --git a/apps/web/src/core/connections/transports.test.ts b/apps/web/src/core/connections/transports.test.ts
new file mode 100644
index 000000000..f78efb229
--- /dev/null
+++ b/apps/web/src/core/connections/transports.test.ts
@@ -0,0 +1,51 @@
+import { TransportWebSerial } from "@meshtastic/transport-web-serial";
+import { Result } from "better-result";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { openTransport } from "./transports.ts";
+
+vi.mock("@meshtastic/transport-web-serial", () => ({
+  SerialConnectError: class SerialConnectError extends Error {},
+  TransportWebSerial: { createFromPort: vi.fn() },
+}));
+
+describe("openTransport serial selection", () => {
+  const info = { usbVendorId: 0x303a, usbProductId: 0x1001 };
+  const portA = { getInfo: () => info } as SerialPort;
+  const portB = { getInfo: () => info } as SerialPort;
+  const selectedPort = { getInfo: () => info } as SerialPort;
+  const requestPort = vi.fn();
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    requestPort.mockResolvedValue(selectedPort);
+    Object.defineProperty(navigator, "serial", {
+      configurable: true,
+      value: {
+        getPorts: vi.fn().mockResolvedValue([portA, portB]),
+        requestPort,
+      },
+    });
+    vi.mocked(TransportWebSerial.createFromPort).mockResolvedValue(
+      Result.ok({} as never),
+    );
+  });
+
+  it("prompts when multiple permitted ports share the saved VID/PID", async () => {
+    await openTransport(
+      {
+        id: 1,
+        name: "Serial: 303a:1001",
+        type: "serial",
+        status: "disconnected",
+        usbVendorId: info.usbVendorId,
+        usbProductId: info.usbProductId,
+      },
+      { allowPrompt: true },
+    );
+
+    expect(requestPort).toHaveBeenCalledOnce();
+    expect(TransportWebSerial.createFromPort).toHaveBeenCalledWith(
+      selectedPort,
+    );
+  });
+});
diff --git a/apps/web/src/core/connections/transports.ts b/apps/web/src/core/connections/transports.ts
index 9dfc81594..47f8147e1 100644
--- a/apps/web/src/core/connections/transports.ts
+++ b/apps/web/src/core/connections/transports.ts
@@ -160,7 +160,7 @@ async function openSerial(
     const ports = await serial.getPorts();
     log.debug("openSerial: getPorts", { count: ports.length });
     if (ports && conn.usbVendorId && conn.usbProductId) {
-      port = ports.find((p: SerialPort) => {
+      const matchingPorts = ports.filter((p: SerialPort) => {
         const info =
           (
             p as SerialPort & {
@@ -172,6 +172,17 @@ async function openSerial(
           info.usbProductId === conn.usbProductId
         );
       });
+      if (matchingPorts.length === 1) {
+        port = matchingPorts[0];
+      } else if (matchingPorts.length > 1) {
+        log.info(
+          "openSerial: multiple permitted ports share VID/PID; user selection required",
+          { count: matchingPorts.length },
+        );
+        if (opts.allowPrompt) {
+          port = await serial.requestPort({});
+        }
+      }
     }
   }
   if (!port && opts.allowPrompt) {