Wheels: ARM64 builders for Linux & Windows (#1909)

* Wheels: ARM64 builders for Linux (aarch64) & Windows (ARM64)

Travis-CI is dead; it was the only builder for Linux aarch64 (and ppc64le)
wheels. GitHub now offers free native ARM runners for public repos, so move
Linux ARM wheel production into build.yml and add Windows ARM64 (new platform).

build.yml:
- Linux aarch64 on ubuntu-24.04-arm: full parity with x86_64 (cp310-cp314,
  many+musl, ADIOS2 ON), reuses library_builders.sh unchanged (native aarch64
  needs no SIMD/cross tweaks; blosc2 auto-selects NEON, HDF5 builds natively).
- Windows ARM64 on windows-11-arm: cp311-cp314 (CPython win_arm64 exists only
  from 3.11+, no PyPy). First cut ships HDF5 + JSON only (ADIOS2 OFF), like the
  win32/i686 legs, to avoid an unproven ADIOS2-on-ARM64 build.
- Smoke test: derive the ADIOS2 expectation from matrix.env.ADIOS2 instead of
  process bitness, so a 64-bit ARM wheel without ADIOS2 passes; also makes the
  i686/win32 legs explicit.
- Retarget the retired Travis aarch64/ppc64le matrix comments.

library_builders.bat:
- Gate the ADIOS2 dependency chain (SQLite3, ZFP, C-Blosc2, ADIOS2) behind
  openPMD_CMAKE_openPMD_USE_ADIOS2==ON (visible in the before-build step); keep
  zlib + HDF5 unconditional. Windows ARM64 builds only zlib + HDF5; AMD64
  unchanged (win32 stops building the ADIOS2 stack it already discarded).

.travis.yml:
- Sync to the current post4 patch and cibuildwheel 4.1.0 (kept as reference;
  Travis no longer runs).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Remove Inline Comments

Historic character comments are confusing and unnecessary.

Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>

* Wheels: fix Windows ARM64 CMake platform (-A ARM64)

The first windows-11-arm run failed: openPMD's setup.py picks the Visual
Studio generator platform from interpreter bitness only
(`if sys.maxsize > 2**32: -A x64`), so on win-arm64 (64-bit interpreter,
ARM arch) it passed `-A x64`. That mis-targeted the build and find_package
(Python) then failed ("Could NOT find Python ... Interpreter"). The explicit
-A also overrode any CMAKE_GENERATOR_PLATFORM env (which is why win32 works:
its 32-bit interpreter skips the branch and lets the env drive -A).

- setup-py-windows-arm64-platform.patch: honor CMAKE_GENERATOR_PLATFORM from
  the environment for -A, falling back to the existing x64/interpreter logic.
- build.yml: add the patch to COMMON_PATCHES and set
  CMAKE_GENERATOR_PLATFORM=ARM64 on the windows-11-arm leg.

Dependency builds (zlib + HDF5) and the ADIOS2-chain gating already worked on
ARM64; this only fixes the openPMD wheel's own configure step.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Wheels: valid artifact name for Windows ARM64 leg

With the -A ARM64 fix the windows-11-arm wheels build and pass tests (HDF5 +
JSON round-trip, 0 external deps), but the job failed at upload: the artifact
name wheels-${os}-${build||arch} interpolated this leg's build glob
("cp311-* cp312-* ..."), and '*'/spaces are invalid in an artifact name.

Add an optional matrix.artifact override (default: build || arch) and set it to
"ARM64" for the windows-11-arm leg -> wheels-windows-11-arm-ARM64.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Artifact name Update

Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ax3l

.github/workflows/build.yml

@@ -7,6 +7,7 @@ env:
   COMMON_PATCHES: >
     .github/setup-py-version-post4.patch
     .github/setup-py-windows-cmake-options.patch
+    .github/setup-py-windows-arm64-platform.patch
     .github/python-hide-symbols.patch
     .github/python-wasm-side-module.patch
     .github/hdf5-dont-atexit-emscripten.patch
@@ -24,6 +25,7 @@ jobs:
         #   platform     CIBW_PLATFORM                 (default auto)
         #   build        CIBW_BUILD                    (default *, i.e. all)
         #   patches      space-separated setup patches (default: Windows one)
+        #   artifact     artifact-name suffix override (default: build || arch)
         #   sdist        also build + upload the sdist artifact (default: off)
         include:
           - os: ubuntu-22.04
@@ -38,11 +40,11 @@ jobs:
             env:
               ADIOS2: "OFF"
 
-          # builds faster on Travis-CI:
-          #- os: ubuntu-20.04
-          #  arch: "aarch64"
+          - os: ubuntu-24.04-arm
+            arch: "aarch64"
 
-          # builds faster on Travis-CI:
+          # ppc64le was only ever built on the (now retired) Travis-CI; there is no
+          # free GitHub-hosted ppc64le runner, so these wheels are no longer produced.
           #- os: ubuntu-20.04
           #  arch: "ppc64le"
 
@@ -63,6 +65,14 @@ jobs:
               CMAKE_GENERATOR_PLATFORM: "Win32"
               ADIOS2: "OFF"   # 32-bit: no 32-bit ADIOS2 CI; BP read segfaults (see i686)
 
+          - os: windows-11-arm
+            arch: "ARM64"
+            build: "cp311-* cp312-* cp313-* cp314-*"
+            artifact: "WinArm64"
+            env:
+              ADIOS2: "OFF"
+              CMAKE_GENERATOR_PLATFORM: "ARM64"
+
           - os: macos-15-intel
             arch: "x86_64"
             env:
@@ -235,8 +245,8 @@ jobs:
         CIBW_TEST_REQUIRES_PYODIDE: numpy
         CIBW_TEST_COMMAND: >
           python {project}/.github/check_wheel_libs.py &&
-          python -c "import sys, openpmd_api as io; v = io.variants;
-          need_adios2 = sys.maxsize > 2**32;
+          python -c "import openpmd_api as io; v = io.variants;
+          need_adios2 = '${{ matrix.env.ADIOS2 || 'ON' }}' == 'ON';
           assert v['hdf5'] and v['json'] and (v['adios2'] or not need_adios2), v;
           print('openPMD', io.__version__, dict(v))" &&
           python {project}/.github/smoke_roundtrip.py
@@ -257,8 +267,9 @@ jobs:
       name: Publish as GitHub artifact
       with:
         # Include matrix.build so the two wasm legs (cp313 / cp314, which share
-        # os=ubuntu-24.04 + arch=wasm32) get DISTINCT artifact names.
-        name: wheels-${{ matrix.os }}-${{ matrix.build || matrix.arch }}
+        # os=ubuntu-24.04 + arch=wasm32) get DISTINCT artifact names. matrix.artifact
+        # overrides it where build holds glob chars invalid in a name (Windows ARM64).
+        name: wheels-${{ matrix.os }}-${{ matrix.artifact || matrix.build || matrix.arch }}
         path: ./wheelhouse
         overwrite: true
 

.travis.yml

@@ -134,12 +134,12 @@ install:
   - git clone --branch ${OPENPMD_GIT_REF} --depth 1 https://github.com/openPMD/openPMD-api.git src
   - cp library_builders.sh list_library_deps.py check_wheel_libs.py smoke_roundtrip.py src/.github/
   # Wheels-only re-release: bump the package version (same source).
-  - (cd src && git apply ../setup-py-version-post2.patch)
+  - (cd src && git apply ../setup-py-version-post4.patch)
   # Keep statically-embedded deps (HDF5/ADIOS2/openPMD) private so the wheel can
   # be co-loaded with another extension that also embeds them (ImpactX/WarpX).
   - (cd src && git apply ../python-hide-symbols.patch)
   - python -m pip install --upgrade pip setuptools wheel
-  - python -m pip install cibuildwheel==3.2.1
+  - python -m pip install cibuildwheel==4.1.0
   # twine & cryptography: see
   #   https://github.com/scikit-build/cmake-python-distributions/blob/4730aeee240917303f293dffc89a8d8d5a4787c4/requirements-deploy.txt
   #   https://github.com/pyca/cryptography/issues/6086

library_builders.bat

@@ -288,10 +288,14 @@ exit /b 0
 :main
 call :install_buildessentials
 call :build_zlib
-call :build_sqlite
-:: build_bzip2
-:: build_szip
-call :build_zfp
-call :build_blosc2
 call :build_hdf5
-call :build_adios2
+
+rem ADIOS2 and its exclusive dependencies
+if /I "%openPMD_CMAKE_openPMD_USE_ADIOS2%"=="ON" (
+  call :build_sqlite
+  rem build_bzip2
+  rem build_szip
+  call :build_zfp
+  call :build_blosc2
+  call :build_adios2
+)

setup-py-windows-arm64-platform.patch

@@ -0,0 +1,18 @@
+diff --git a/setup.py b/setup.py
+index e44e942..0000001 100644
+--- a/setup.py
++++ b/setup.py
+@@ -104,8 +104,11 @@
+                     os.path.join(extdir, "openpmd_api")
+                 )
+             ]
+-            if sys.maxsize > 2**32:
+-                cmake_args += ['-A', 'x64']
++            generator_platform = os.environ.get("CMAKE_GENERATOR_PLATFORM")
++            if generator_platform:
++                cmake_args += ['-A', generator_platform]
++            elif sys.maxsize > 2**32:
++                cmake_args += ['-A', 'x64']
+             build_args += ['--', '/m']
+         else:
+             cmake_args += ['-DCMAKE_BUILD_TYPE=' + cfg]