Protobuf: How to import .proto file in different package correctly?

[AlexLuya]

I have two packages like this

com.abc.
         protobuf.
                    share.proto
         depart.
                    detect.proto 

and the conent of share.proto like this:

syntax = "proto3";
package com.adc.protobuf;
message Test{}

and the content of detect.proto like this:

syntax = "proto3";
package com.adc.depart;
import "com/abc/protobuf/share.proto"

and compile share.proto in it's dir like this:

protoc -I=. --python_out=. share.proto

then compile detect.proto in it's dir like this:

protoc -I=/pathToSrcDir/ -I=. --python_out=. detect.proto

and

pathToSrcDir has been added to PYTHONPATH,all compilations work fine,but when run a python script which

from com.abc.depart import detect_pb2

got this error

TypeError: Couldn't build proto file into descriptor pool!
Invalid proto descriptor for file "detect.proto":
  detect.proto: Import "com/abc/protobuf/share.proto" has not been loaded.
  com.abc.depert.XClass.ymethod: "com.abc.protobuf.Test" seems to be defined in "share.proto", which is not imported by "detect.proto".  To use it here, please add the necessary import.

How to solve this import problem?

[arthur-tacca]

(Note: I'm not a protobuf developer, I just came across your report.)

I think your inconsistent use of includes is the root of the problem. You have two choices, and you need to pick one and stick to it:

1. Are the files in no particular package? In that case they are ./share.proto and ./detect.proto (as when using protoc -I. from within com/abc/depart/), and from Python use import share_pb2 and import detect_pb2.
2. Or are they com.abc.<something> packages? In that case they are com/abc/protobuf/share.proto and com/abc/depart/detect.proto (as when using protoc -I/pathToSrcDir and in "com/abc/protobuf/share.proto"), and from Python use import com.abc.protobuf.share_pb2 and import com.abc.depart.detect_pb2.

I suspect you probably want the second one, so I'll just cover that. Then the import in detect.proto is fine, but you need to change your protoc commands like this:

cd /pathToSrcDir/
protoc -I. --python_out=. com/abc/protobuf/share.proto 
protoc -I. --python_out=. com/abc/depart/detect.proto

You could even merge the two commands:

cd /pathToSrcDir/
protoc -I. --python_out=. com/abc/protobuf/share.proto com/abc/depart/detect.proto

Make sure you have added /pathToSrc/ to your PYTHONPATH, NOT /pathToSrc/com/abc/protobuf.

By the way, you can always use a different directory for your protos and Python files. For example, if you have a proto/ directory and a src/ directory, use this command (and add /pathToProjectDir/src to your PYTHONPATH):

cd /pathToProjectDir/
protoc -Iproto --python_out=src proto/com/abc/protobuf/share.proto proto/com/abc/depart/detect.proto

[AlexLuya]

Your solution works,thanks very much