Avoid unnecessary add_setup calls (#926)

lib/grape-swagger.rb

@@ -24,7 +24,7 @@ module SwaggerRouting
   private
 
   def combine_routes(app, doc_klass)
-    app.routes.each do |route|
+    app.routes.each_with_object({}) do |route, combined_routes|
       route_path = route.path
       route_match = route_path.split(/^.*?#{route.prefix}/).last
       next unless route_match
@@ -37,31 +37,32 @@ def combine_routes(app, doc_klass)
 
       resource = route_match.captures.first
       resource = '/' if resource.empty?
-      @target_class.combined_routes[resource] ||= []
+      combined_routes[resource] ||= []
       next if doc_klass.hide_documentation_path && route.path.match(/#{doc_klass.mount_path}($|\/|\(\.)/)
 
-      @target_class.combined_routes[resource] << route
+      combined_routes[resource] << route
     end
   end
 
-  def determine_namespaced_routes(name, parent_route)
+  def determine_namespaced_routes(name, parent_route, routes)
     if parent_route.nil?
-      @target_class.combined_routes.values.flatten
+      routes.values.flatten
     else
       parent_route.reject do |route|
         !route_path_start_with?(route, name) || !route_instance_variable_equals?(route, name)
       end
     end
   end
 
-  def combine_namespace_routes(namespaces)
+  def combine_namespace_routes(namespaces, routes)
+    combined_namespace_routes = {}
     # iterate over each single namespace
     namespaces.each_key do |name, _|
       # get the parent route for the namespace
       parent_route_name = extract_parent_route(name)
-      parent_route = @target_class.combined_routes[parent_route_name]
+      parent_route = routes[parent_route_name]
       # fetch all routes that are within the current namespace
-      namespace_routes = determine_namespaced_routes(name, parent_route)
+      namespace_routes = determine_namespaced_routes(name, parent_route, routes)
 
       # default case when not explicitly specified or nested == true
       standalone_namespaces = namespaces.reject do |_, ns|
@@ -76,12 +77,13 @@ def combine_namespace_routes(namespaces)
       # rubocop:disable Style/Next
       if parent_standalone_namespaces.empty?
         # default option, append namespace methods to parent route
-        parent_route = @target_class.combined_namespace_routes.key?(parent_route_name)
-        @target_class.combined_namespace_routes[parent_route_name] = [] unless parent_route
-        @target_class.combined_namespace_routes[parent_route_name].push(*namespace_routes)
+        combined_namespace_routes[parent_route_name] ||= []
+        combined_namespace_routes[parent_route_name].push(*namespace_routes)
       end
       # rubocop:enable Style/Next
     end
+
+    combined_namespace_routes
   end
 
   def extract_parent_route(name)
@@ -110,7 +112,7 @@ def route_path_start_with?(route, name)
 end
 
 module SwaggerDocumentationAdder
-  attr_accessor :combined_namespaces, :combined_namespace_identifiers, :combined_routes, :combined_namespace_routes
+  attr_accessor :combined_namespaces, :combined_routes, :combined_namespace_routes
 
   include SwaggerRouting
 
@@ -127,20 +129,16 @@ def add_swagger_documentation(options = {})
     documentation_class.setup(options)
     mount(documentation_class)
 
-    @target_class.combined_routes = {}
-    combine_routes(@target_class, documentation_class)
-
-    @target_class.combined_namespaces = {}
-    combine_namespaces(@target_class)
+    combined_routes = combine_routes(@target_class, documentation_class)
+    combined_namespaces = combine_namespaces(@target_class)
+    combined_namespace_routes = combine_namespace_routes(combined_namespaces, combined_routes)
+    exclusive_route_keys = combined_routes.keys - combined_namespaces.keys
+    @target_class.combined_namespace_routes = combined_namespace_routes.merge(
+      combined_routes.slice(*exclusive_route_keys)
+    )
+    @target_class.combined_routes = combined_routes
+    @target_class.combined_namespaces = combined_namespaces
 
-    @target_class.combined_namespace_routes = {}
-    @target_class.combined_namespace_identifiers = {}
-    combine_namespace_routes(@target_class.combined_namespaces)
-
-    exclusive_route_keys = @target_class.combined_routes.keys - @target_class.combined_namespaces.keys
-    exclusive_route_keys.each do |key|
-      @target_class.combined_namespace_routes[key] = @target_class.combined_routes[key]
-    end
     documentation_class
   end
 
@@ -151,17 +149,24 @@ def version_for(options)
   end
 
   def combine_namespaces(app)
-    app.endpoints.each do |endpoint|
+    combined_namespaces = {}
+    endpoints = app.endpoints.clone
+
+    while endpoints.any?
+      endpoint = endpoints.shift
+
+      endpoints.push(*endpoint.options[:app].endpoints) if endpoint.options[:app]
       ns = endpoint.namespace_stackable(:namespace).last
+      next unless ns
 
       # use the full namespace here (not the latest level only)
       # and strip leading slash
       mount_path = (endpoint.namespace_stackable(:mount_path) || []).join('/')
       full_namespace = (mount_path + endpoint.namespace).sub(/\/{2,}/, '/').sub(/^\//, '')
-      @target_class.combined_namespaces[full_namespace] = ns if ns
-
-      combine_namespaces(endpoint.options[:app]) if endpoint.options[:app]
+      combined_namespaces[full_namespace] = ns
     end
+
+    combined_namespaces
   end
 
   def create_documentation_class