From 34573817b87fdae0b533ba070332882e9b6bd863 Mon Sep 17 00:00:00 2001
From: Bartosz Blizniak <bblizniak@cloudsmith.io>
Date: Mon, 20 Jul 2026 17:03:52 +0100
Subject: [PATCH] fix: select arm64 binary under Rosetta

---
 CHANGELOG.md             |  4 ++--
 README.md                |  2 +-
 install.sh               | 10 +++++++++-
 tests/detect_target.bats | 41 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3514e45..94e9b11 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,8 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Cross-platform `install.sh` and `install.ps1` installers for the standalone
   Cloudsmith CLI.
-- Automatic platform detection and support for selecting a specific CLI
-  version or target.
+- Automatic platform detection, including native Arm64 selection under
+  Rosetta 2, and support for selecting a specific CLI version or target.
 - SHA-256 verification, archive safety checks, atomic installation, and
   concurrent-install locking.
 - Stable machine-readable output for CI/CD consumers.
diff --git a/README.md b/README.md
index 7b00ce7..faa5643 100644
--- a/README.md
+++ b/README.md
@@ -131,7 +131,7 @@ executable=/home/runner/.local/share/cloudsmith-cli/1.19.0/linux-x86_64-gnu/clou
 | Linux | x86-64 | `linux-x86_64-musl` | Alpine and other musl distributions |
 | Linux | Arm64 | `linux-aarch64-musl` | Alpine and other musl distributions |
 | macOS | x86-64 | `macos-x86_64` | Intel |
-| macOS | Arm64 | `macos-arm64` | Apple silicon |
+| macOS | Arm64 | `macos-arm64` | Apple silicon, including shells running under Rosetta 2 |
 | Windows | x86-64 | `windows-x86_64` | Also used on Windows Arm64 through x86-64 emulation |
 
 ## Security
diff --git a/install.sh b/install.sh
index f0d6a4f..ca52526 100755
--- a/install.sh
+++ b/install.sh
@@ -157,7 +157,15 @@ detect_target() {
     Darwin)
       case "$machine" in
         arm64|aarch64) printf '%s\n' macos-arm64 ;;
-        x86_64|amd64) printf '%s\n' macos-x86_64 ;;
+        x86_64|amd64)
+          # A translated shell reports x86_64 even when the host is Apple
+          # silicon. Prefer the native CLI binary when Rosetta 2 is detected.
+          if [ "$(sysctl -n sysctl.proc_translated 2>/dev/null || true)" = 1 ]; then
+            printf '%s\n' macos-arm64
+          else
+            printf '%s\n' macos-x86_64
+          fi
+          ;;
         *) die "unsupported macOS architecture: $machine" ;;
       esac
       ;;
diff --git a/tests/detect_target.bats b/tests/detect_target.bats
index 865d0e1..84eba4c 100644
--- a/tests/detect_target.bats
+++ b/tests/detect_target.bats
@@ -37,6 +37,22 @@ EOF
   chmod +x "$STUB_BIN/uname"
 }
 
+# write_sysctl_stub <native|translated|unavailable>: fakes Apple's Rosetta probe.
+write_sysctl_stub() {
+  local mode="$1"
+  cat > "$STUB_BIN/sysctl" <<EOF
+#!/usr/bin/env bash
+[ "\${1-}" = "-n" ] || exit 2
+[ "\${2-}" = "sysctl.proc_translated" ] || exit 2
+case "$mode" in
+  native) printf '%s\n' 0 ;;
+  translated) printf '%s\n' 1 ;;
+  unavailable) exit 1 ;;
+esac
+EOF
+  chmod +x "$STUB_BIN/sysctl"
+}
+
 # write_getconf_stub <gnu|fail>: "gnu" simulates glibc; "fail" forces the ldd fallback.
 write_getconf_stub() {
   local mode="$1"
@@ -72,6 +88,31 @@ write_ldd_stub() {
 
 @test "darwin/x86_64 is detected as macos-x86_64" {
   write_uname_stub Darwin x86_64
+  write_sysctl_stub native
+
+  run --separate-stderr "$INSTALL_SH" \
+    --install-root "$INSTALL_ROOT" \
+    --manifest-url "$UNREACHABLE_MANIFEST_URL"
+
+  [ "$status" -ne 0 ]
+  [[ "$stderr" == *"detected target macos-x86_64"* ]]
+}
+
+@test "darwin/x86_64 under Rosetta is detected as macos-arm64" {
+  write_uname_stub Darwin x86_64
+  write_sysctl_stub translated
+
+  run --separate-stderr "$INSTALL_SH" \
+    --install-root "$INSTALL_ROOT" \
+    --manifest-url "$UNREACHABLE_MANIFEST_URL"
+
+  [ "$status" -ne 0 ]
+  [[ "$stderr" == *"detected target macos-arm64"* ]]
+}
+
+@test "darwin/x86_64 stays macos-x86_64 when the Rosetta probe is unavailable" {
+  write_uname_stub Darwin x86_64
+  write_sysctl_stub unavailable
 
   run --separate-stderr "$INSTALL_SH" \
     --install-root "$INSTALL_ROOT" \