macOS e2e tests fail due to multi-processing

[powderluv]

build with:

(mlir_venv) (base) anush@denali torch-mlir % cmake -GNinja -Bbuild   -DCMAKE_BUILD_TYPE=Release   -DCMAKE_C_COMPILER=clang   -DCMAKE_CXX_COMPILER=clang++   -DPython3_FIND_VIRTUALENV=ONLY   -DLLVM_ENABLE_PROJECTS=mlir   -DLLVM_EXTERNAL_PROJECTS="torch-mlir;torch-mlir-dialects"   -DLLVM_EXTERNAL_TORCH_MLIR_SOURCE_DIR=`pwd`   -DLLVM_EXTERNAL_TORCH_MLIR_DIALECTS_SOURCE_DIR=`pwd`/externals/llvm-external-projects/torch-mlir-dialects   -DMLIR_ENABLE_BINDINGS_PYTHON=ON   -DLLVM_TARGETS_TO_BUILD=host externals/llvm-project/llvm  && cmake --build build --target check-torch-mlir-python

Fails with the following on an intel mac system

********************
********************
Failed Tests (6):
  TORCH_MLIR_PYTHON :: torchscript_e2e_test/basic.py
  TORCH_MLIR_PYTHON :: torchscript_e2e_test/compilation_failure.py
  TORCH_MLIR_PYTHON :: torchscript_e2e_test/error_reports.py
  TORCH_MLIR_PYTHON :: torchscript_e2e_test/non_tensor_values.py
  TORCH_MLIR_PYTHON :: torchscript_e2e_test/runtime_failure.py
  TORCH_MLIR_PYTHON :: torchscript_e2e_test/submodule.py


Testing Time: 2.89s
  Passed: 6
  Failed: 6

[silvasean]

What is the error message?

[powderluv]

The error is:

                                                                                                                                                                                                                                             
********************                                                                                                                 
FAIL: TORCH_MLIR_PYTHON :: torchscript_e2e_test/error_reports.py (11 of 12)                                                          
******************** TEST 'TORCH_MLIR_PYTHON :: torchscript_e2e_test/error_reports.py' FAILED ********************                   
Script:                                                                                                                              
--                                                                                                                                   
: 'RUN: at line 6';   /Users/anush/github/torch-mlir/mlir_venv/bin/python3.10 /Users/anush/github/torch-mlir/python/test/torchscript_e2e_test/error_reports.py | /Users/anush/github/torch-mlir/build/bin/FileCheck /Users/anush/github/torch-mlir/python/test/torchscript
_e2e_test/error_reports.py                                                                                                                                                                                                                                                
--                                                                                                                                   
Exit Code: 2                                                                                                                         
                                                                                                                                     
Command Output (stderr):                                                                                                             
--                                                                                                                                                                                                                                                                        
Traceback (most recent call last):                                                                                                   
  File "/Users/anush/github/torch-mlir/python/test/torchscript_e2e_test/error_reports.py", line 161, in <module>                                                                                                                                                          
    main()                                                                                                                           
  File "/Users/anush/github/torch-mlir/python/test/torchscript_e2e_test/error_reports.py", line 156, in main                                                                                                                                                              
    results = run_tests(GLOBAL_TEST_REGISTRY, config)                                                                                                                                                                                                                     
  File "/Users/anush/github/torch-mlir/build/tools/torch-mlir/python_packages/torch_mlir/torch_mlir_e2e_test/torchscript/framework.py", line 360, in run_tests
    run_workers_in_parallel(tests_queue, worker)                                                                                     
  File "/Users/anush/github/torch-mlir/build/tools/torch-mlir/python_packages/torch_mlir/torch_mlir_e2e_test/torchscript/framework.py", line 325, in run_workers_in_parallel
    p.start()                                                                                                                                                                                                                                                             
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/process.py", line 121, in start
    self._popen = self._Popen(self)                                                                                                  
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/context.py", line 224, in _Popen           
    return _default_context.get_context().Process._Popen(process_obj)                                                                
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/context.py", line 284, in _Popen           
    return Popen(process_obj)                                     
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/popen_spawn_posix.py", line 32, in __init__ 
    super().__init__(process_obj)                                                                                                    
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/popen_fork.py", line 19, in __init__       
    self._launch(process_obj)                                     
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/popen_spawn_posix.py", line 47, in _launch
    reduction.dump(process_obj, fp)                      
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/multiprocessing/reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)                                                                                                                                                                                                                              
AttributeError: Can't pickle local object 'run_tests.<locals>.worker'                                                                                                                                                                                                     
FileCheck error: '<stdin>' is empty.    
FileCheck command line:  /Users/anush/github/torch-mlir/build/bin/FileCheck /Users/anush/github/torch-mlir/python/test/torchscript_e2e_test/error_reports.py
                                                                                                                                                                                                                                                                          
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