Remove macOS Intel support and update Ubuntu testing

- PyTorch officially discontinued macOS Intel (x86_64) support after version 2.2.2
- Remove macOS Intel from CI testing matrix (was causing wheel availability errors)
- Constrain macOS Intel to PyTorch 2.2.x in pyproject.toml for legacy support
- Replace Ubuntu 20.04 with Ubuntu 24.04 for more current testing
- Update test summary to reflect supported platforms
- Users on macOS Intel should use PyTorch 2.2.2 or upgrade to ARM64 hardware

References:
- pytorch/pytorch#114602
- https://discuss.pytorch.org/t/pytorch-2-6-0-installation-on-2019-macbook-intel/218576

Author: orlandocloss

.github/workflows/cross-platform-test.yml

@@ -24,13 +24,8 @@ jobs:
             python-version: "3.12"
             platform-name: "Windows-py312"
 
-          # macOS x86_64 (Intel)
-          - os: macos-13  # Intel-based
-            python-version: "3.10"
-            platform-name: "macOS-Intel-py310"
-          - os: macos-13
-            python-version: "3.11"
-            platform-name: "macOS-Intel-py311"
+          # NOTE: macOS Intel (x86_64) REMOVED - PyTorch discontinued support after 2.2.2
+          # Users on macOS Intel should use PyTorch 2.2.2 or switch to ARM64 hardware
 
           # macOS ARM64 (Apple Silicon)
           - os: macos-14  # Apple Silicon
@@ -44,9 +39,9 @@ jobs:
             platform-name: "macOS-ARM64-py312"
 
           # Linux x86_64
-          - os: ubuntu-20.04
+          - os: ubuntu-24.04
             python-version: "3.10"
-            platform-name: "Linux-py310-ubuntu20"
+            platform-name: "Linux-py310-ubuntu24"
           - os: ubuntu-22.04
             python-version: "3.11"
             platform-name: "Linux-py311-ubuntu22"
@@ -318,12 +313,14 @@ jobs:
           echo "🎉 SUCCESS: All platforms passed!"
           echo ""
           echo "✅ Windows (Python 3.10, 3.11, 3.12)"
-          echo "✅ macOS Intel (Python 3.10, 3.11)"
           echo "✅ macOS Apple Silicon (Python 3.10, 3.11, 3.12)"
           echo "✅ Linux Ubuntu (Python 3.10, 3.11, 3.12)"
           echo ""
-          echo "Your bplusplus package is compatible across all platforms!"
-          echo "Users can safely install on Windows, macOS, and Linux."
+          echo "ℹ️  Note: macOS Intel (x86_64) excluded - PyTorch discontinued support"
+          echo "   macOS Intel users should use PyTorch 2.2.2 or upgrade to ARM64 hardware"
+          echo ""
+          echo "Your bplusplus package is compatible across all supported platforms!"
+          echo "Users can safely install on Windows, macOS ARM64, and Linux."
         else
           echo "❌ FAILURE: Some platform tests failed"
           echo ""

pyproject.toml

@@ -23,13 +23,13 @@ pillow = [
     # Linux - most flexible
     {version = ">=10.0.0,<12.0.0", markers = "sys_platform == 'linux'"}
 ]
-# PyTorch with platform-specific compatibility to avoid wheel availability issues
+# PyTorch with platform-specific compatibility to handle discontinued macOS Intel support
 torch = [
     # Windows - stable version range
     {version = ">=2.0.0,<2.8.0", markers = "sys_platform == 'win32'"},
-    # macOS Intel - more conservative range due to wheel availability
-    {version = ">=2.0.0,<2.7.0", markers = "sys_platform == 'darwin' and platform_machine == 'x86_64'"},
-    # macOS ARM64 - broader range, better wheel support
+    # macOS Intel - DISCONTINUED after PyTorch 2.2.2, use last supported version
+    {version = ">=2.2.0,<2.3.0", markers = "sys_platform == 'darwin' and platform_machine == 'x86_64'"},
+    # macOS ARM64 - full support, broader range
     {version = ">=2.0.0,<2.8.0", markers = "sys_platform == 'darwin' and platform_machine == 'arm64'"},
     # Linux - most flexible, best wheel support
     {version = ">=2.0.0,<2.8.0", markers = "sys_platform == 'linux'"}