diff --git a/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache b/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache
index f6ebfff3791..a109dd19f0a 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache
@@ -14,7 +14,9 @@
       super(attributes)
       {{/parent}}
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -22,8 +24,6 @@
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb
index 907b30a85ed..c7cac8e7b51 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb
@@ -115,7 +115,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -123,8 +125,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb
index f0e70723770..35e4003eabb 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb
@@ -123,7 +123,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -131,8 +133,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb
index 4e0353a7c0f..d1436c37aa2 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb
@@ -120,7 +120,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -128,8 +130,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb
index b7436abad64..ce0cc55df8c 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb
index 49e40ea4d2a..828b37c49e9 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb
index 4d0b7ccbe6a..761a112a686 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb
@@ -126,7 +126,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -134,8 +136,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb
index c3e42cc3459..351832d8e2a 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb
@@ -148,7 +148,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -156,8 +158,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb
index 7561974beca..f39578b7a81 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb
@@ -114,7 +114,9 @@ module Petstore
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -122,8 +124,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/cat_all_of.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/cat_all_of.rb
index 85d785dcb85..d2bc0e45226 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/cat_all_of.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/cat_all_of.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb
index 7fea27bb012..8849bbd0a8f 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb
@@ -118,7 +118,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -126,8 +128,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb
index ec4ebfec166..0f99e929fd3 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb
@@ -103,7 +103,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -111,8 +113,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb
index d399fd79800..9e3132fb8ff 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb
index 1a934fe57e8..8fe034e9b04 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb
@@ -114,7 +114,9 @@ module Petstore
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -122,8 +124,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/dog_all_of.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/dog_all_of.rb
index 50ee42f907c..cfdd96a6730 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/dog_all_of.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/dog_all_of.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb
index a7574eb550d..390882b0dbb 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb
@@ -147,7 +147,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -155,8 +157,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb
index 5388a242a19..879b2519373 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb
@@ -245,7 +245,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -253,8 +255,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb
index 748022245bc..4484ded785e 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb
index a417d92f2f2..53e6fa92c7e 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb
@@ -113,7 +113,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -121,8 +123,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb
index bd586869942..aa89cdb86c8 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/foo.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb
index beb1cdf45f0..72f984ad5d9 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb
@@ -453,7 +453,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -461,8 +463,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb
index e852e347484..cffea3c4f2b 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb
@@ -111,7 +111,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -119,8 +121,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb
index f1c211ba33f..40edcf4051b 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/health_check_result.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object.rb
index c21518bef1b..a536777904c 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object.rb
@@ -113,7 +113,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -121,8 +123,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object1.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object1.rb
index d1260093ec4..18e98c4dfa3 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object1.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object1.rb
@@ -113,7 +113,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -121,8 +123,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object2.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object2.rb
index ef0b9d20eb6..ec2c742f019 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object2.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object2.rb
@@ -151,7 +151,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -159,8 +161,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object3.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object3.rb
index 5a3cbb63885..6375a99b542 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object3.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object3.rb
@@ -434,7 +434,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -442,8 +444,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object4.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object4.rb
index 9dac16c49c8..097c14a4b26 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object4.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object4.rb
@@ -123,7 +123,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -131,8 +133,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object5.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object5.rb
index 87c6d4c7fcf..526a3c198cc 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object5.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_object5.rb
@@ -118,7 +118,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -126,8 +128,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_response_default.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_response_default.rb
index a451606ee78..f1f159233ad 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_response_default.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/inline_response_default.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb
index 77df8f391eb..c4877244e9b 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb
index 1d5c6875cbd..a65b7eb381a 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb
@@ -159,7 +159,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -167,8 +169,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
index 74e20a06346..7ec29d7d2e9 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
@@ -122,7 +122,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -130,8 +132,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb
index ce843f3e564..be8cf95fc31 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb
@@ -112,7 +112,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -120,8 +122,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb
index b0894f91daa..f6a41e40131 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb
@@ -103,7 +103,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -111,8 +113,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb
index 937a87d9a40..735b9071b58 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb
@@ -135,7 +135,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -143,8 +145,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb
index 2250145bba4..147351a7409 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/nullable_class.rb
@@ -223,7 +223,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -231,8 +233,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb
index 337d7bd43bc..2a853e03d69 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb
index bb9c7b4fa15..fc9b6e686f1 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb
@@ -184,7 +184,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -192,8 +194,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb
index cacbd257555..725f33005c2 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb
@@ -120,7 +120,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -128,8 +130,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb
index ae61ebf6feb..f70ae5b6699 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb
@@ -196,7 +196,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -204,8 +206,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb
index 2e3b1e8ac52..63ec657b459 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb
@@ -111,7 +111,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -119,8 +121,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb
index 27ff34c4be8..b0b95a12ca8 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb
index f67fcd1399b..9b3ae91db46 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb
@@ -111,7 +111,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -119,8 +121,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb b/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb
index 2a6abc392a0..86dfb3f52ec 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb
@@ -166,7 +166,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -174,8 +176,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb b/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb
index 907b30a85ed..c7cac8e7b51 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb
@@ -115,7 +115,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -123,8 +125,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/animal.rb b/samples/client/petstore/ruby/lib/petstore/models/animal.rb
index f0e70723770..35e4003eabb 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/animal.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/animal.rb
@@ -123,7 +123,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -131,8 +133,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/api_response.rb b/samples/client/petstore/ruby/lib/petstore/models/api_response.rb
index 4e0353a7c0f..d1436c37aa2 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/api_response.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/api_response.rb
@@ -120,7 +120,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -128,8 +130,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb b/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb
index b7436abad64..ce0cc55df8c 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb b/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb
index 49e40ea4d2a..828b37c49e9 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/array_test.rb b/samples/client/petstore/ruby/lib/petstore/models/array_test.rb
index 4d0b7ccbe6a..761a112a686 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/array_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/array_test.rb
@@ -126,7 +126,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -134,8 +136,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb b/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb
index c3e42cc3459..351832d8e2a 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/capitalization.rb
@@ -148,7 +148,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -156,8 +158,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/cat.rb b/samples/client/petstore/ruby/lib/petstore/models/cat.rb
index 7561974beca..f39578b7a81 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/cat.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/cat.rb
@@ -114,7 +114,9 @@ module Petstore
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -122,8 +124,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/cat_all_of.rb b/samples/client/petstore/ruby/lib/petstore/models/cat_all_of.rb
index 85d785dcb85..d2bc0e45226 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/cat_all_of.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/cat_all_of.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/category.rb b/samples/client/petstore/ruby/lib/petstore/models/category.rb
index 7fea27bb012..8849bbd0a8f 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/category.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/category.rb
@@ -118,7 +118,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -126,8 +128,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/class_model.rb b/samples/client/petstore/ruby/lib/petstore/models/class_model.rb
index ec4ebfec166..0f99e929fd3 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/class_model.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/class_model.rb
@@ -103,7 +103,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -111,8 +113,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/client.rb b/samples/client/petstore/ruby/lib/petstore/models/client.rb
index d399fd79800..9e3132fb8ff 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/client.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/client.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/dog.rb b/samples/client/petstore/ruby/lib/petstore/models/dog.rb
index 1a934fe57e8..8fe034e9b04 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/dog.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/dog.rb
@@ -114,7 +114,9 @@ module Petstore
       return nil unless attributes.is_a?(Hash)
       super(attributes)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -122,8 +124,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/dog_all_of.rb b/samples/client/petstore/ruby/lib/petstore/models/dog_all_of.rb
index 50ee42f907c..cfdd96a6730 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/dog_all_of.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/dog_all_of.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb b/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb
index a7574eb550d..390882b0dbb 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb
@@ -147,7 +147,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -155,8 +157,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb b/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb
index 5388a242a19..879b2519373 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/enum_test.rb
@@ -245,7 +245,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -253,8 +255,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/file.rb b/samples/client/petstore/ruby/lib/petstore/models/file.rb
index 748022245bc..4484ded785e 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/file.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/file.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb b/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb
index a417d92f2f2..53e6fa92c7e 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb
@@ -113,7 +113,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -121,8 +123,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/foo.rb b/samples/client/petstore/ruby/lib/petstore/models/foo.rb
index bd586869942..aa89cdb86c8 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/foo.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/foo.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/format_test.rb b/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
index beb1cdf45f0..72f984ad5d9 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/format_test.rb
@@ -453,7 +453,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -461,8 +463,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb b/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb
index e852e347484..cffea3c4f2b 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb
@@ -111,7 +111,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -119,8 +121,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb b/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb
index f1c211ba33f..40edcf4051b 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/health_check_result.rb
@@ -104,7 +104,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -112,8 +114,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/inline_object.rb b/samples/client/petstore/ruby/lib/petstore/models/inline_object.rb
index c21518bef1b..a536777904c 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/inline_object.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/inline_object.rb
@@ -113,7 +113,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -121,8 +123,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/inline_object1.rb b/samples/client/petstore/ruby/lib/petstore/models/inline_object1.rb
index d1260093ec4..18e98c4dfa3 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/inline_object1.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/inline_object1.rb
@@ -113,7 +113,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -121,8 +123,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/inline_object2.rb b/samples/client/petstore/ruby/lib/petstore/models/inline_object2.rb
index ef0b9d20eb6..ec2c742f019 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/inline_object2.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/inline_object2.rb
@@ -151,7 +151,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -159,8 +161,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/inline_object3.rb b/samples/client/petstore/ruby/lib/petstore/models/inline_object3.rb
index 5a3cbb63885..6375a99b542 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/inline_object3.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/inline_object3.rb
@@ -434,7 +434,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -442,8 +444,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/inline_object4.rb b/samples/client/petstore/ruby/lib/petstore/models/inline_object4.rb
index 9dac16c49c8..097c14a4b26 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/inline_object4.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/inline_object4.rb
@@ -123,7 +123,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -131,8 +133,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/inline_object5.rb b/samples/client/petstore/ruby/lib/petstore/models/inline_object5.rb
index 87c6d4c7fcf..526a3c198cc 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/inline_object5.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/inline_object5.rb
@@ -118,7 +118,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -126,8 +128,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/inline_response_default.rb b/samples/client/petstore/ruby/lib/petstore/models/inline_response_default.rb
index a451606ee78..f1f159233ad 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/inline_response_default.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/inline_response_default.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/list.rb b/samples/client/petstore/ruby/lib/petstore/models/list.rb
index 77df8f391eb..c4877244e9b 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/list.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/list.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/map_test.rb b/samples/client/petstore/ruby/lib/petstore/models/map_test.rb
index 1d5c6875cbd..a65b7eb381a 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/map_test.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/map_test.rb
@@ -159,7 +159,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -167,8 +169,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb b/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
index 74e20a06346..7ec29d7d2e9 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb
@@ -122,7 +122,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -130,8 +132,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb b/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb
index ce843f3e564..be8cf95fc31 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/model200_response.rb
@@ -112,7 +112,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -120,8 +122,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/model_return.rb b/samples/client/petstore/ruby/lib/petstore/models/model_return.rb
index b0894f91daa..f6a41e40131 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/model_return.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/model_return.rb
@@ -103,7 +103,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -111,8 +113,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/name.rb b/samples/client/petstore/ruby/lib/petstore/models/name.rb
index 937a87d9a40..735b9071b58 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/name.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/name.rb
@@ -135,7 +135,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -143,8 +145,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb b/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb
index 2250145bba4..147351a7409 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/nullable_class.rb
@@ -223,7 +223,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -231,8 +233,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/number_only.rb b/samples/client/petstore/ruby/lib/petstore/models/number_only.rb
index 337d7bd43bc..2a853e03d69 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/number_only.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/number_only.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/order.rb b/samples/client/petstore/ruby/lib/petstore/models/order.rb
index bb9c7b4fa15..fc9b6e686f1 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/order.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/order.rb
@@ -184,7 +184,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -192,8 +194,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb b/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb
index cacbd257555..725f33005c2 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb
@@ -120,7 +120,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -128,8 +130,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/pet.rb b/samples/client/petstore/ruby/lib/petstore/models/pet.rb
index ae61ebf6feb..f70ae5b6699 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/pet.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/pet.rb
@@ -196,7 +196,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -204,8 +206,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb b/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb
index 2e3b1e8ac52..63ec657b459 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb
@@ -111,7 +111,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -119,8 +121,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb b/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb
index 27ff34c4be8..b0b95a12ca8 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb
@@ -102,7 +102,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -110,8 +112,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/tag.rb b/samples/client/petstore/ruby/lib/petstore/models/tag.rb
index f67fcd1399b..9b3ae91db46 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/tag.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/tag.rb
@@ -111,7 +111,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -119,8 +121,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end
 
diff --git a/samples/client/petstore/ruby/lib/petstore/models/user.rb b/samples/client/petstore/ruby/lib/petstore/models/user.rb
index 2a6abc392a0..86dfb3f52ec 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/user.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/user.rb
@@ -166,7 +166,9 @@ module Petstore
     def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       self.class.openapi_types.each_pair do |key, type|
-        if type =~ /\AArray<(.*)>/i
+        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
+          self.send("#{key}=", nil)
+        elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
           if attributes[self.class.attribute_map[key]].is_a?(Array)
@@ -174,8 +176,6 @@ module Petstore
           end
         elsif !attributes[self.class.attribute_map[key]].nil?
           self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
-        elsif attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
         end
       end