Avoid array allocation in DSL::Parameters#with

CHANGELOG.md

@@ -12,6 +12,7 @@
 * [#2667](https://github.com/ruby-grape/grape/pull/2667): Skip instrumentation in run_validators when no validators present - [@ericproulx](https://github.com/ericproulx).
 * [#2670](https://github.com/ruby-grape/grape/pull/2670): Added support for Rack 3.2.6 and better handling to rack exceptions - [@ericproulx](https://github.com/ericproulx).
 * [#2671](https://github.com/ruby-grape/grape/pull/2671): Use ruby 3.1 shorthand kwargs syntax - [@ericproulx](https://github.com/ericproulx).
+* [#2672](https://github.com/ruby-grape/grape/pull/2672): Minor ruby optimizations - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 #### Fixes

lib/grape/dsl/parameters.rb

@@ -161,7 +161,7 @@ def optional(*attrs, **opts, &block)
       # @param (see #requires)
       # @option (see #requires)
       def with(**opts, &)
-        new_group_attrs = [@group, opts].compact.reduce(&:deep_merge)
+        new_group_attrs = @group&.deep_merge(opts) || opts
         new_group_scope(new_group_attrs, &)
       end
 

lib/grape/router.rb

@@ -76,6 +76,9 @@ def recognize_path(input)
       any.endpoint
     end
 
+    DEFAULT_RESPONSE_HEADERS = Grape::Util::Header.new.merge('X-Cascade' => 'pass').freeze
+    DEFAULT_RESPONSE_BODY = ['404 Not Found'].freeze
+
     private
 
     def identity(input, method, env)
@@ -146,8 +149,7 @@ def with_optimization
     end
 
     def default_response
-      headers = Grape::Util::Header.new.merge('X-Cascade' => 'pass')
-      [404, headers, ['404 Not Found']]
+      [404, DEFAULT_RESPONSE_HEADERS.dup, DEFAULT_RESPONSE_BODY.dup]
     end
 
     def match?(input, method)

lib/grape/util/inheritable_setting.rb

@@ -55,7 +55,7 @@ def inherit_from(parent)
         namespace_reverse_stackable.inherited_values = parent.namespace_reverse_stackable
         self.route = parent.route.merge(route)
 
-        point_in_time_copies.map { |cloned_one| cloned_one.inherit_from parent }
+        point_in_time_copies.each { |cloned_one| cloned_one.inherit_from parent }
       end
 
       # Create a point-in-time copy of this settings instance, with clones of