pcaspy and p4p incompatibility

[jacquelinegarrahan]

• I read the conda-forge documentation and could not find the solution for my problem there.

Issue:

For our lume-epics package, we use both pcaspy==0.7.3 and p4p==3.5.4. Using the conda-forge distributions, I've run into errors on Windows 10. Namely, loading issues on import, with import order impacting error origin:

>>> import pcaspy
>>> import p4p
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\jgarra\Miniconda3\envs\pcaspy-test\lib\site-packages\p4p\__init__.py", line 11, in <module>
    from .wrapper import Value, Type
  File "C:\Users\jgarra\Miniconda3\envs\pcaspy-test\lib\site-packages\p4p\wrapper.py", line 5, in <module>
    from ._p4p import TypeBase, ValueBase
ImportError: DLL load failed while importing _p4p: The specified procedure could not be found.

And, with p4p first:

>>> import p4p
>>> import pcaspy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\jgarra\Miniconda3\envs\pcaspy-test\lib\site-packages\pcaspy\__init__.py", line 1, in <module>
    from .driver import Driver, SimpleServer, PVInfo, SimplePV
  File "C:\Users\jgarra\Miniconda3\envs\pcaspy-test\lib\site-packages\pcaspy\driver.py", line 1, in <module>
    from . import cas
  File "C:\Users\jgarra\Miniconda3\envs\pcaspy-test\lib\site-packages\pcaspy\cas.py", line 13, in <module>
    from . import _cas
ImportError: DLL load failed while importing _cas: The specified procedure could not be found.

I've tested this over a matrix using the pip installations for both, conda installation for both and either, and the conda-forge pcaspy introduces the behavior.

Environment (conda list):

$ conda list
ca-certificates           2021.10.8            h5b45459_0    conda-forge
cython                    0.29.24          py38h885f38d_0    conda-forge
epics-base                7.0.5.0              h0e60522_0    conda-forge
epicscorelibs             7.0.4.99.1.2     py38h885f38d_0    conda-forge
intel-openmp              2021.4.0          h57928b3_3556    conda-forge
libblas                   3.9.0              12_win64_mkl    conda-forge
libcblas                  3.9.0              12_win64_mkl    conda-forge
liblapack                 3.9.0              12_win64_mkl    conda-forge
mkl                       2021.4.0           h0e2418a_729    conda-forge
nose                      1.3.7                   py_1006    conda-forge
numpy                     1.21.3           py38h089cfbf_0    conda-forge
openssl                   3.0.0                h8ffe710_1    conda-forge
p4p                       3.5.3            py38h4c96930_0    conda-forge
pcaspy                    0.7.3            py38h5d928e2_0    conda-forge
perl                      5.32.1.1        1_h57928b3_strawberry    conda-forge
pip                       21.3.1             pyhd8ed1ab_0    conda-forge
ply                       3.11                       py_1    conda-forge
python                    3.8.12          h900ac77_2_cpython    conda-forge
python_abi                3.8                      2_cp38    conda-forge
setuptools                58.4.0           py38haa244fe_1    conda-forge
sqlite                    3.36.0               h8ffe710_2    conda-forge
tbb                       2021.4.0             h2d74725_0    conda-forge
ucrt                      10.0.20348.0         h57928b3_0    conda-forge
vc                        14.2                 hb210afc_5    conda-forge
vs2015_runtime            14.29.30037          h902a5da_5    conda-forge
wheel                     0.37.0             pyhd8ed1ab_1    conda-forge

Details about conda and system ( conda info ):

$ conda info
     active environment : pcaspy-test
    active env location : C:\Users\jgarra\Miniconda3\envs\pcaspy-test
            shell level : 5
       user config file : C:\Users\jgarra\.condarc
 populated config files : C:\Users\jgarra\.condarc
          conda version : 4.10.3
    conda-build version : not installed
         python version : 3.9.5.final.0
       virtual packages : __win=0=0
                          __archspec=1=x86_64
       base environment : C:\Users\jgarra\Miniconda3  (writable)
      conda av data dir : C:\Users\jgarra\Miniconda3\etc\conda
  conda av metadata url : None
           channel URLs : https://conda.anaconda.org/conda-forge/win-64
                          https://conda.anaconda.org/conda-forge/noarch
                          https://repo.anaconda.com/pkgs/main/win-64
                          https://repo.anaconda.com/pkgs/main/noarch
                          https://repo.anaconda.com/pkgs/r/win-64
                          https://repo.anaconda.com/pkgs/r/noarch
                          https://repo.anaconda.com/pkgs/msys2/win-64
                          https://repo.anaconda.com/pkgs/msys2/noarch
          package cache : C:\Users\jgarra\Miniconda3\pkgs
                          C:\Users\jgarra\.conda\pkgs
                          C:\Users\jgarra\AppData\Local\conda\conda\pkgs
       envs directories : C:\Users\jgarra\Miniconda3\envs
                          C:\Users\jgarra\.conda\envs
                          C:\Users\jgarra\AppData\Local\conda\conda\envs
               platform : win-64
             user-agent : conda/4.10.3 requests/2.25.1 CPython/3.9.5 Windows/10 Windows/10.0.14393
          administrator : False
             netrc file : None
           offline mode : False