Allow using newer solc on macOS without Rosetta

`solc` universal binaries are now available, starting from 0.8.24.
Allow Macs without Rosetta to run those binaries.

README.md

@@ -22,7 +22,7 @@ To automatically install and use a version, run `solc-select use <version> --alw
 
 ### Running on ARM (Mac M1/M2)
 
-`solc` requires Rosetta to be installed. See the FAQ on [how to install Rosetta](#oserror-errno-86-bad-cpu-type-in-executable).
+`solc` older than 0.8.24 requires Rosetta to be installed. See the FAQ on [how to install Rosetta](#oserror-errno-86-bad-cpu-type-in-executable).
 
 ## Usage
 
@@ -85,10 +85,12 @@ Feel free to stop by our [Slack channel](https://empirehacking.slack.com/) for h
 ### OSError: [Errno 86] Bad CPU type in executable
 
 On newer `solc-select` versions, this might show as `solc binaries for macOS are
-Intel-only. Please install Rosetta on your Mac to continue.`
+Intel-only. Please install Rosetta on your Mac to continue.` or `solc binaries
+previous to 0.8.24 for macOS are Intel-only. Please install Rosetta on your Mac
+to continue.`
 
-`solc` requires Rosetta to be installed. To see whether you have Rosetta
-installed on your Mac, run
+`solc` releases earlier than 0.8.24 require Rosetta to be installed. To see
+whether you have Rosetta installed on your Mac, run
 
 ```bash
 pgrep -q oahd && echo Rosetta is installed || echo Rosetta is NOT installed

solc_select/__main__.py

@@ -94,7 +94,7 @@ def solc() -> None:
         (version, _) = res
         path = ARTIFACTS_DIR.joinpath(f"solc-{version}", f"solc-{version}")
         halt_old_architecture(path)
-        halt_incompatible_system()
+        halt_incompatible_system(path)
         try:
             subprocess.run(
                 [str(path)] + sys.argv[1:],

solc_select/solc_select.py

@@ -20,7 +20,7 @@
     CRYTIC_SOLC_ARTIFACTS,
     CRYTIC_SOLC_JSON,
 )
-from .utils import mac_can_run_intel_binaries
+from .utils import mac_binary_is_universal, mac_can_run_intel_binaries
 
 Path.mkdir(ARTIFACTS_DIR, parents=True, exist_ok=True)
 
@@ -32,10 +32,19 @@ def halt_old_architecture(path: Path) -> None:
         )
 
 
-def halt_incompatible_system() -> None:
-    if soliditylang_platform() == MACOSX_AMD64 and not mac_can_run_intel_binaries():
+def halt_incompatible_system(path: Path) -> None:
+    if soliditylang_platform() == MACOSX_AMD64:
+        # If Rosetta is available, we can run all solc versions
+        if mac_can_run_intel_binaries():
+            return
+
+        # If this is a newer universal solc (>=0.8.24) we can always run it
+        # https://github.com/ethereum/solidity/issues/12291#issuecomment-2223328961
+        if mac_binary_is_universal(path):
+            return
+
         raise argparse.ArgumentTypeError(
-            "solc binaries for macOS are Intel-only. Please install Rosetta on your Mac to continue. Refer to the solc-select README for instructions."
+            "solc binaries previous to 0.8.24 for macOS are Intel-only. Please install Rosetta on your Mac to continue. Refer to the solc-select README for instructions."
         )
     # TODO: check for Linux aarch64 (e.g. RPi), presence of QEMU+binfmt
 

solc_select/utils.py

@@ -1,3 +1,4 @@
+from pathlib import Path
 import platform
 import subprocess
 import sys
@@ -6,6 +7,16 @@
 from packaging.version import Version
 
 
+def mac_binary_is_universal(path: Path):
+    """Check if the Mac binary is Universal or not. Will throw an exception if run on non-macOS."""
+    assert sys.platform == "darwin"
+    result = subprocess.run(["/usr/bin/file", str(path)], capture_output=True, check=False)
+    is_universal = all(
+        text in result.stdout.decode() for text in ("Mach-O universal binary", "x86_64", "arm64")
+    )
+    return result.returncode == 0 and is_universal
+
+
 def mac_can_run_intel_binaries() -> bool:
     """Check if the Mac is Intel or M1 with available Rosetta. Will throw an exception if run on non-macOS."""
     assert sys.platform == "darwin"