Support running plugins with go1.24's "go tool" pattern

[nvx]

Instead of running protoc plugins as protoc-gen-tool running them as go tool protoc-gen-tool would allow tool version management to occur within the go.mod file simplifying tool management.

A flag to control the behaviour would make sense

[meling]

Not sure I understand how you would use the flag to replace something like this:

protoc \
	-I . \
	-I `go list -m -f {{.Dir}} github.com/alta/protopatch` \
	-I `go list -m -f {{.Dir}} google.golang.org/protobuf` \
	--go-patch_out=plugin=go,paths=source_relative:. \
	--go-patch_out=plugin=go-grpc,paths=source_relative:. \
	*.proto

[nvx]

Not sure I understand how you would use the flag to replace something like this:

protoc
-I .
-I go list -m -f {{.Dir}} github.com/alta/protopatch
-I go list -m -f {{.Dir}} google.golang.org/protobuf
--go-patch_out=plugin=go,paths=source_relative:.
--go-patch_out=plugin=go-grpc,paths=source_relative:.
*.proto

it's not about managing proto dependencies (I personally use buf for that side of things), but rather about managing the protoc-gen-go tool itself. Check out https://tip.golang.org/doc/modules/managing-dependencies#tools and the Go1.24 release notes for more information about the pattern, but the tldr is it means you wouldn't need to have protoc-gen-* tools installed or manage the version of them and instead which version is used gets managed by the version referenced in the go.mod file. This is super handy for projects with multiple developers as you no longer have to rely on the version installed on their machine when regenerating the protos.

[meling]

I’m aware of the 1.24 tool dependency in go.mod feature. I just didn’t understand how to use the flag to take advantage of it. Could you give a usage example; will it only work with buf?

[nvx]

I’m aware of the 1.24 tool dependency in go.mod feature. I just didn’t understand how to use the flag to take advantage of it. Could you give a usage example; will it only work with buf?

oh you mean how the specific implementation I PR'd in #182 works? if so --go-patch_out=plugin=go,paths=source_relative:. would become --go-patch_out=plugin=go,paths=source_relative,use_go_tool=true:. which would have the effect of running go tool protoc-gen-go instead of protoc-gen-go

It would work both with and without buf, but if you're not using buf then the proto dependency management is up to you still (I imagine your go list example would still work for example)

For buf something like this would work in your buf.gen.yaml:

version: v2
plugins:
  - local: [go,tool,protoc-gen-go-patch]
    out: .
    opt:
      - plugin=go
      - use_go_tool=true

[meling]

FYI, I got it to work without the flag:

version: v2
plugins:
- local: [ "go", "tool", "protoc-gen-go-patch" ]
  out: ./
  opt:
  - plugin=go
  - paths=source_relative
- local: [ "go", "tool", "protoc-gen-connect-go" ]
  out: ./
  opt:
  - paths=source_relative

Not sure why you need the flag...

[nvx]

FYI, I got it to work without the flag:

version: v2
plugins:

• local: [ "go", "tool", "protoc-gen-go-patch" ]
  out: ./
  opt:
  • plugin=go
  • paths=source_relative
• local: [ "go", "tool", "protoc-gen-connect-go" ]
  out: ./
  opt:
  • paths=source_relative
    Not sure why you need the flag...

That is running protoc-gen-protopatch with go tool, but protoc-gen-go isn't running with go tool. Try running what you have without protoc-gen-go in your PATH