Try Windows using conda

Author: WillAyd

.github/workflows/python.yml

@@ -288,11 +288,23 @@ jobs:
         env:
           # We can invalidate the current cache by updating this.
           CACHE_VERSION: "2025-09-16.1"
+      - name: Install and setup micromamba
+        shell: cmd
+        env:
+            MAMBA_ROOT_PREFIX: "C:\\micromamba"
+        run: |
+          curl -L -o micromamba.tar.bz2 https://micro.mamba.pm/api/micromamba/win-64/latest
+          tar xf micromamba.tar.bz2
+          mv "Library\bin\micromamba.exe" micromamba.exe
+          .\micromamba.exe shell init -s cmd -r %MAMBA_ROOT_PREFIX%
+          micromamba create -n pyarrow-dev -f ".\ci\conda_env_python.txt" -y
       - name: Build Arrow C++ and PyArrow
         shell: cmd
         run: |
-          call "ci\scripts\python_build.bat" %cd% "${{ steps.path-info.outputs.usr-windows-dir }}"
+          micromamba activate pyarrow-dev
+          call "ci\scripts\python_build.bat" %cd% %CONDA_PREFIX%
       - name: Test PyArrow
         shell: cmd
         run: |
+          micromamba activate pyarrow-dev
           call "ci\scripts\python_test.bat" %cd%

ci/scripts/python_build.bat

@@ -198,15 +198,9 @@ pushd %SOURCE_DIR%\python
 @REM Install Python build dependencies
 %PYTHON_CMD% -m pip install --upgrade pip || exit /B 1
 %PYTHON_CMD% -m pip install -r requirements-build.txt || exit /B 1
-%PYTHON_CMD% -m pip install build delvewheel || exit /B 1
-
-@REM by default, CMake installs .lib import libs to lib and .dll libs to bin
-@REM delvewheel requires these to be side-by-side to properly vendor
-@REM https://github.com/adang1345/delvewheel/issues/66
-copy %CMAKE_INSTALL_PREFIX%\lib\*.lib %CMAKE_INSTALL_PREFIX%\bin\
 
 @REM Build PyArrow
-%PYTHON_CMD% -m build --wheel . --no-isolation ^
+%PYTHON_CMD% -m pip install --no-deps --no-build-isolation -vv . ^
     -Csetup-args="-Dbuildtype=%MESON_BUILD_TYPE%" ^
     -Csetup-args="-Dacero=%PYARROW_WITH_ACERO%" ^
     -Csetup-args="-Ddataset=%PYARROW_WITH_DATASET%" ^
@@ -219,7 +213,5 @@ copy %CMAKE_INSTALL_PREFIX%\lib\*.lib %CMAKE_INSTALL_PREFIX%\bin\
     -Csetup-args="-Dparquet_require_encryption=%PYARROW_WITH_PARQUET_ENCRYPTION%" ^
     -Csetup-args="-Dsubstrait=%PYARROW_WITH_SUBSTRAIT%" ^
     -Csetup-args="-Ds3=%PYARROW_WITH_S3%" || exit /B 1
-%PYTHON_CMD% -m delvewheel repair --ignore-existing --no-mangle-all --include-imports dist\* || exit /B 1
-%PYTHON_CMD% -m pip install --no-index --find-links .\wheelhouse\ pyarrow || exit /B 1
 
 popd

python/pyarrow/__init__.py

@@ -393,12 +393,6 @@ def get_library_dirs():
     package_cwd = _os.path.dirname(__file__)
     library_dirs = [package_cwd]
 
-    # delvewheel creates a top level pyarrow.libs to vendor external shared libraries
-    if _os.name == "nt":
-        library_dirs.append(
-            _os.path.join(_os.path.dirname(package_cwd), "pyarrow.libs")
-        )
-
     def append_library_dir(library_dir):
         if library_dir not in library_dirs:
             library_dirs.append(library_dir)