cmd/go: 1.18 fails when vendoring and main module replaces itself

[zhsj]

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

$ go version
go version go1.18rc1 linux/amd64

Does this issue reproduce with the latest release?

Yes

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/zhsj/.cache/go-build"
GOENV="/home/zhsj/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/zhsj/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/zhsj/go"
GOPRIVATE=""
GOPROXY="https://goproxy.cn"
GOROOT="/usr/lib/go-1.18"
GOSUMDB="sum.golang.google.cn"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.18/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18rc1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/zhsj/go/src/github.com/containerd/containerd/go.mod"
GOWORK=""
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-build2918392435=/tmp/go-build -gno-record-gcc-switches"

What did you do?

1. git clone https://github.com/containerd/containerd
2. run go list in root dir

What did you expect to see?

Like go1.17, it succeeds with:

zhsj@debian:~/go/src/github.com/containerd/containerd$ /usr/lib/go-1.17/bin/go list
github.com/containerd/containerd

What did you see instead?

zhsj@debian:~/go/src/github.com/containerd/containerd$ go list
go: inconsistent vendoring in /home/zhsj/go/src/github.com/containerd/containerd:
        github.com/containerd/containerd: is marked as replaced in vendor/modules.txt, but not replaced in go.mod

        To ignore the vendor directory, use -mod=readonly or -mod=mod.
        To sync the vendor directory, run:
                go mod vendor

[seankhliao]

related #34417

simpler reproducer:

-- go.mod --
module go.seankhliao.com/testrepo-791

go 1.18

replace go.seankhliao.com/testrepo-791 => ./.empty

-- .empty/go.mod
module go.seankhliao.com/testrepo-791

go 1.18

results:

$ go list
no Go files in /home/arccy/tmp/testrepo-791

$ go mod vendor
go: warning: "all" matched no packages

$ go list      
go: inconsistent vendoring in /home/arccy/tmp/testrepo-791:
	go.seankhliao.com/testrepo-791: is marked as replaced in vendor/modules.txt, but not replaced in go.mod

	To ignore the vendor directory, use -mod=readonly or -mod=mod.
	To sync the vendor directory, run:
		go mod vendor

cc @bcmills @matloob

[bcmills]

Duplicate of #34417

[bcmills]

Looking at the specific example of github.com/containerd/containerd, I see (https://github.com/containerd/containerd/blob/main/go.mod#L90-L91):

	// prevent transitional dependencies due to containerd having a circular
	// dependency on itself through plugins. see .empty-mod/go.mod for details

As of Go 1.17, the appropriate way to prune out cyclic dependencies is to update the go directive in the main module and any problematic dependencies to go 1.17 or higher to activate module graph pruning.

For compatibility with older go versions, you could pair that with exclude directives for specific older versions of the main module that you want to prune out.