fix: return error if more than one detected runtime

src/services/project/project.go

@@ -56,15 +56,24 @@ func New(name string, language string, directory string, runtimeVersion string,
 }
 
 func (proj *Project) detectType() (ProjectType, error) {
+	detectedRuntimes := 0
+	var projectType ProjectType
+	var err error
 	if _, err := os.Stat(path.Join(proj.Directory, "package.json")); err == nil {
 		proj.DefaultRuntimeVersion = defaults.DefaultNodeRuntimeVersion
-		return NodeProject, nil
+		detectedRuntimes++
+		projectType = NodeProject
 	} else if _, err := os.Stat(path.Join(proj.Directory, "go.mod")); err == nil {
 		proj.DefaultRuntimeVersion = defaults.DefaultGoRuntimeVersion
-		return GoProject, nil
+		detectedRuntimes++
+		projectType = GoProject
 	} else {
 		return "", fmt.Errorf("cannot detect project type %v", err)
 	}
+	if detectedRuntimes > 1 {
+		return "", fmt.Errorf("more than one project runtime detected, use --project-language flag or the INITIUM_PROJECT_LANGUAGE env variable to set the desired runtime")
+	}
+	return projectType, err
 }
 
 func (proj *Project) matchType() (ProjectType, error) {