File does not reside within any path specified using --proto_path (or -I). You
must specify a --proto_path which encompasses this file. Note that the
proto_path must be an exact prefix of the .proto file names -- protoc is too
dumb to figure out when two paths (e.g. absolute and relative) are equivalent
(it's harder than you think).


https://github.com/protocolbuffers/protobuf/blob/1bc2c6352acadf5192c53fce4755553b656360e9/src/google/protobuf/compiler/command_line_interface.cc#L1879