fix(desktop): warn about Rosetta installs on Apple Silicon (#621)

* fix(desktop): warn about Rosetta installs on Apple Silicon

* docs: note workspace build sync before type fixes

packages/desktop/src/system/arm64-translation.test.ts

@@ -0,0 +1,59 @@
+import { describe, expect, it, vi } from "vitest";
+import { detectRunningUnderARM64Translation } from "./arm64-translation";
+
+describe("detectRunningUnderARM64Translation", () => {
+  it("returns false outside macOS without probing sysctl", () => {
+    const execFileSyncImpl = vi.fn();
+
+    expect(
+      detectRunningUnderARM64Translation({
+        platform: "linux",
+        electronReportedTranslation: true,
+        execFileSyncImpl,
+      }),
+    ).toBe(false);
+    expect(execFileSyncImpl).not.toHaveBeenCalled();
+  });
+
+  it("trusts Electron when it reports ARM64 translation", () => {
+    const execFileSyncImpl = vi.fn();
+
+    expect(
+      detectRunningUnderARM64Translation({
+        platform: "darwin",
+        electronReportedTranslation: true,
+        execFileSyncImpl,
+      }),
+    ).toBe(true);
+    expect(execFileSyncImpl).not.toHaveBeenCalled();
+  });
+
+  it("falls back to sysctl when Electron does not report translation", () => {
+    const execFileSyncImpl = vi.fn(() => "1\n");
+
+    expect(
+      detectRunningUnderARM64Translation({
+        platform: "darwin",
+        electronReportedTranslation: false,
+        execFileSyncImpl,
+      }),
+    ).toBe(true);
+    expect(execFileSyncImpl).toHaveBeenCalledWith("sysctl", ["-in", "sysctl.proc_translated"], {
+      encoding: "utf-8",
+      timeout: 1000,
+    });
+  });
+
+  it("treats missing sysctl support as not translated", () => {
+    const execFileSyncImpl = vi.fn(() => {
+      throw new Error("unknown oid");
+    });
+
+    expect(
+      detectRunningUnderARM64Translation({
+        platform: "darwin",
+        execFileSyncImpl,
+      }),
+    ).toBe(false);
+  });
+});

packages/desktop/src/system/arm64-translation.ts

@@ -0,0 +1,44 @@
+import { execFileSync } from "node:child_process";
+import { app } from "electron";
+
+const SYSCTL_TRANSLATED_KEY = "sysctl.proc_translated";
+
+let cachedRunningUnderARM64Translation: boolean | null = null;
+
+export function detectRunningUnderARM64Translation(input: {
+  platform: NodeJS.Platform;
+  electronReportedTranslation?: boolean;
+  execFileSyncImpl?: typeof execFileSync;
+}): boolean {
+  if (input.platform !== "darwin") {
+    return false;
+  }
+
+  if (input.electronReportedTranslation === true) {
+    return true;
+  }
+
+  const execImpl = input.execFileSyncImpl ?? execFileSync;
+
+  try {
+    const output = execImpl("sysctl", ["-in", SYSCTL_TRANSLATED_KEY], {
+      encoding: "utf-8",
+      timeout: 1000,
+    });
+    return output.trim() === "1";
+  } catch {
+    return false;
+  }
+}
+
+export function isRunningUnderARM64Translation(): boolean {
+  if (cachedRunningUnderARM64Translation !== null) {
+    return cachedRunningUnderARM64Translation;
+  }
+
+  cachedRunningUnderARM64Translation = detectRunningUnderARM64Translation({
+    platform: process.platform,
+    electronReportedTranslation: app.runningUnderARM64Translation,
+  });
+  return cachedRunningUnderARM64Translation;
+}