Add support for new Node.js builds for Apple silicon (#664)

* On Darwin, default to x64 for node versions below 16

* Prepare for release

* Add caveat about hole opened by searching for two architectures at once.

* Add Apple silicon details to README

CHANGELOG.md

@@ -7,7 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 <!-- markdownlint-disable MD024 -->
 
-## [Unreleased] (date goes here)
+## [7.2.0] (2021-04-18)
+
+### Added
+
+- install native arm64 Node.js on Macs with Apple silicon for Node.js 16 and higher (#664)
 
 ## [7.1.0] (2021-03-12)
 
@@ -355,10 +359,12 @@ Only minor functional changes, but technically could break scripts relying on sp
 [#644]: https://github.com/tj/n/pull/644
 [#649]: https://github.com/tj/n/issues/649
 [#654]: https://github.com/tj/n/issues/654
+[#654]: https://github.com/tj/n/pull/664
 
 <!-- reference links for releases -->
 
 [Unreleased]: https://github.com/tj/n/compare/master...develop
+[7.2.0]: https://github.com/tj/n/compare/v7.1.0...v7.2.0
 [7.1.0]: https://github.com/tj/n/compare/v7.0.2...v7.1.0
 [7.0.2]: https://github.com/tj/n/compare/v7.0.1...v7.0.2
 [7.0.1]: https://github.com/tj/n/compare/v7.0.0...v7.0.1

README.md

@@ -219,11 +219,18 @@ There is also `N_NODE_DOWNLOAD_MIRROR` for a different mirror with same layout a
 
 ## Custom Architecture
 
-By default `n` picks the binaries matching your system architecture, e.g. `n` will download 64 bit binaries for a 64 bit system. You can override this by using the `-a` or `--arch` option.
+By default `n` picks the binaries matching your system architecture. For example, on a 64 bit system `n` will download 64 bit binaries. 
 
-Download and use latest 32 bit version of Node.js:
+On a Mac with Apple silicon:
+- for Node.js 16 and higher, `n` defaults to arm64 binaries which run natively
+- for older versions of Node.js, `n` defaults to x64 binaries which run in Rosetta 2
 
-    n --arch x86 latest
+You can override the default architecture by using the `-a` or `--arch` option.
+
+e.g. reinstall latest version of Node.js with x64 binaries:
+
+    n rm current
+    n --arch x64 current
 
 ## Optional Environment Variables
 

bin/n

@@ -49,7 +49,7 @@ function n_grep() {
 # Setup and state
 #
 
-VERSION="7.1.1-0"
+VERSION="7.2.0"
 
 N_PREFIX="${N_PREFIX-/usr/local}"
 N_PREFIX=${N_PREFIX%/}
@@ -169,6 +169,16 @@ function set_insecure() {
   WGET_OPTIONS+=( "--no-check-certificate" )
 }
 
+#
+# Synposis: display_major_version numeric-version
+#
+display_major_version() {
+    local version=$1
+    version="${version#v}"
+    version="${version%%.*}"
+    echo "${version}"
+}
+
 #
 # Synopsis: update_mirror_settings_for_version version
 # e.g. <nightly/latest> means using download mirror and folder is nightly
@@ -190,7 +200,7 @@ function update_mirror_settings_for_version() {
 }
 
 #
-# Synopsis: update_xz_settings_for_version version
+# Synopsis: update_xz_settings_for_version numeric-version
 # Globals modified:
 # - N_USE_XZ
 #
@@ -198,14 +208,30 @@ function update_mirror_settings_for_version() {
 function update_xz_settings_for_version() {
   # tarballs in xz format were available in later version of iojs, but KISS and only use xz from v4.
   if [[ "${N_USE_XZ}" = "true" ]]; then
-    local resolved_major_version
-    resolved_major_version="$(echo "${1#v}" | cut -d '.' -f '1')"
-    if [[ "${resolved_major_version}" -lt 4 ]]; then
+    local major_version="$(display_major_version "$1")"
+    if [[ "${major_version}" -lt 4 ]]; then
       N_USE_XZ="false"
     fi
   fi
 }
 
+#
+# Synopsis: update_arch_settings_for_version numeric-version
+# Globals modified:
+# - ARCH
+#
+
+function update_arch_settings_for_version() {
+  local tarball_platform="$(display_tarball_platform)"
+  if [[ -z "${ARCH}" && "${tarball_platform}" = "darwin-arm64" ]]; then
+    # First native builds were for v16, but can use x64 in rosetta for older versions.
+    local major_version="$(display_major_version "$1")"
+    if [[ "${major_version}" -lt 16 ]]; then
+      ARCH=x64
+    fi
+  fi
+}
+
 #
 # Synopsis: is_lts_codename version
 #
@@ -709,6 +735,7 @@ install() {
   [[ -n "${version}" ]] || abort "no version found for '$1'"
   update_mirror_settings_for_version "$1"
   update_xz_settings_for_version "${version}"
+  update_arch_settings_for_version "${version}"
 
   local dir="${CACHE_DIR}/${g_mirror_folder_name}/${version}"
 
@@ -952,10 +979,8 @@ function display_tarball_platform() {
       arch="${uname_m}"
       ;;
   esac
-  # Override from command line.
+    # Override from command line, or version specific adjustment.
   [ -n "$ARCH" ] && arch="$ARCH"
-  # Fallback to x64 if autodetecting on Apple M1, native versions not available yet.
-  [[ -z "$ARCH" && "$os" == "darwin" && "$arch" == "arm64" ]] && arch=x64
 
   echo "${os}-${arch}"
 }
@@ -967,7 +992,11 @@ function display_tarball_platform() {
 
 function display_compatible_file_field {
   local compatible_file_field="$(display_tarball_platform)"
-  if [[ "${compatible_file_field}" =~ darwin-(.*) ]]; then
+  if [[ -z "${ARCH}" && "${compatible_file_field}" = "darwin-arm64" ]]; then
+    # Look for arm64 for native but also x64 for older versions which can run in rosetta.
+    # (Downside is will get an install error if install version above 16 with x64 and not arm64.)
+    compatible_file_field="osx-arm64-tar|osx-x64-tar"
+  elif [[ "${compatible_file_field}" =~ darwin-(.*) ]]; then
     compatible_file_field="osx-${BASH_REMATCH[1]}-tar"
   fi
   echo "${compatible_file_field}"