Go modules replaces an explicit version with v0.0.0-<timestamp>-<revision> in go.mod

Question

I recently added a feature to my Go project which might break other projects that uses it. I decided to bump a major version to this project, "A", by adding a matching git tag 2.0.0 (it was previously 1.xx ). In my other project which requires it, "B", I updated its go.mod file like so:

module gitlab.mydomain.com/namespace/B

go 1.12

require (
    gitlab.mydomain.com/namespace/A v2.0.0
)

As you can see, I specifically mentioned v2.0.0 , but once I run B, the version of A is being overridden with v0.0.0-<timestamp>-<revision> .

I made sure that the tag exists in the remote.

What am I missing here?

Answer 1

Starting with major version 2 ( v2 and beyond), you have to modify the import path, you have to add the major version as a suffix to the import path. You must import the package as:

import "gitlab.mydomain.com/namespace/A/v2"

And this must also appear in go.mod like:

require gitlab.mydomain.com/namespace/A/v2 v2.0.0

Since major versions represent incompatible changes in Semver, their import path must also differ (the same import path denotes the same dependency). This is the import compatibility rule :

If an old package and a new package have the same import path,
the new package must be backwards compatible with the old package.

Read more about it in Go Modules Wiki: Why must major version numbers appear in import paths?

And also in blog post: The Go Blog: Go Modules: v2 and Beyond