pw_env_setup: Support M1 Macs via Rosetta

If we're running on an M1 (arm64) Mac, pretend to be on an
amd64 Mac instead. The environment will run transparently
via Rosetta.

Bug: b/224408077
Change-Id: I003ee41302e88760ec9528875e0c764b4484bd33
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/88340
Commit-Queue: Chad Norvell <chadnorvell@google.com>
Reviewed-by: Rob Mohr <mohrr@google.com>

3 files changed, 26 insertions, 5 deletions

diff --git a/pw_env_setup/get_pw_env_setup.sh b/pw_env_setup/get_pw_env_setup.sh
index 0317b2e7a..ff74220bd 100755
--- a/pw_env_setup/get_pw_env_setup.sh
+++ b/pw_env_setup/get_pw_env_setup.sh
@@ -46,6 +46,11 @@ if [ "$ARCH" = "x86_64" ]; then
   ARCH="amd64"
 fi
 
+# Support `mac-arm64` through Rosetta until `mac-arm64` binaries are ready
+if [[ "$OS" = "mac" ] && [ "$ARCH" = "arm64" ]]; then
+  ARCH="amd64"
+fi
+
 for HASH in $(git --git-dir="$PW_ROOT/.git" --no-pager log --max-count=10 --format=format:%H); do
   URL="https://storage.googleapis.com/pigweed-envsetup/$OS-$ARCH"
   URL="$URL/$HASH/pw_env_setup"
diff --git a/pw_env_setup/py/pw_env_setup/cipd_setup/update.py b/pw_env_setup/py/pw_env_setup/cipd_setup/update.py
index 27acfbee9..eb2b835b1 100755
--- a/pw_env_setup/py/pw_env_setup/cipd_setup/update.py
+++ b/pw_env_setup/py/pw_env_setup/cipd_setup/update.py
@@ -134,7 +134,13 @@ def platform():
     else:
         arch = platform_module.machine()
 
-    return '{}-{}'.format(osname, arch).lower()
+    platform_arch = '{}-{}'.format(osname, arch).lower()
+
+    # Support `mac-arm64` through Rosetta until `mac-arm64` binaries are ready
+    if platform_arch == 'mac-arm64':
+        return 'mac-amd64'
+
+    return platform_arch
 
 
 def all_package_files(env_vars, package_files):
diff --git a/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py b/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py
index 466f2911e..6ca7db3c9 100755
--- a/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py
+++ b/pw_env_setup/py/pw_env_setup/cipd_setup/wrapper.py
@@ -133,6 +133,16 @@ def arch_normalized():
     raise Exception('unrecognized arch: {}'.format(machine))
 
 
+def platform_arch_normalized():
+    platform_arch = '{}-{}'.format(platform_normalized(), arch_normalized())
+
+    # Support `mac-arm64` through Rosetta until `mac-arm64` binaries are ready
+    if platform_arch == 'mac-arm64':
+        platform_arch = 'mac-amd64'
+
+    return platform_arch
+
+
 def user_agent():
     """Generate a user-agent based on the project name and current hash."""
 
@@ -160,7 +170,7 @@ def actual_hash(path):
 def expected_hash():
     """Pulls expected hash from digests file."""
 
-    expected_plat = '{}-{}'.format(platform_normalized(), arch_normalized())
+    expected_plat = platform_arch_normalized()
 
     with open(DIGESTS_FILE, 'r') as ins:
         for line in ins:
@@ -223,7 +233,7 @@ brew uninstall python && brew install python
         print('=' * 70)
         raise
 
-    full_platform = '{}-{}'.format(platform_normalized(), arch_normalized())
+    full_platform = platform_arch_normalized()
     if full_platform not in SUPPORTED_PLATFORMS:
         raise UnsupportedPlatform(full_platform)
 
@@ -293,8 +303,8 @@ def bootstrap(client, silent=('PW_ENVSETUP_QUIET' in os.environ)):
         os.makedirs(client_dir)
 
     if not silent:
-        print('Bootstrapping cipd client for {}-{}'.format(
-            platform_normalized(), arch_normalized()))
+        print('Bootstrapping cipd client for {}'.format(
+            platform_arch_normalized()))
 
     tmp_path = client + '.tmp'
     with open(tmp_path, 'wb') as tmp: