[Go] Panic when importing different versions of Arrow Flight in the same project (v12, v13)

[phillipleblanc]

Describe the bug, including details regarding any error messages, version, and platform.

Importing both github.com/apache/arrow/go/v12/arrow/flight and github.com/apache/arrow/go/v13/arrow/flight into the same project causes a panic on startup due to a protobuf namespace conflict:

panic: proto: file "Flight.proto" is already registered
	previously from: "github.com/apache/arrow/go/v12/arrow/flight/internal/flight"
	currently from:  "github.com/apache/arrow/go/v13/arrow/flight/internal/flight"
See https://protobuf.dev/reference/go/faq#namespace-conflict


goroutine 1 [running]:
google.golang.org/protobuf/reflect/protoregistry.glob..func1({0x3f49720?, 0xc000bfa010?}, {0x3f49720?, 0xc000bfa060})
	/go/pkg/mod/google.golang.org/protobuf@v1.31.0/reflect/protoregistry/registry.go:56 +0x1e5
google.golang.org/protobuf/reflect/protoregistry.(*Files).RegisterFile(0xc000012810, {0x3f9a3f8?, 0xc0013281c0?})
	/go/pkg/mod/google.golang.org/protobuf@v1.31.0/reflect/protoregistry/registry.go:130 +0x3a6
google.golang.org/protobuf/internal/filedesc.Builder.Build({{0x358b83d, 0x3b}, {0x5af6de0, 0xb4d, 0xb4d}, 0x2, 0x13, 0x0, 0x1, {0x3f567a8, ...}, ...})
	/go/pkg/mod/google.golang.org/protobuf@v1.31.0/internal/filedesc/build.go:112 +0x1d6
google.golang.org/protobuf/internal/filetype.Builder.Build({{{0x358b83d, 0x3b}, {0x5af6de0, 0xb4d, 0xb4d}, 0x2, 0x13, 0x0, 0x1, {0x0, ...}, ...}, ...})
	/go/pkg/mod/google.golang.org/protobuf@v1.31.0/internal/filetype/build.go:138 +0x199
github.com/apache/arrow/go/v13/arrow/flight/internal/flight.file_Flight_proto_init()
	/go/pkg/mod/github.com/apache/arrow/go/v13@v13.0.0/arrow/flight/internal/flight/Flight.pb.go:1792 +0x1b8
github.com/apache/arrow/go/v13/arrow/flight/internal/flight.init.0()
	/go/pkg/mod/github.com/apache/arrow/go/v13@v13.0.0/arrow/flight/internal/flight/Flight.pb.go:1543 +0xf

Component(s)

Go

[zeroshade]

@phillipleblanc So, the only thing I can think of to try to solve this one would be to make the generated code from the .proto files a separate module and give it it's own go.mod file. That should let all the Arrow versions rely on a single version of the generated code. I'll take a look into seeing what the best route forward here would be.