Fix declared_hash_attr when passed_params is not an Hash

CHANGELOG.md

@@ -18,6 +18,7 @@
 * [#2546](https://github.com/ruby-grape/grape/pull/2546): Fix middleware with keywords - [@ericproulx](https://github.com/ericproulx).
 * [#2547](https://github.com/ruby-grape/grape/pull/2547): Remove jsonapi related code - [@ericproulx](https://github.com/ericproulx).
 * [#2548](https://github.com/ruby-grape/grape/pull/2548): Formatting from header acts like versioning from header - [@ericproulx](https://github.com/ericproulx).
+* [#2552](https://github.com/ruby-grape/grape/pull/2552): Fix declared params optional array - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 ### 2.3.0 (2025-02-08)

lib/grape/dsl/inside_route.rb

@@ -79,7 +79,7 @@ def declared_hash_attr(passed_params, options, declared_param, params_nested_pat
           else
             # If it is not a Hash then it does not have children.
             # Find its value or set it to nil.
-            return unless options[:include_missing] || passed_params.key?(declared_param)
+            return unless options[:include_missing] || passed_params.try(:key?, declared_param)
 
             rename_path = params_nested_path + [declared_param.to_s]
             renamed_param_name = renamed_params[rename_path]

spec/grape/endpoint/declared_spec.rb

@@ -856,4 +856,26 @@
       end
     end
   end
+
+  describe 'optional_array' do
+    subject { last_response }
+
+    let(:app) do
+      Class.new(Grape::API) do
+        params do
+          requires :z, type: Array do
+            optional :a, type: Integer
+          end
+        end
+
+        post do
+          declared(params, include_missing: false)
+        end
+      end
+    end
+
+    before { post '/', { z: [] } }
+
+    it { is_expected.to be_successful }
+  end
 end