cmd/go: `go mod tidy` ignores `go.work` file

[bozaro]

What version of Go are you using (go version)?

$ go version
go version go1.18beta1 linux/amd64

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/bozaro/.cache/go-build"
GOENV="/home/bozaro/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/bozaro/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/bozaro/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go-1.18"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.18/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18beta1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/bozaro/github/go-work-play/tools/go.mod"
GOWORK="/home/bozaro/github/go-work-play/go.work"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build4292218461=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Minimal reproducing repository: https://github.com/bozaro/go-work-play/tree/go-mod-tidy

Full script:

$ git clone https://github.com/bozaro/go-work-play.git -b go-mod-tidy
$ cd go-work-play/tools
$ go mod tidy
go: finding module for package github.com/bozaro/go/go-work-play/shared/foo
github.com/bozaro/go/go-work-play/tools/hello imports
	github.com/bozaro/go/go-work-play/shared/foo: module github.com/bozaro/go@latest found (v0.0.0-20200925035954-2333c6299f34), but does not contain package github.com/bozaro/go/go-work-play/shared/foo

What did you expect to see?

I expect go.mod and go.sum updated with current working copy state.

What did you see instead?

I see that go mod tidy try to get modules for shared go modules from repository ignoring go.work content.

[bcmills]

Tidiness is a property of an individual module, not a workspace: if a module is tidy, then a downstream consumer of the module knows which versions to use for every dependency of every package in that module.

If you don't particularly care about downstream consumers having a package that is provided by the workspace, you can use go mod tidy -e to ignore the error from the missing package.

Otherwise, you either need to publish the workspace dependencies before running go mod tidy (so that they have well-defined upstream versions), or tell the go command what those versions will be (using a replace and require directive in the individual module).

[bcmills]

@matloob, for Go 1.19 I wonder if we should augment the go.work file to be able to declare explicit intended versions for the modules in the workspace. Then go mod tidy could use those versions instead of looking upstream. 🤔

[bozaro]

Currently with reproducing repository (https://github.com/bozaro/go-work-play/tree/go-mod-tidy).

I can run:

cd tools/hello
go run .

And go run works like workspace go modules declared as replace in current tools/go.mod.

But for go mod tidy I need add replace manually.

This behaviour looks like inconsistent: I expects that go run and go mod tidy would use same dependencies.

[liadmord]

What valid use cases are there for go.work if we are still required to fully implement the go.mod in order to work on multi module repo?
@bcmills

[AlmogBaku]

This is also happening for go get ./...

I agree with @liadmord, the only benefit I see get from the go.work is a better "understanding" of my IDE
Or - maybe I'm doing something wrong here?

[Jictyvoo]

I agree with @bozaro @liadmord and @AlmogBaku

I have a monorepo private project where I have multiple modules, and on each one I need to insert a lot of replace statements for each direct and indirect dependencies. With go workspaces I really want to be possible to run go mod download or go mod tidy without the needed to write a replace statement in every go.mod file in my workspace.

[springeye]

Many of my colleagues have this need