Ruby client nullable (#4391)

* Ruby Client: implementation of nullable

* Ruby samples with nullable implementation

* [Ruby] openapi_nullable as a Set and skipping attrs fix

modules/openapi-generator/src/main/resources/ruby-client/base_object.mustache

@@ -87,7 +87,11 @@
       hash = {{^parent}}{}{{/parent}}{{#parent}}super{{/parent}}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

modules/openapi-generator/src/main/resources/ruby-client/partial_model_generic.mustache

@@ -51,6 +51,17 @@
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+        {{#vars}}
+        {{#isNullable}}
+        :'{{{name}}}'{{#hasMore}},{{/hasMore}}
+        {{/isNullable}}
+        {{/vars}}
+      ])
+    end
+
     {{#anyOf}}
     {{#-first}}
     # List of class defined in anyOf (OpenAPI v3)

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_any_type.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_array.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_boolean.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb

@@ -70,6 +70,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -275,7 +281,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_integer.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_number.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_object.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_string.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/animal.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # discriminator's property name in OpenAPI v3
     def self.openapi_discriminator_name
       :'class_name'
@@ -190,7 +196,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -187,7 +193,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -193,7 +199,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb

@@ -51,6 +51,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -215,7 +221,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/cat.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # List of class defined in allOf (OpenAPI v3)
     def self.openapi_all_of
       [
@@ -181,7 +187,11 @@ module Petstore
       hash = super
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/cat_all_of.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/category.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -185,7 +191,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/class_model.rb

@@ -31,6 +31,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -170,7 +176,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/client.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/dog.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # List of class defined in allOf (OpenAPI v3)
     def self.openapi_all_of
       [
@@ -181,7 +187,11 @@ module Petstore
       hash = super
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/dog_all_of.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/enum_arrays.rb

@@ -56,6 +56,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -214,7 +220,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/enum_test.rb

@@ -68,6 +68,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -280,7 +286,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/file.rb

@@ -32,6 +32,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/file_schema_test_class.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -180,7 +186,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/format_test.rb

@@ -82,6 +82,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -496,7 +502,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/has_only_read_only.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -178,7 +184,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/list.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/map_test.rb

@@ -64,6 +64,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -226,7 +232,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/mixed_properties_and_additional_properties_class.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -189,7 +195,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/model200_response.rb

@@ -35,6 +35,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -179,7 +185,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/model_return.rb

@@ -31,6 +31,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -170,7 +176,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/name.rb

@@ -43,6 +43,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -202,7 +208,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/order.rb

@@ -73,6 +73,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -251,7 +257,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/outer_composite.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -187,7 +193,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/pet.rb

@@ -73,6 +73,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -263,7 +269,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/read_only_first.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -178,7 +184,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/special_model_name.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/tag.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -178,7 +184,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/type_holder_default.rb

@@ -46,6 +46,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -236,7 +242,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/type_holder_example.rb

@@ -50,6 +50,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -246,7 +252,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/user.rb

@@ -59,6 +59,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -233,7 +239,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby-faraday/lib/petstore/models/xml_item.rb

@@ -142,6 +142,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -439,7 +445,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_any_type.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_array.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_boolean.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_class.rb

@@ -70,6 +70,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -275,7 +281,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_integer.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_number.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_object.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/additional_properties_string.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/animal.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # discriminator's property name in OpenAPI v3
     def self.openapi_discriminator_name
       :'class_name'
@@ -190,7 +196,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/api_response.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -187,7 +193,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/array_of_array_of_number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/array_of_number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/array_test.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -193,7 +199,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/capitalization.rb

@@ -51,6 +51,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -215,7 +221,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/cat.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # List of class defined in allOf (OpenAPI v3)
     def self.openapi_all_of
       [
@@ -181,7 +187,11 @@ module Petstore
       hash = super
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/cat_all_of.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/category.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -185,7 +191,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/class_model.rb

@@ -31,6 +31,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -170,7 +176,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/client.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/dog.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # List of class defined in allOf (OpenAPI v3)
     def self.openapi_all_of
       [
@@ -181,7 +187,11 @@ module Petstore
       hash = super
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/dog_all_of.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/enum_arrays.rb

@@ -56,6 +56,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -214,7 +220,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/enum_test.rb

@@ -68,6 +68,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -280,7 +286,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/file.rb

@@ -32,6 +32,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/file_schema_test_class.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -180,7 +186,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/format_test.rb

@@ -82,6 +82,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -496,7 +502,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/has_only_read_only.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -178,7 +184,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/list.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/map_test.rb

@@ -64,6 +64,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -226,7 +232,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/mixed_properties_and_additional_properties_class.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -189,7 +195,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/model200_response.rb

@@ -35,6 +35,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -179,7 +185,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/model_return.rb

@@ -31,6 +31,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -170,7 +176,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/name.rb

@@ -43,6 +43,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -202,7 +208,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/order.rb

@@ -73,6 +73,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -251,7 +257,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/outer_composite.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -187,7 +193,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/pet.rb

@@ -73,6 +73,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -263,7 +269,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/read_only_first.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -178,7 +184,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/special_model_name.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/tag.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -178,7 +184,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/type_holder_default.rb

@@ -46,6 +46,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -236,7 +242,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/type_holder_example.rb

@@ -50,6 +50,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -246,7 +252,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/user.rb

@@ -59,6 +59,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -233,7 +239,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/client/petstore/ruby/lib/petstore/models/xml_item.rb

@@ -142,6 +142,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -439,7 +445,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/additional_properties_class.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -182,7 +188,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/animal.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # discriminator's property name in OpenAPI v3
     def self.openapi_discriminator_name
       :'class_name'
@@ -190,7 +196,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/api_response.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -187,7 +193,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/array_of_array_of_number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/array_of_number_only.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -171,7 +177,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/array_test.rb

@@ -38,6 +38,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -193,7 +199,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/capitalization.rb

@@ -51,6 +51,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -215,7 +221,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/cat.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # List of class defined in allOf (OpenAPI v3)
     def self.openapi_all_of
       [
@@ -181,7 +187,11 @@ module Petstore
       hash = super
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/cat_all_of.rb

@@ -30,6 +30,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -169,7 +175,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash

samples/openapi3/client/petstore/ruby-faraday/lib/petstore/models/category.rb

@@ -34,6 +34,12 @@ module Petstore
       }
     end
 
+    # List of attributes with nullable: true
+    def self.openapi_nullable
+      Set.new([
+      ])
+    end
+
     # Initializes the object
     # @param [Hash] attributes Model attributes in the form of hash
     def initialize(attributes = {})
@@ -185,7 +191,11 @@ module Petstore
       hash = {}
       self.class.attribute_map.each_pair do |attr, param|
         value = self.send(attr)
-        next if value.nil?
+        if value.nil?
+          is_nullable = self.class.openapi_nullable.include?(attr)
+          next if !is_nullable || (is_nullable && !instance_variable_defined?(:"@#{attr}"))
+        end
+        
         hash[param] = _to_hash(value)
       end
       hash