modules and build tags

[Peter Waller]

Hi,

(I'm running master as of a few hours ago, devel +e5b1340 Wed Jul 25 23:53:54 2018 +0000 linux/amd64)

The following ("importing gonum.org/v1/gonum/stat/distmv and syncing") does not work, and I might expect it to:

$ mkdir tmp && cd tmp

$ go mod -init -module foo.to/tmp

go: creating new go.mod: module foo.to/tmp

$ echo $'package tmp\nimport "gonum.org/v1/gonum/stat/distmv"' > tmp.go

$ go mod -sync

go: finding gonum.org/v1/gonum/stat/distmv latest

go: finding gonum.org/v1/gonum/stat latest

go: finding gonum.org/v1/gonum latest

go: import "foo.to/tmp" ->

import "gonum.org/v1/gonum/stat/distmv": cannot find module providing package gonum.org/v1/gonum/stat/distmv

I reported this on gonum, and there is some discussion there: https://github.com/gonum/gonum/issues/454#issuecomment-408017101

I don't know how to proceed. Is the problem a module import cycle, or is it to do with build tags? Is it in Go, or gonum? I don't have time to dig in to this at the moment.

* Should I file an issue with Go, if so, what is the title? 

* Is there an easy workaround to make this work right now?

Thanks,

- Peter

[Bryan C. Mills]

On Thu, Jul 26, 2018 at 8:29 AM Peter Waller <pe...@pdftables.com> wrote:

Hi,

(I'm running master as of a few hours ago, devel +e5b1340 Wed Jul 25 23:53:54 2018 +0000 linux/amd64)

The following ("importing gonum.org/v1/gonum/stat/distmv and syncing") does not work, and I might expect it to:

$ mkdir tmp && cd tmp

$ go mod -init -module foo.to/tmp

go: creating new go.mod: module foo.to/tmp

$ echo $'package tmp\nimport "gonum.org/v1/gonum/stat/distmv"' > tmp.go

$ go mod -sync

go: finding gonum.org/v1/gonum/stat/distmv latest

go: finding gonum.org/v1/gonum/stat latest

go: finding gonum.org/v1/gonum latest

go: import "foo.to/tmp" ->

import "gonum.org/v1/gonum/stat/distmv": cannot find module providing package gonum.org/v1/gonum/stat/distmv

I reported this on gonum, and there is some discussion there: https://github.com/gonum/gonum/issues/454#issuecomment-408017101

I don't know how to proceed. Is the problem a module import cycle, or is it to do with build tags? Is it in Go, or gonum? I don't have time to dig in to this at the moment.

Cyclic imports are explicitly ok.

https://golang.org/issue/26602 has a similar symptom (“cannot find module” for a subpackage). I don't know whether the underlying cause is the same.

* Should I file an issue with Go, if so, what is the title?

Sure! “cmd/go: cannot find module for gonum.org/v1/gonum/stat/distmv” would be a good start.

 

* Is there an easy workaround to make this work right now?

None that I'm aware of.

[Peter Waller]

On Thu, 26 Jul 2018 at 22:46, Bryan C. Mills <bcm...@google.com> wrote:

* Should I file an issue with Go, if so, what is the title?

Sure! “cmd/go: cannot find module for gonum.org/v1/gonum/stat/distmv” would be a good start.

Filed: http://golang.org/issues/26632