Go: require module from local folder with replace

I have:

• a module (/Users/collimarco/Sites/pushpad-go)
• a demo application that uses that module (/Users/collimarco/Sites/pushpad-example-app/go)

They are in two separate folders, in different paths.

I need to follow this structure, because the same convention is used for many other languages.

This is the module:

// /Users/collimarco/Sites/pushpad-go/go.mod

module github.com/pushpad/pushpad-go

go 1.19

This is the demo application that needs to use that module:

// /Users/collimarco/Sites/pushpad-example-app/go/go.mod

module pushpad-go-example

go 1.19

replace "github.com/pushpad/pushpad-go" v0.0.0 => "/Users/collimarco/Sites/pushpad-go"

// /Users/collimarco/Sites/pushpad-example-app/go/main.go

package main

import (
  "github.com/pushpad/pushpad-go/pushpad"
)

func main() {
  n := pushpad.Notification { Body: "Example notification" }
  n.Broadcast()
}

I read different blog posts and that seems the correct approach. However I get this error:

$ go run .
main.go:4:3: no required module provides package github.com/pushpad/pushpad-go/pushpad; to add it:
	go get github.com/pushpad/pushpad-go/pushpad

I don't want to download the module from an online repository, as the error suggests: I just want to import the code from the local folder. What should I do?

The first problem here is that you're importing github.com/pushpad/pushpad-go/pushpad; the trailing /pushpad is a problem because that is not part of the repository path. So the code in your main.go should have:

import (
  "github.com/pushpad/pushpad-go"
)

You still need a require directive for the module as well. If you go get it at version v0.0.0, the replace directive will retrieve it from your local folder. So:

go get github.com/pushpad/pushpad-go@0.0.0

should add this to your go.mod:

require (
    github.com/pushpad/pushpad-go v0.0.0
)

Also, quotes are not necessary in your replace directive. It should be:

replace github.com/pushpad/pushpad-go v0.0.0 => /Users/collimarco/Sites/pushpad-go

Another way of doing this, rather than editing your go.mod file manually, is to use go mod edit -replace like so:

go mod edit -replace github.com/pushpad/pushpad-go=/Users/collimarco/Sites/pushpad-go

That should "do the right thing".