fix(server): device list warnings keep the hub's error detail

apps/server/src/device/DeviceHubOperations.ts

@@ -39,6 +39,21 @@ const HubActionResult = Schema.Struct({
   ),
 });
 
+// Hub diagnostics can carry a whole stderr dump.
+const boundDiagnostics = (text: string) =>
+  text.length > 2_000 ? `${text.slice(0, 1_999)}…` : text;
+
+// The hub's `error` is a util.inspect of Node's exec error; the stack and the
+// inspected fields follow the first frame, so keep the lines before it.
+const errorHead = (error: string) => {
+  const lines = error.split(/\r?\n/);
+  const firstFrame = lines.findIndex((line) => /^\s+at /.test(line));
+  return (firstFrame === -1 ? lines : lines.slice(0, firstFrame))
+    .map((line) => line.trim())
+    .filter(Boolean)
+    .join(" ");
+};
+
 const vendorPrefix = (platform: DevicePlatform) =>
   platform === "ios" ? "/vendor/serve-sim" : "/vendor/serve-emu";
 
@@ -109,7 +124,11 @@ export const makeDeviceHubOperations = (options: {
           /(?:^Error:\s*ENOENT:|\bcode:\s*['"]ENOENT['"])/.test(error.error ?? "")
         ),
     );
-    const details = warnings?.map((error) => error.message) ?? [];
+    const details =
+      warnings?.map((error) => {
+        const head = errorHead(error.error ?? "");
+        return boundDiagnostics(head ? `${error.message} ${head}` : error.message);
+      }) ?? [];
     let androidDiscoveryIncomplete = false;
     if (androidAvailable) {
       const avds = yield* run("emulator", ["-list-avds"]);
@@ -167,12 +186,7 @@ export const makeDeviceHubOperations = (options: {
           : /timed? out|timeout/i.test(diagnostics)
             ? "timeout"
             : "launch_failed",
-        ...(diagnostics
-          ? {
-              diagnostics:
-                diagnostics.length > 2_000 ? `${diagnostics.slice(0, 1_999)}…` : diagnostics,
-            }
-          : {}),
+        ...(diagnostics ? { diagnostics: boundDiagnostics(diagnostics) } : {}),
         cause: result,
       });
     }

apps/server/src/device/DeviceService.test.ts

@@ -522,6 +522,57 @@ it.effect("hides Android discovery failures when the host has no Android SDK", (
   }).pipe(Effect.scoped),
 );
 
+// The hub reports `error` as a util.inspect of Node's exec error.
+const simctlMessage = "[apple-utils] Failed to run `xcrun simctl list devices --json`:";
+const simctlCause =
+  "An error was encountered processing the command (domain=NSPOSIXErrorDomain, code=60): Unable to connect to CoreSimulatorService [xcrun shim fail mode]";
+const simctlError = `Error: Command failed: xcrun simctl list devices --json
+${simctlCause}
+
+    at genericNodeError (node:internal/errors:986:15)
+    at wrappedFn (node:internal/errors:540:14)
+    at ChildProcess.exithandler (node:child_process:417:12)
+    at ChildProcess._handle.onexit (node:internal/child_process:335:5) {
+  code: 1,
+  killed: false,
+  signal: null,
+  cmd: 'xcrun simctl list devices --json',
+  stdout: '',
+  stderr: '${simctlCause}\\n'
+}`;
+const avdmanager = "/Users/test/Library/Android/sdk/cmdline-tools/latest/bin/avdmanager";
+const avdmanagerError = `Error: spawn ${avdmanager} ENOENT
+    at ChildProcess._handle.onexit (node:internal/child_process:316:19)
+    at onErrorNT (node:internal/child_process:524:16) {
+  errno: -2,
+  code: 'ENOENT',
+  syscall: 'spawn ${avdmanager}',
+  path: '${avdmanager}',
+  spawnargs: [ 'list', 'avd' ],
+  cmd: '${avdmanager} list avd',
+  stdout: '',
+  stderr: ''
+}`;
+
+it.effect("keeps the cause from the hub's error in discovery warnings, without the stack", () =>
+  Effect.gen(function* () {
+    const { service, discoveryErrors } = yield* fixture();
+    yield* Ref.set(discoveryErrors, [
+      { message: simctlMessage, error: simctlError },
+      { message: "[android-utils] Failed to run `avdmanager list avd`:", error: avdmanagerError },
+    ]);
+    const state = yield* service.configure({ enabled: true });
+    expect(state.hostStatusDetail).toBe(
+      [
+        `${simctlMessage} Error: Command failed: xcrun simctl list devices --json ${simctlCause}`,
+        `[android-utils] Failed to run \`avdmanager list avd\`: Error: spawn ${avdmanager} ENOENT`,
+      ].join("\n"),
+    );
+    expect(state.hostStatusDetail).not.toContain("    at ");
+    expect(state.hostStatusDetail).not.toContain("stderr:");
+  }).pipe(Effect.scoped),
+);
+
 it.effect.each([
   {
     diagnostic: "Insufficient disk space at /private/user/path",