dont suppress all exceptions, ask if method exists first

fix spec: we actually did not test if Fixnum did not respond since we never undefined the methods
add additional case to handle being provided a nil value

Author: mach-kernel

lib/api-pagination.rb

@@ -68,24 +68,23 @@ def paginate_with_will_paginate(collection, options)
 
     def get_default_per_page_for_kaminari(collection)
       default = Kaminari.config.default_per_page
-      detect_model(collection).default_per_page || default
-    rescue
-      default
+      extract_per_page_from_model(collection, :default_per_page) || default
     end
 
     def default_per_page_for_will_paginate(collection)
       default = WillPaginate.per_page
-      detect_model(collection).per_page || default
-    rescue
-      default
+      extract_per_page_from_model(collection, :per_page) || default
     end
 
-    def detect_model(collection)
-      if collection.respond_to?(:klass)
+    def extract_per_page_from_model(collection, accessor)
+      klass = if collection.respond_to?(:klass)
         collection.klass
       else
         collection.first.class
       end
+
+      return unless klass.respond_to?(accessor)
+      klass.send(accessor)
     end
   end
 end

spec/rails_spec.rb

@@ -287,7 +287,7 @@ class Fixnum
         expect(response.header['Per-Page']).to eq('6')
       end
 
-      it 'should not fail if model does not respond to per page' do
+      it 'should not fail if the model yields nil for per page' do
         class Fixnum
           @default_per_page = nil
           @per_page = nil
@@ -302,6 +302,26 @@ class Fixnum
           end
         )
       end
+
+      # This spec has to be last because if we undefine these methods
+      # at runtime and then invoke another test that uses them, they will
+      # raise a NoMethodError
+      it 'should not fail if model does not respond to per page' do
+        class Fixnum
+          class << self
+            undef_method :default_per_page, :per_page
+          end
+        end
+
+        get :index_with_no_per_page, params: {count: 100}
+
+        expect(response.header['Per-Page']).to eq(
+          case ApiPagination.config.paginator
+          when :kaminari      then Kaminari.config.default_per_page.to_s
+          when :will_paginate then WillPaginate.per_page.to_s
+          end
+        )
+      end
     end
   end
 end