fix: mac bundle now proper arm64

lib/bds/mac_bundle.ex

@@ -12,7 +12,7 @@ defmodule BDS.MacBundle do
 
       BDS2.app/Contents/
         Info.plist  PkgInfo
-        MacOS/bds2                 # launcher script (execs the release)
+        MacOS/bds2                 # native arm64 launcher (execs the release)
         Resources/AppIcon.icns
         Resources/rel/             # the mix release (ERTS bundled)
         Frameworks/                # relocated wx + transitive dylibs
@@ -45,18 +45,6 @@ defmodule BDS.MacBundle do
     EEx.eval_file(template_path("Info.plist.eex"), assigns)
   end
 
-  @doc "Render the `Contents/MacOS` launcher shell script."
-  @spec launcher(keyword()) :: String.t()
-  def launcher(opts \\ []) do
-    assigns = [
-      identifier: Keyword.get(opts, :identifier, @identifier),
-      name: Keyword.get(opts, :name, @display_name),
-      release_name: Keyword.get(opts, :release_name, @release_name)
-    ]
-
-    EEx.eval_file(template_path("launcher.sh.eex"), assigns)
-  end
-
   @doc """
   Assemble the `.app` from a built release directory.
 
@@ -96,9 +84,19 @@ defmodule BDS.MacBundle do
     end
   end
 
+  # The main executable must be a real arm64 Mach-O, not a shell script — a
+  # script has no Mach-O slices, so LaunchServices advertises x86_64 and offers
+  # Rosetta. Compile the native stub (launcher.c) in its place.
   defp write_launcher(path) do
-    with :ok <- File.write(path, launcher()) do
-      File.chmod(path, 0o755)
+    src = template_path("launcher.c")
+
+    case System.cmd(
+           "cc",
+           ["-arch", "arm64", "-O2", ~s(-DBDS_RELEASE_NAME="#{@release_name}"), "-o", path, src],
+           stderr_to_stdout: true
+         ) do
+      {_, 0} -> File.chmod(path, 0o755)
+      {out, code} -> {:error, "launcher compile failed (#{code}): #{out}"}
     end
   end
 
@@ -135,7 +133,8 @@ defmodule BDS.MacBundle do
   may reference a Homebrew/local (`/opt/homebrew`, `/usr/local`) path. This is a
   hard requirement — the app must run on a Mac without Homebrew installed.
   """
-  @spec verify_standalone(String.t()) :: :ok | {:error, {:external_refs, [{String.t(), String.t()}]}}
+  @spec verify_standalone(String.t()) ::
+          :ok | {:error, {:external_refs, [{String.t(), String.t()}]}}
   def verify_standalone(app) do
     offenders =
       app

priv/desktop/macos/Info.plist.eex

@@ -26,6 +26,11 @@
     <string><%= min_system %></string>
     <key>NSHighResolutionCapable</key>
     <true/>
+    <!-- Main executable is a shell script (no Mach-O slices), so LaunchServices
+         otherwise advertises x86_64 and offers Rosetta. All embedded binaries are
+         arm64; force native execution so the OS never translates the app. -->
+    <key>LSRequiresNativeExecution</key>
+    <true/>
     <key>LSApplicationCategoryType</key>
     <string>public.app-category.developer-tools</string>
     <key>CFBundleURLTypes</key>

priv/desktop/macos/launcher.c

@@ -0,0 +1,51 @@
+// Native launcher for the BDS2 .app — compiled to a pure arm64 Mach-O by
+// mix bds.bundle.macos. A shell-script main executable has no Mach-O slices, so
+// LaunchServices advertises x86_64 and offers Rosetta; a real arm64 binary makes
+// the bundle unambiguously Apple Silicon.
+//
+// Mirrors launcher.sh: resolve <Contents>, prepend Frameworks to the dyld
+// fallback path, then exec <Contents>/Resources/rel/bin/<release> start.
+#include <limits.h>
+#include <libgen.h>
+#include <mach-o/dyld.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifndef BDS_RELEASE_NAME
+#define BDS_RELEASE_NAME "bds"
+#endif
+
+int main(void) {
+  char exec_path[PATH_MAX];
+  uint32_t size = sizeof(exec_path);
+  if (_NSGetExecutablePath(exec_path, &size) != 0) return 1;
+
+  char resolved[PATH_MAX];
+  if (realpath(exec_path, resolved) == NULL) return 1;
+
+  // resolved = <Contents>/MacOS/bds2 ; climb two dirs to <Contents>.
+  char macos[PATH_MAX];
+  strncpy(macos, dirname(resolved), sizeof(macos) - 1);
+  macos[sizeof(macos) - 1] = '\0';
+  char *contents = dirname(macos);
+
+  char frameworks[PATH_MAX];
+  snprintf(frameworks, sizeof(frameworks), "%s/Frameworks", contents);
+
+  const char *existing = getenv("DYLD_FALLBACK_LIBRARY_PATH");
+  char fallback[2 * PATH_MAX];
+  if (existing && *existing)
+    snprintf(fallback, sizeof(fallback), "%s:%s", frameworks, existing);
+  else
+    snprintf(fallback, sizeof(fallback), "%s", frameworks);
+  setenv("DYLD_FALLBACK_LIBRARY_PATH", fallback, 1);
+
+  char bin[PATH_MAX];
+  snprintf(bin, sizeof(bin), "%s/Resources/rel/bin/%s", contents, BDS_RELEASE_NAME);
+
+  execl(bin, BDS_RELEASE_NAME, "start", (char *)NULL);
+  perror("execl");  // only reached if exec failed
+  return 127;
+}

priv/desktop/macos/launcher.sh.eex

@@ -1,17 +0,0 @@
-#!/bin/sh
-# Launcher for <%= name %> (<%= identifier %>).
-# Generated by mix bds.bundle.macos — do not edit inside the .app.
-#
-# Resolves the bundle's own location and execs the embedded Elixir release.
-# wxWidgets dylibs live in ../Frameworks and are referenced via @loader_path, so
-# the app is self-contained regardless of where the BEAM executable runs from.
-set -e
-
-HERE="$(cd "$(dirname "$0")" && pwd)"
-APP_CONTENTS="$(cd "$HERE/.." && pwd)"
-RELEASE_ROOT="$APP_CONTENTS/Resources/rel"
-
-# Belt-and-suspenders fallback for dyld (primary resolution is @loader_path).
-export DYLD_FALLBACK_LIBRARY_PATH="$APP_CONTENTS/Frameworks:${DYLD_FALLBACK_LIBRARY_PATH:-}"
-
-exec "$RELEASE_ROOT/bin/<%= release_name %>" start

test/bds/mac_bundle_test.exs

@@ -168,7 +168,10 @@ defmodule BDS.MacBundleTest do
     end
 
     test "honors a NIF-relative loader prefix" do
-      assert Dylibs.relink_changes(["/opt/homebrew/lib/libfoo.dylib"], "@loader_path/../../Frameworks") ==
+      assert Dylibs.relink_changes(
+               ["/opt/homebrew/lib/libfoo.dylib"],
+               "@loader_path/../../Frameworks"
+             ) ==
                [{"/opt/homebrew/lib/libfoo.dylib", "@loader_path/../../Frameworks/libfoo.dylib"}]
     end
   end
@@ -299,6 +302,10 @@ defmodule BDS.MacBundleTest do
   end
 
   describe "MacBundle.assemble/1" do
+    # assemble/1 compiles the native arm64 launcher with `cc -arch arm64`, so it
+    # needs the macOS toolchain (the only platform that builds the .app anyway).
+    @describetag :macos_tools
+
     setup do
       tmp = Path.join(System.tmp_dir!(), "bds-macbundle-#{System.unique_integer([:positive])}")
       release = Path.join(tmp, "rel")
@@ -344,14 +351,15 @@ defmodule BDS.MacBundleTest do
       assert File.read!(Path.join(app, "Contents/PkgInfo")) == "APPL????"
     end
 
-    test "installs an executable launcher that execs the release", %{app: app} do
+    test "installs an executable, arm64-only Mach-O launcher", %{app: app} do
       launcher = Path.join(app, "Contents/MacOS/bds2")
       assert File.exists?(launcher)
       %File.Stat{mode: mode} = File.stat!(launcher)
       assert (mode &&& 0o111) != 0, "launcher must be executable"
-      script = File.read!(launcher)
-      assert script =~ "Resources/rel"
-      assert script =~ "bin/bds"
+      # Must be a native arm64 Mach-O, not a script — a script has no Mach-O
+      # slices so LaunchServices advertises x86_64 and offers Rosetta.
+      {archs, 0} = System.cmd("lipo", ["-archs", launcher])
+      assert String.trim(archs) == "arm64"
     end
 
     test "copies the release tree and the icon into Resources", %{app: app} do