Using local dependencies with Go modules

Go 1.16, released this week, deprecated GOPATH. I used it extensively to develop my libs before publishing them, but now I’m forced to convert them to modules, which work with remote repos by default. However, there’s a way to work with local dependencies.

As I found here, we can instruct Go toolchain to search for a local repo, instead of a remote one by using this command:

go mod edit -replace github.com/username/repo=../repo

This changes the go.mod file. Now, to clean up the go.sum file, run:

go mod tidy

After that, you should be able to use a local dependency just like the old GOPATH days.

The downloaded files are still cached, though. To finally clean the entire cache, run:

go clean -cache -modcache

Modules eventually needed by other applications will be downloaded again when due.