Importing onnxruntime together with onnxmltools casues protobuf error

[janjagusch]

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

Issue:

When importing onnxruntime and onnxmltools into the same Python session, protobuf throws an error. It does not matter in which order you import the two packages.

$ python
Python 3.8.8 | packaged by conda-forge | (default, Feb 20 2021, 16:22:27) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import onnxruntime
>>> import onnxmltools
[libprotobuf ERROR google/protobuf/descriptor_database.cc:641] File already exists in database: onnx/onnx-ml.proto
[libprotobuf FATAL google/protobuf/descriptor.cc:1371] CHECK failed: GeneratedDatabase()->Add(encoded_file_descriptor, size): 
terminate called after throwing an instance of 'google::protobuf::FatalException'
  what():  CHECK failed: GeneratedDatabase()->Add(encoded_file_descriptor, size): 
Aborted (core dumped)
(sd-pricing-r) root@192.168.146.87 (docker)
$ python
Python 3.8.8 | packaged by conda-forge | (default, Feb 20 2021, 16:22:27) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import onnxmltools
>>> import onnxruntime
[libprotobuf ERROR google/protobuf/descriptor_database.cc:641] File already exists in database: onnx/onnx-ml.proto
[libprotobuf FATAL google/protobuf/descriptor.cc:1371] CHECK failed: GeneratedDatabase()->Add(encoded_file_descriptor, size): 
terminate called after throwing an instance of 'google::protobuf::FatalException'
  what():  CHECK failed: GeneratedDatabase()->Add(encoded_file_descriptor, size): 
Aborted (core dumped)

Environment (conda list):

``` $ conda list ```

Details about conda and system ( conda info ):

``` $ conda info ```