BUG: Disable parallel cythonize on Windows (GH 30214) (#30585)

Author: Dr-Irv

ci/azure/windows.yml

@@ -34,7 +34,7 @@ jobs:
     - bash: |
         source activate pandas-dev
         conda list
-        python setup.py build_ext -q -i
+        python setup.py build_ext -q -i -j 4
         python -m pip install --no-build-isolation -e .
       displayName: 'Build'
 

doc/source/whatsnew/v1.0.0.rst

@@ -980,7 +980,8 @@ Other
 - Fixed :class:`IntegerArray` returning ``inf`` rather than ``NaN`` for operations dividing by 0 (:issue:`27398`)
 - Fixed ``pow`` operations for :class:`IntegerArray` when the other value is ``0`` or ``1`` (:issue:`29997`)
 - Bug in :meth:`Series.count` raises if use_inf_as_na is enabled (:issue:`29478`)
-- Bug in :class:`Index` where a non-hashable name could be set without raising ``TypeError`` (:issue:29069`)
+- Bug in :class:`Index` where a non-hashable name could be set without raising ``TypeError`` (:issue:`29069`)
+
 
 .. _whatsnew_1000.contributors:
 

setup.py

@@ -526,6 +526,11 @@ def maybe_cythonize(extensions, *args, **kwargs):
     elif parsed.j:
         nthreads = parsed.j
 
+    # GH#30356 Cythonize doesn't support parallel on Windows
+    if is_platform_windows() and nthreads > 0:
+        print("Parallel build for cythonize ignored on Windows")
+        nthreads = 0
+
     kwargs["nthreads"] = nthreads
     build_ext.render_templates(_pxifiles)
     return cythonize(extensions, *args, **kwargs)