Protobuf: [Python] A file with this name is already in the pool.

[rossengeorgiev]

This problem arises from the linux binary wheels for protobuf==3.2.0. Using the pure python implementation works fine.

In my case I proto file that collides with name of proto file from another package. Importing both python packages is not possible as I get this error.

Steps to replicate

Directory tree:

./module1
./module1/messages.proto
./module1/messages_pb2.py
./module1/__init__.py
./module2
./module2/messages.proto
./module2/messages_pb2.py
./module2/__init__.py

./module1/messages.proto

syntax = "proto2";
package module1;

./module2/messages.proto

syntax = "proto2";
package module2;

Trying to import:

python -c "import module1.messages_pb2, module2.messages_pb2"
------
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "module2/messages_pb2.py", line 22, in <module>
    serialized_pb=_b('\n\x0emessages.proto\x12\x07module2')
  File "/home/vagrant/env/local/lib/python2.7/site-packages/google/protobuf/descriptor.py", line 824, in __new__
    return _message.default_pool.AddSerializedFile(serialized_pb)
TypeError: Couldn't build proto file into descriptor pool!
Invalid proto descriptor for file "messages.proto":
  messages.proto: A file with this name is already in the pool.

[feifangit]

I ran into this issue too. I have to make the .proto files in unique file names.

[ndwhelan]

Ran in to this issue. If anyone finds this, I resolved it by running pip uninstall protobuf and then pip install --no-binary protobuf protobuf. That made sure that only the source was installed, and, as mentioned above, for some reason, things work fine in the pure python version.

[trianta2]

I found that doing

export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION='python'

before running my Python code resolved the issue. I got the flag from the bottom of https://developers.google.com/protocol-buffers/docs/reference/python-generated

[xfxyjwf]

The error (file already in pool) indicates an actual problem you need to fix on the .proto files. A simple solution is to put one of the .proto file in a subdirectory.

Right now you can hide the problem by switching to the pure python implementation (which doesn't check conflicts), but that won't really solve the issue. You are going to run into the same problem if you are using a different language, or if we fix the pure python implementation to check conflict as well.

[rossengeorgiev]

@xfxyjwf I think you are confused. The original issue cannot be fixed by doing anything the protos, except renaming the duplicate message.

The pure python implementation uses the directory for namespacing, and that works. Just as described in the documentation https://developers.google.com/protocol-buffers/docs/proto#packages

The problem is that the C++ implementation doesn't do that, nor does it respect the package directive. This issue is not noted in the documentation at all. In fact, the documentation advises on using package in protos (see my example at the top), but that does not work in C++ implementation. So, clearly a bug.

[xfxyjwf]

@rossengeorgiev Can you regenerate the *_pb2.py files by invoking:

$ protoc --python_out=. module1/messages.proto module2/messages.proto

? That should solve the issue you are having. Note that the python import path must match the file path you passed to protoc.

[rossengeorgiev]

I managed to figure out what caused the original issue. The clue was in the error. The descriptor name is derived from the relative path.

serialized_pb=_b('\n\x0emessages.proto\x12\x07module2')

That means I compiled the code by going into each directory and running protoc --python_out=. messages.proto. If I run it as you suggest, or even as protoc --python_out=. module1/messages.proto; protoc --python_out=. module2/messages.proto; it will work regardless. The descriptor name will always be different as it is derived from the relative path.

serialized_pb=_b('\n\x16module1/messages.proto\x12\x07module1')

In addition if we have duplicate messages like so:

./module1/messages.proto

syntax = "proto2";
message mymessage { }

./module2/messages.proto

syntax = "proto2";
message mymessage { }  

If we invoke protoc like so, we get an error and nothing gets compiled.

protoc --python_out=. module2/messages.proto module1/messages.proto
module1/messages.proto:3:9: "mymessage" is already defined in file "module2/messages.proto".

Alternatively, we could do:

 protoc --python_out=. module2/messages.proto
 protoc --python_out=. module1/messages.proto

No error and compiles fine. However we get an error when we try to import in the C++ protobuf package, and no error in the pure one.

$ python -c "import module1.messages_pb2, module2.messages_pb2"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "module2/messages_pb2.py", line 22, in <module>
    serialized_pb=_b('\n\x16module2/messages.proto\"\x0b\n\tmymessage')
  File "/home/vagrant/env/local/lib/python2.7/site-packages/google/protobuf/descriptor.py", line 824, in __new__
    return _message.default_pool.AddSerializedFile(serialized_pb)
TypeError: Couldn't build proto file into descriptor pool!
Invalid proto descriptor for file "module2/messages.proto":
  mymessage: "mymessage" is already defined in file "module1/messages.proto".

At this point we have two options. Use pure python protobuf package, or set package directive in our proto files. I think this covers everything. Thanks @xfxyjwf

[kr-ish]

@rossengeorgiev could you clarify what you mean by "set package directive in our proto files"? I'm having this same issue and I'm trying to solve it without using the pure python protobuf package

[kr-ish]

I was working with tensorflow protos that I was trying to compile and use outside of tensorflow- there were a couple of issues but the main issue seems to have been not making sure I had uninstalled tensorflow and from my python environment entirely because one of my services was using a tf service which was causing the conflict- after I refactored that to not use tf and got rid of tf for good measure, I stopped seeing this issue