missing go.sum entry after ran go mod tidy

[jackieli-tes]

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Describe the bug

Following docs, after initial command wire, then after go mod tidy, subsequent go generate ./... reports:

/go/pkg/mod/github.com/google/wire@v0.5.0/cmd/wire/main.go:34:2: missing go.sum entry for module providing package github.com/google/subcommands (imported by github.com/google/wire/cmd/wire); to add:
        go get github.com/google/wire/cmd/wire@v0.5.0
/go/pkg/mod/github.com/google/wire@v0.5.0/cmd/wire/main.go:36:2: missing go.sum entry for module providing package github.com/pmezard/go-difflib/difflib (imported by github.com/google/wire/cmd/wire); to add:
        go get github.com/google/wire/cmd/wire@v0.5.0
/go/pkg/mod/github.com/google/wire@v0.5.0/internal/wire/copyast.go:21:2: missing go.sum entry for module providing package golang.org/x/tools/go/ast/astutil (imported by github.com/google/wire/internal/wire); to add:
        go get github.com/google/wire/internal/wire@v0.5.0
/go/pkg/mod/github.com/google/wire@v0.5.0/internal/wire/parse.go:30:2: missing go.sum entry for module providing package golang.org/x/tools/go/packages (imported by github.com/google/wire/internal/wire); to add:
        go get github.com/google/wire/internal/wire@v0.5.0
/go/pkg/mod/github.com/google/wire@v0.5.0/internal/wire/analyze.go:26:2: missing go.sum entry for module providing package golang.org/x/tools/go/types/typeutil (imported by github.com/google/wire/cmd/wire); to add:
        go get github.com/google/wire/cmd/wire@v0.5.0
wire_gen.go:3: running "go": exit status 1

To Reproduce

I use this command to reproduce the problem:

docker build - <<EOF
FROM golang
WORKDIR /myproject
RUN go mod init myproject

RUN echo '// +build wireinject' >> wire.go
RUN echo 'package main' >> wire.go
RUN echo 'import ("strings"; "github.com/google/wire")' >> wire.go
RUN echo 'func initReader(s string) *strings.Reader {' >> wire.go
RUN echo '	panic(wire.Build(strings.NewReader))' >> wire.go
RUN echo '}' >> wire.go

RUN go get github.com/google/wire/cmd/wire
RUN wire
RUN cat wire_gen.go
RUN go mod tidy
RUN cat go.mod
RUN go generate ./...
EOF

Expected behavior

go generate ./... should run without error

Version

go 1.16

github.com/google/wire v0.5.0

Additional context

Following the error message and run the suggest go get commands fixes the problem. But as soon as I run go mod tidy, go generate ./... reports error

[drscre]

Possibly related to golang/go#44129

As a hack, you can run GOFLAGS=-mod=mod go generate ./...

[jackieli-tes]

Possibly related to golang/go#44129

As a hack, you can run GOFLAGS=-mod=mod go generate ./...

I can confirm the workaround working

[drewolson]

FWIW, I think the "correct" work-around is to follow the advice here and create a tools.go file to track your development-only dependencies. This should resolve the go.sum problem and doesn't require setting GOFLAGS that introduce potentially unintuitive behavior.

[ccremer]

I have the same problem. I do have a tools.go file yet the go.sum entry is still missing after go mod tidy

// +build tools

// Place any runtime dependencies as imports in this file.
// Go modules will be forced to download and install them.
package tools

import (
	_ "github.com/google/wire"
)

(Go 1.16.7)

[drewolson]

// +build tools

// Place any runtime dependencies as imports in this file.
// Go modules will be forced to download and install them.
package tools

import (
	_ "github.com/google/wire"
)

(Go 1.16.7)

I believe this is because you need to be importing "github.com/google/wire/cmd/wire". This is the actual tool you use, not the library.

[ccremer]

you need to be importing "github.com/google/wire/cmd/wire".

Good catch!
This was the culprit, now it works.
Thanks a lot 🎉

[jackieli-tes]

Yes, I'm using the // +build tools workaround as well

There is some guidelines from here about tracking tools: https://github.com/golang/go/wiki/Modules#how-can-i-track-tool-dependencies-for-a-module

And in my case importing github.com/google/wire/cmd/wire is enough. Full tools.go:

// +build tools

// following https://github.com/golang/go/wiki/Modules#how-can-i-track-tool-dependencies-for-a-module

package main

import (
	_ "github.com/google/wire/cmd/wire"
)

[tx7do]

add import:

package tools

import (
	_ "github.com/google/subcommands"
)

then :

go mod tidy.

[manubu1012]

you can try go clean --modcache, then: go generate again