CI: Pin PYTEST_WORKERS=1 for Windows builds due to memory errors (#47318)

* CI/DEBUG: Windows 3.9 memory error

* Try skipping some suspicious tests

* Try skipping this hanging test

* Check if can run okay on single process

* Trigger CI

* run in parallel again

* Log even more

* a little less debugging

* dont try new pyarrow

* Try one more time with pyarrow<8, simple

* Comment out pyarrow hack

* Restart, show setup and full traceback

* Also try the older windows

* generate debug log again

* change to latest

* dump log if failure

* Create separate log per os/version

* See if it was any dependencies bumped recently

* See if same errors happen without dependencies pinnning

* Skip plotting tests on windows

* Skip in frame as well

* Trigger another run

* Is it the non-nano?

* skip resample tests

* Just use 1 thread for windows

* Full run

Author: mroeschke

.github/workflows/macos-windows.yml

@@ -15,7 +15,6 @@ on:
 env:
   PANDAS_CI: 1
   PYTEST_TARGET: pandas
-  PYTEST_WORKERS: auto
   PATTERN: "not slow and not db and not network and not single_cpu"
 
 
@@ -36,6 +35,9 @@ jobs:
       # https://github.community/t/concurrecy-not-work-for-push/183068/7
       group: ${{ github.event_name == 'push' && github.run_number || github.ref }}-${{ matrix.env_file }}-${{ matrix.os }}
       cancel-in-progress: true
+    env:
+      # GH 47443: PYTEST_WORKERS > 1 crashes Windows builds with memory related errors
+      PYTEST_WORKERS: ${{ matrix.os == 'macos-latest' && 'auto' || '1' }}
 
     steps:
     - name: Checkout