cmd/go: go list -m -json GoMod field is not populated sometimes

[hyangah]

go version: 1.16rc1

I ran the go list command back to back, and noticed the GoMod field was not populated during the very first try.

$ GOPROXY=direct GOSUMDB=off GOPATH=/tmp/x /Users/hakim/sdk/go1.16rc1/bin/go  list -m -json --versions github.com/hyangah/retracttest/a@latest
{
        "Path": "github.com/hyangah/retracttest/a",
        "Version": "v0.0.0-20201117044135-c0d2dc84e45f",
        "Time": "2020-11-17T04:41:35Z",
        "GoVersion": "1.15"
}
$ GOPROXY=direct GOSUMDB=off GOPATH=/tmp/x /Users/hakim/sdk/go1.16rc1/bin/go  list -m -json --versions github.com/hyangah/retracttest/a@latest
{
        "Path": "github.com/hyangah/retracttest/a",
        "Version": "v0.0.0-20201117044135-c0d2dc84e45f",
        "Time": "2020-11-17T04:41:35Z",
        "GoMod": "/tmp/x/pkg/mod/cache/download/github.com/hyangah/retracttest/a/@v/v0.0.0-20201117044135-c0d2dc84e45f.mod",
        "GoVersion": "1.15"
}

[iwdgo]

Issue still occurs on go1.16.3. The first go list command loads the cache reported by GoMod as in the second use of the command. Manually deleting the folder reported by GoMod repeats the behavior.

On tip, issue seems solved probably because of CL 293689 which updates #40775 by refactoring modload.LoadFile(ctx)

It seems that issue can be closed for now.

[ianlancetaylor]

This is in the Go1.18 milestone. Is it likely to happen for 1.18? Thanks.

[ianlancetaylor]

@bcmills This is in the 1.18 milestone; time to move to 1.19? Thanks.

[bcmills]

On tip, issue seems solved probably because of CL 293689 which updates #40775 by refactoring modload.LoadFile(ctx)

It seems that issue can be closed for now.

Closing on the theory that this may have been fixed by changes in modload/list.go and/or cmd/go/internal/list/list.go (there have been substantial changes in both since 1.16rc1).

Please reopen (or open a new issue) if you observe this in Go 1.18beta2 or higher.