How to Test Local Changes with Go Mod

We are developing on two different Go projects using modules:

• A github.com/acme/bar module

• Another github.com/acme/foo module that depends on the first one

Let’s say we made some changes to github.com/acme/bar and we would like to test the impacts on github.com/acme/foo before committing them.

Without Go modules, it was pretty straightforward as our changes were done in GOPATH so they were automatically reflected.

With Go modules, the trick is to replace our import by the physical location of the project:

module github.com/acme/foo

go 1.12

require (
    github.com/acme/bar v1.0.0
)

replace github.com/acme/bar => /path/to/local/bar

Here, /path/to/local/bar is the actual location of the bar project containing the local changes.

We can also use the following command:

go mod edit -replace github.com/acme/bar=/path/to/local/bar