ci: build only native architecture on each macOS runner

Previously cibuildwheel was configured to build both x86_64 and arm64
wheels on BOTH runners, causing unnecessary cross-compilation:
- macos-14 (ARM) was cross-compiling x86_64 via Rosetta
- macos-15-intel (x86) was cross-compiling arm64

This was slower, less reliable, and produced duplicate wheels.

Changes:
- Set CIBW_ARCHS_MACOS per-runner: arm64 on macos-14, x86_64 on macos-15-intel
- Removed macos.archs from cibuildwheel.toml (now set in workflow)
- Removed test-skip config (no longer needed without cross-arch builds)
- Each runner now builds only its native architecture

Benefits:
- Faster builds (no cross-compilation overhead)
- More reliable (no Rosetta issues)
- Cleaner artifact naming (no duplicates)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: corneliusroemer

.github/workflows/build_and_publish.yml

@@ -71,12 +71,12 @@ jobs:
           CIBW_BUILD: "cp${{ matrix.python-version}}-*"
           # Override deployment target to 14.0 for all macOS runners
           MACOSX_DEPLOYMENT_TARGET: "14.0"
-          # Skip cross-architecture testing to avoid brew/Rosetta issues
-          CIBW_TEST_SKIP: >-
+          # Build only native architecture on each runner (no cross-compilation)
+          CIBW_ARCHS_MACOS: >-
             ${{
-              matrix.os == 'macos-14' && '*macosx_x86_64* *aarch64* *ppc64* *s390x*' ||
-              matrix.os == 'macos-15-intel' && '*macosx_arm64* *aarch64* *ppc64* *s390x*' ||
-              '*aarch64* *arm64* *ppc64* *s390x*'
+              matrix.os == 'macos-14' && 'arm64' ||
+              matrix.os == 'macos-15-intel' && 'x86_64' ||
+              'auto'
             }}
 
       - name: "Upload build artifacts (${{ matrix.os }}, py${{ matrix.python-version }})"

cibuildwheel.toml

@@ -11,8 +11,7 @@ skip = [
   "pp*",
 ]
 
-macos.archs = ["x86_64", "arm64"]
-
+# Architecture is set per-runner in the workflow file to avoid cross-compilation
 # GSL libraries from Homebrew require macOS 14.0 minimum
 macos.environment = {MACOSX_DEPLOYMENT_TARGET = "14.0"}
 
@@ -28,14 +27,6 @@ macos.before-build = [
 ]
 
 
-test-skip = [
-  "*aarch64*",
-  "*arm64*",
-  "*ppc64*",
-  "*s390x*",
-]
-
-
 linux.before-test = [
   "pip install 'biopython' 'matplotlib' 'numpy<2' 'pandas' 'pygments' 'scipy'"
 ]