reporegistry: add NoReposLoadedError and use it

pkg/reporegistry/error.go

@@ -0,0 +1,13 @@
+package reporegistry
+
+import "fmt"
+
+// NoReposLoadedError is an error type that is returned when no repositories
+// are loaded from the given paths.
+type NoReposLoadedError struct {
+	Paths []string
+}
+
+func (e *NoReposLoadedError) Error() string {
+	return fmt.Sprintf("no repositories found in the given paths: %v", e.Paths)
+}

pkg/reporegistry/reporegistry.go

@@ -23,9 +23,6 @@ func New(repoConfigPaths []string) (*RepoRegistry, error) {
 	if err != nil {
 		return nil, err
 	}
-	if len(repositories) == 0 {
-		return nil, fmt.Errorf("no repositories found in the given paths: %v", repoConfigPaths)
-	}
 
 	return &RepoRegistry{repositories}, nil
 }

pkg/reporegistry/repository.go

@@ -1,7 +1,6 @@
 package reporegistry
 
 import (
-	"fmt"
 	"log"
 	"os"
 	"path/filepath"
@@ -66,6 +65,10 @@ func LoadAllRepositories(confPaths []string) (rpmmd.DistrosRepoConfigs, error) {
 		}
 	}
 
+	if len(distrosRepoConfigs) == 0 {
+		return nil, &NoReposLoadedError{confPaths}
+	}
+
 	return distrosRepoConfigs, nil
 }
 
@@ -93,7 +96,7 @@ func LoadRepositories(confPaths []string, distro string) (map[string][]rpmmd.Rep
 	}
 
 	if repoConfigs == nil {
-		return nil, fmt.Errorf("LoadRepositories failed: none of the provided paths contain distro configuration")
+		return nil, &NoReposLoadedError{confPaths}
 	}
 
 	return repoConfigs, nil