stdout '"Ref": "HEAD"'
stdout '"Hash": "fc3a09f3dc5cfe0d7a743ea18f1f5226e68b3777"'
! stdout 'RepoSum'

# go mod download vcstest/hello@nonexist should fail, still print origin info
! go mod download -x -json vcs-test.golang.org/git/hello.git@nonexist
cp stdout hellononexist.json
stdout '"Version": "nonexist"'
stdout '"Error":.*unknown revision nonexist'
stdout '"RepoSum": "r1:c0/9JCZ25lxoBiK3[+]3BhACU4giH49flcJmBynJ[+]Jvmc="'

		tags, err := r.Tags(ctx, old.TagPrefix)
		if err != nil {
			return err
		}
		if tags.Origin.TagSum != old.TagSum {
			return fmt.Errorf("tags changed")
		}
	}
	if old.RepoSum != "" {
		if r.repoSum(r.refs) != old.RepoSum {
			return fmt.Errorf("refs changed")
		}
	}
	return nil
}

// loadRefs loads heads and tags references from the remote into the map r.refs.
// The result is cached in memory.

	Ref string `json:",omitempty"`

	// If RepoSum is non-empty, then the resolution of this module version
	// failed due to the repo being available but the version not being present.
	// This depends on the entire state of the repo, which RepoSum summarizes.
	// For Git, this is a hash of all the refs and their hashes.
	RepoSum string `json:",omitempty"`
}

	// If we got the previous Origin data from a proxy, it may be missing something
	// that we would have needed to resolve the query directly from the repo.
	switch {
	case origin.RepoSum != "":
		// A RepoSum is always acceptable, since it incorporates everything
		// (and is often associated with an error result).

	case query == module.CanonicalVersion(query):