With the introduction of the go.mod file and declaration of github.com/gofrs/uuid/v3 there is no longer a single import path that works correctly for both modules and non-modules users.

This has become an issue with gobuffalo/pop and other Buffalo projects.

Below you find a selection of go get statements that represent the different import paths and what happens when trying to use them in different environments.

Go >1.9.7 (or GO111MODULE=off)

$ go get github.com/gofrs/uuid/v3

package github.com/gofrs/uuid/v3: cannot find package "github.com/gofrs/uuid/v3" in any of:
    /usr/local/go/src/github.com/gofrs/uuid/v3 (from $GOROOT)
    /go/src/github.com/gofrs/uuid/v3 (from $GOPATH)

Go 1.11 (GO111MODULE=on)

$ go get github.com/gofrs/uuid

module github.com/gobuffalo/uuidmods

require github.com/gofrs/uuid v3.1.0+incompatible // indirect

$ go get github.com/gofrs/uuid/v3

module github.com/gobuffalo/uuidmods

require (
	github.com/gofrs/uuid/v3 v3.1.2 // indirect
)