return error if gh client returns 404 to bubble up the workaround

cmd/clusterctl/client/repository/repository_github.go

@@ -49,6 +49,8 @@ const (
 )
 
 var (
+	errNotFound = errors.New("404 Not Found")
+
 	// Caches used to limit the number of GitHub API calls.
 
 	cacheVersions              = map[string][]string{}
@@ -226,7 +228,7 @@ func NewGitHubRepository(providerConfig config.Provider, configVariablesClient c
 	if defaultVersion == githubLatestReleaseLabel {
 		repo.defaultVersion, err = latestContractRelease(repo, clusterv1.GroupVersion.Version)
 		if err != nil {
-			return nil, errors.Wrap(err, "failed to get GitHub latest version")
+			return nil, errors.Wrap(err, "failed to get latest release")
 		}
 	}
 
@@ -332,6 +334,10 @@ func (g *gitHubRepository) getReleaseByTag(tag string) (*github.RepositoryReleas
 		release, _, getReleasesErr = client.Repositories.GetReleaseByTag(context.TODO(), g.owner, g.repository, tag)
 		if getReleasesErr != nil {
 			retryError = g.handleGithubErr(getReleasesErr, "failed to read release %q", tag)
+			// return immediately if not found
+			if errors.Is(retryError, errNotFound) {
+				return false, retryError
+			}
 			// return immediately if we are rate limited
 			if _, ok := getReleasesErr.(*github.RateLimitError); ok {
 				return false, retryError
@@ -418,5 +424,10 @@ func (g *gitHubRepository) handleGithubErr(err error, message string, args ...in
 	if _, ok := err.(*github.RateLimitError); ok {
 		return errors.New("rate limit for github api has been reached. Please wait one hour or get a personal API token and assign it to the GITHUB_TOKEN environment variable")
 	}
+	if ghErr, ok := err.(*github.ErrorResponse); ok {
+		if ghErr.Response.StatusCode == http.StatusNotFound {
+			return errNotFound
+		}
+	}
 	return errors.Wrapf(err, message, args...)
 }

cmd/clusterctl/client/repository/repository_versions.go

@@ -39,11 +39,16 @@ func latestContractRelease(repo Repository, contract string) (string, error) {
 	}
 	// Attempt to check if the latest release satisfies the API Contract
 	// This is a best-effort attempt to find the latest release for an older API contract if it's not the latest release.
-	// If an error occurs, we just return the latest release.
 	file, err := repo.GetFile(latest, metadataFile)
+	// If an error occurs, we just return the latest release.
 	if err != nil {
+		if errors.Is(err, errNotFound) {
+			// If it was ErrNotFound, then there is no release yet for the resolved tag.
+			// Ref: https://github.com/kubernetes-sigs/cluster-api/issues/7889
+			return "", errors.Wrap(err, "release does not exist yet, consider setting \"GOPROXY=off\" as workaround")
+		}
 		// if we can't get the metadata file from the release, we return latest.
-		return latest, nil //nolint:nilerr
+		return latest, nil
 	}
 	latestMetadata := &clusterctlv1.Metadata{}
 	codecFactory := serializer.NewCodecFactory(scheme.Scheme)