diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
index f5830ce1e57..137805cde1b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
@@ -607,6 +607,7 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
 
         this.operationIdNaming = operationIdNaming;
     }
+
     @Override
     public String escapeQuotationMark(String input) {
         // remove " to avoid code injection
@@ -952,8 +953,8 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
         }
 
         // remove trailing '/'
-        if (pattern.charAt(pattern.length()-1) == '/') {
-            pattern = pattern.substring(0, pattern.length()-1);
+        if (pattern.charAt(pattern.length() - 1) == '/') {
+            pattern = pattern.substring(0, pattern.length() - 1);
         }
 
         return escapeText(pattern);
diff --git a/modules/openapi-generator/src/main/resources/r/api.mustache b/modules/openapi-generator/src/main/resources/r/api.mustache
index 527b62d4eb2..1b93f6119c2 100644
--- a/modules/openapi-generator/src/main/resources/r/api.mustache
+++ b/modules/openapi-generator/src/main/resources/r/api.mustache
@@ -573,4 +573,4 @@
     {{/operation}}
   )
 )
-{{/operations}}
+{{/operations}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
index 129530a51f3..a608280e8cd 100644
--- a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
+++ b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
@@ -354,6 +354,125 @@
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      {{#allVars}}
+      {{^isNullable}}
+      {{#required}}
+      # check if the required `{{{name}}}` is null
+      if (is.null(`{{{name}}}`)) {
+        FALSE
+      }
+
+      {{/required}}
+      {{/isNullable}}
+      {{#hasValidation}}
+      {{#maxLength}}
+      if (nchar(`{{{name}}}`) > {{maxLength}}) {
+        FALSE
+      }
+      {{/maxLength}}
+      {{#minLength}}
+      if (nchar(`{{{name}}}`) < {{minLength}}) {
+        FALSE
+      }
+      {{/minLength}}
+      {{#maximum}}
+      if (`{{{name}}}` >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{maximum}}) {
+        FALSE
+      }
+      {{/maximum}}
+      {{#minimum}}
+      if (`{{{name}}}` <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{minimum}}) {
+        FALSE
+      }
+      {{/minimum}}
+      {{#pattern}}
+      if (!str_detect(`{{{name}}}`, "{{{pattern}}}")) {
+        FALSE
+      }
+      {{/pattern}}
+      {{#maxItems}}
+      if (length(`{{{name}}}`) > {{maxItems}}) {
+        FALSE
+      }
+      {{/maxItems}}
+      {{#minItems}}
+      if (length(`{{{name}}}`) < {{minItems}}) {
+        FALSE
+      }
+      {{/minItems}}
+
+      {{/hasValidation}}
+      {{/allVars}}
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      {{#allVars}}
+      {{^isNullable}}
+      {{#required}}
+      # check if the required `{{{name}}}` is null
+      if (is.null(`{{{name}}}`)) {
+        invalid_fields[`{{{name}}}`] = "Non-nullable required field `{{{name}}}` cannot be null."
+      }
+
+      {{/required}}
+      {{/isNullable}}
+      {{#hasValidation}}
+      {{#maxLength}}
+      if (nchar(`{{{name}}}`) > {{maxLength}}) {
+        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{name}}}`, must be smaller than or equal to {{maxLength}}."
+      }
+      {{/maxLength}}
+      {{#minLength}}
+      if (nchar(`{{{name}}}`) < {{minLength}}) {
+        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{name}}}`, must be bigger than or equal to {{minLength}}."
+      }
+      {{/minLength}}
+      {{#maximum}}
+      if (`{{{name}}}` >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{maximum}}) {
+        invalid_fields[`{{{name}}}`] = "Invalid value for `{{{name}}}`, must be smaller than {{^exclusiveMaximum}}or equal to {{/exclusiveMaximum}}{{maximum}}."
+      }
+      {{/maximum}}
+      {{#minimum}}
+      if (`{{{name}}}` <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{minimum}}) {
+        invalid_fields[`{{{name}}}`] = "Invalid value for `{{{name}}}`, must be bigger than {{^exclusiveMinimum}}or equal to {{/exclusiveMinimum}}{{minimum}}."
+      }
+      {{/minimum}}
+      {{#pattern}}
+      if (!str_detect(`{{{name}}}`, "{{{pattern}}}")) {
+        invalid_fields[`{{{name}}}`] = "Invalid value for `{{{name}}}`, must conform to the pattern {{{pattern}}}."
+      }
+      {{/pattern}}
+      {{#maxItems}}
+      if (length(`{{{name}}}`) > {{maxItems}}) {
+        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{name}}}`, number of items must be less than or equal to {{maxItems}}."
+      }
+      {{/maxItems}}
+      {{#minItems}}
+      if (length(`{{{name}}}`) < {{minItems}}) {
+        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{param}}}`, number of items must be greater than or equal to {{minItems}}."
+      }
+      {{/minItems}}
+
+      {{/hasValidation}}
+      {{/allVars}}
+      invalid_fields
     }
   )
 )
\ No newline at end of file
diff --git a/samples/client/petstore/R-httr2/R/allof_tag_api_response.R b/samples/client/petstore/R-httr2/R/allof_tag_api_response.R
index 8cae653d3e6..8a148dbd067 100644
--- a/samples/client/petstore/R-httr2/R/allof_tag_api_response.R
+++ b/samples/client/petstore/R-httr2/R/allof_tag_api_response.R
@@ -210,6 +210,27 @@ AllofTagApiResponse <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/animal.R b/samples/client/petstore/R-httr2/R/animal.R
index 3640667985a..9189e9c1597 100644
--- a/samples/client/petstore/R-httr2/R/animal.R
+++ b/samples/client/petstore/R-httr2/R/animal.R
@@ -147,6 +147,37 @@ Animal <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/basque_pig.R b/samples/client/petstore/R-httr2/R/basque_pig.R
index 0324d48c10a..3a4ca70654e 100644
--- a/samples/client/petstore/R-httr2/R/basque_pig.R
+++ b/samples/client/petstore/R-httr2/R/basque_pig.R
@@ -153,6 +153,47 @@ BasquePig <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      # check if the required `color` is null
+      if (is.null(`color`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      # check if the required `color` is null
+      if (is.null(`color`)) {
+        invalid_fields[`color`] = "Non-nullable required field `color` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/cat.R b/samples/client/petstore/R-httr2/R/cat.R
index 1ec34dc4a75..1d9a7017f55 100644
--- a/samples/client/petstore/R-httr2/R/cat.R
+++ b/samples/client/petstore/R-httr2/R/cat.R
@@ -171,6 +171,37 @@ Cat <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/cat_all_of.R b/samples/client/petstore/R-httr2/R/cat_all_of.R
index 063ece351fd..8f6055ccd29 100644
--- a/samples/client/petstore/R-httr2/R/cat_all_of.R
+++ b/samples/client/petstore/R-httr2/R/cat_all_of.R
@@ -118,6 +118,27 @@ CatAllOf <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/category.R b/samples/client/petstore/R-httr2/R/category.R
index 051506bbc9e..0bd55f34ce2 100644
--- a/samples/client/petstore/R-httr2/R/category.R
+++ b/samples/client/petstore/R-httr2/R/category.R
@@ -141,6 +141,35 @@ Category <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        invalid_fields[`name`] = "Invalid value for `name`, must conform to the pattern ^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/danish_pig.R b/samples/client/petstore/R-httr2/R/danish_pig.R
index 97eef4cda57..a7584f4700b 100644
--- a/samples/client/petstore/R-httr2/R/danish_pig.R
+++ b/samples/client/petstore/R-httr2/R/danish_pig.R
@@ -153,6 +153,47 @@ DanishPig <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      # check if the required `size` is null
+      if (is.null(`size`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      # check if the required `size` is null
+      if (is.null(`size`)) {
+        invalid_fields[`size`] = "Non-nullable required field `size` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/dog.R b/samples/client/petstore/R-httr2/R/dog.R
index b52f75ccbae..59f39c2e091 100644
--- a/samples/client/petstore/R-httr2/R/dog.R
+++ b/samples/client/petstore/R-httr2/R/dog.R
@@ -171,6 +171,37 @@ Dog <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/dog_all_of.R b/samples/client/petstore/R-httr2/R/dog_all_of.R
index 8f4328feb28..8956ffc3771 100644
--- a/samples/client/petstore/R-httr2/R/dog_all_of.R
+++ b/samples/client/petstore/R-httr2/R/dog_all_of.R
@@ -118,6 +118,27 @@ DogAllOf <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/model_api_response.R b/samples/client/petstore/R-httr2/R/model_api_response.R
index a5b39c53444..713ab123bb7 100644
--- a/samples/client/petstore/R-httr2/R/model_api_response.R
+++ b/samples/client/petstore/R-httr2/R/model_api_response.R
@@ -164,6 +164,27 @@ ModelApiResponse <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/nested_one_of.R b/samples/client/petstore/R-httr2/R/nested_one_of.R
index 0c86dbd7075..95840db010f 100644
--- a/samples/client/petstore/R-httr2/R/nested_one_of.R
+++ b/samples/client/petstore/R-httr2/R/nested_one_of.R
@@ -143,6 +143,27 @@ NestedOneOf <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/order.R b/samples/client/petstore/R-httr2/R/order.R
index 3d342c3a4f7..892cb94a4d4 100644
--- a/samples/client/petstore/R-httr2/R/order.R
+++ b/samples/client/petstore/R-httr2/R/order.R
@@ -233,6 +233,27 @@ Order <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/pet.R b/samples/client/petstore/R-httr2/R/pet.R
index 08a0dd66ac5..e8537ad77d0 100644
--- a/samples/client/petstore/R-httr2/R/pet.R
+++ b/samples/client/petstore/R-httr2/R/pet.R
@@ -250,6 +250,47 @@ Pet <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `name` is null
+      if (is.null(`name`)) {
+        FALSE
+      }
+
+      # check if the required `photoUrls` is null
+      if (is.null(`photoUrls`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `name` is null
+      if (is.null(`name`)) {
+        invalid_fields[`name`] = "Non-nullable required field `name` cannot be null."
+      }
+
+      # check if the required `photoUrls` is null
+      if (is.null(`photoUrls`)) {
+        invalid_fields[`photoUrls`] = "Non-nullable required field `photoUrls` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/special.R b/samples/client/petstore/R-httr2/R/special.R
index 0680b7f193d..5027b80757e 100644
--- a/samples/client/petstore/R-httr2/R/special.R
+++ b/samples/client/petstore/R-httr2/R/special.R
@@ -233,6 +233,27 @@ Special <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/tag.R b/samples/client/petstore/R-httr2/R/tag.R
index 015063f7191..e0cff8390fe 100644
--- a/samples/client/petstore/R-httr2/R/tag.R
+++ b/samples/client/petstore/R-httr2/R/tag.R
@@ -141,6 +141,27 @@ Tag <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/update_pet_request.R b/samples/client/petstore/R-httr2/R/update_pet_request.R
index de949b175ca..fd573b5a8e3 100644
--- a/samples/client/petstore/R-httr2/R/update_pet_request.R
+++ b/samples/client/petstore/R-httr2/R/update_pet_request.R
@@ -142,6 +142,27 @@ UpdatePetRequest <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R-httr2/R/user.R b/samples/client/petstore/R-httr2/R/user.R
index 541b1ba0332..e99de33bdfc 100644
--- a/samples/client/petstore/R-httr2/R/user.R
+++ b/samples/client/petstore/R-httr2/R/user.R
@@ -279,6 +279,27 @@ User <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/allof_tag_api_response.R b/samples/client/petstore/R/R/allof_tag_api_response.R
index 8cae653d3e6..8a148dbd067 100644
--- a/samples/client/petstore/R/R/allof_tag_api_response.R
+++ b/samples/client/petstore/R/R/allof_tag_api_response.R
@@ -210,6 +210,27 @@ AllofTagApiResponse <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/animal.R b/samples/client/petstore/R/R/animal.R
index 3640667985a..9189e9c1597 100644
--- a/samples/client/petstore/R/R/animal.R
+++ b/samples/client/petstore/R/R/animal.R
@@ -147,6 +147,37 @@ Animal <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/basque_pig.R b/samples/client/petstore/R/R/basque_pig.R
index 0324d48c10a..3a4ca70654e 100644
--- a/samples/client/petstore/R/R/basque_pig.R
+++ b/samples/client/petstore/R/R/basque_pig.R
@@ -153,6 +153,47 @@ BasquePig <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      # check if the required `color` is null
+      if (is.null(`color`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      # check if the required `color` is null
+      if (is.null(`color`)) {
+        invalid_fields[`color`] = "Non-nullable required field `color` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/cat.R b/samples/client/petstore/R/R/cat.R
index 1ec34dc4a75..1d9a7017f55 100644
--- a/samples/client/petstore/R/R/cat.R
+++ b/samples/client/petstore/R/R/cat.R
@@ -171,6 +171,37 @@ Cat <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/cat_all_of.R b/samples/client/petstore/R/R/cat_all_of.R
index 063ece351fd..8f6055ccd29 100644
--- a/samples/client/petstore/R/R/cat_all_of.R
+++ b/samples/client/petstore/R/R/cat_all_of.R
@@ -118,6 +118,27 @@ CatAllOf <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/category.R b/samples/client/petstore/R/R/category.R
index 051506bbc9e..0bd55f34ce2 100644
--- a/samples/client/petstore/R/R/category.R
+++ b/samples/client/petstore/R/R/category.R
@@ -141,6 +141,35 @@ Category <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        invalid_fields[`name`] = "Invalid value for `name`, must conform to the pattern ^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/danish_pig.R b/samples/client/petstore/R/R/danish_pig.R
index 97eef4cda57..a7584f4700b 100644
--- a/samples/client/petstore/R/R/danish_pig.R
+++ b/samples/client/petstore/R/R/danish_pig.R
@@ -153,6 +153,47 @@ DanishPig <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      # check if the required `size` is null
+      if (is.null(`size`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      # check if the required `size` is null
+      if (is.null(`size`)) {
+        invalid_fields[`size`] = "Non-nullable required field `size` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/dog.R b/samples/client/petstore/R/R/dog.R
index b52f75ccbae..59f39c2e091 100644
--- a/samples/client/petstore/R/R/dog.R
+++ b/samples/client/petstore/R/R/dog.R
@@ -171,6 +171,37 @@ Dog <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `className` is null
+      if (is.null(`className`)) {
+        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/dog_all_of.R b/samples/client/petstore/R/R/dog_all_of.R
index 8f4328feb28..8956ffc3771 100644
--- a/samples/client/petstore/R/R/dog_all_of.R
+++ b/samples/client/petstore/R/R/dog_all_of.R
@@ -118,6 +118,27 @@ DogAllOf <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/model_api_response.R b/samples/client/petstore/R/R/model_api_response.R
index a5b39c53444..713ab123bb7 100644
--- a/samples/client/petstore/R/R/model_api_response.R
+++ b/samples/client/petstore/R/R/model_api_response.R
@@ -164,6 +164,27 @@ ModelApiResponse <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/nested_one_of.R b/samples/client/petstore/R/R/nested_one_of.R
index 0c86dbd7075..95840db010f 100644
--- a/samples/client/petstore/R/R/nested_one_of.R
+++ b/samples/client/petstore/R/R/nested_one_of.R
@@ -143,6 +143,27 @@ NestedOneOf <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/order.R b/samples/client/petstore/R/R/order.R
index 3d342c3a4f7..892cb94a4d4 100644
--- a/samples/client/petstore/R/R/order.R
+++ b/samples/client/petstore/R/R/order.R
@@ -233,6 +233,27 @@ Order <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/pet.R b/samples/client/petstore/R/R/pet.R
index 08a0dd66ac5..e8537ad77d0 100644
--- a/samples/client/petstore/R/R/pet.R
+++ b/samples/client/petstore/R/R/pet.R
@@ -250,6 +250,47 @@ Pet <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      # check if the required `name` is null
+      if (is.null(`name`)) {
+        FALSE
+      }
+
+      # check if the required `photoUrls` is null
+      if (is.null(`photoUrls`)) {
+        FALSE
+      }
+
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      # check if the required `name` is null
+      if (is.null(`name`)) {
+        invalid_fields[`name`] = "Non-nullable required field `name` cannot be null."
+      }
+
+      # check if the required `photoUrls` is null
+      if (is.null(`photoUrls`)) {
+        invalid_fields[`photoUrls`] = "Non-nullable required field `photoUrls` cannot be null."
+      }
+
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/special.R b/samples/client/petstore/R/R/special.R
index 0680b7f193d..5027b80757e 100644
--- a/samples/client/petstore/R/R/special.R
+++ b/samples/client/petstore/R/R/special.R
@@ -233,6 +233,27 @@ Special <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/tag.R b/samples/client/petstore/R/R/tag.R
index 015063f7191..e0cff8390fe 100644
--- a/samples/client/petstore/R/R/tag.R
+++ b/samples/client/petstore/R/R/tag.R
@@ -141,6 +141,27 @@ Tag <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/update_pet_request.R b/samples/client/petstore/R/R/update_pet_request.R
index de949b175ca..fd573b5a8e3 100644
--- a/samples/client/petstore/R/R/update_pet_request.R
+++ b/samples/client/petstore/R/R/update_pet_request.R
@@ -142,6 +142,27 @@ UpdatePetRequest <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )
diff --git a/samples/client/petstore/R/R/user.R b/samples/client/petstore/R/R/user.R
index 541b1ba0332..e99de33bdfc 100644
--- a/samples/client/petstore/R/R/user.R
+++ b/samples/client/petstore/R/R/user.R
@@ -279,6 +279,27 @@ User <- R6::R6Class(
     #' @export
     toString = function() {
       self$toJSONString()
+    },
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @description
+    #' Return true if the values in all fields are valid.
+    #'
+    #' @return true if the values in all fields are valid.
+    #' @export
+    isValid = function() {
+      TRUE
+    },
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @description
+    #' Return a list of invalid fields (if any).
+    #'
+    #' @return A list of invalid fields (if any).
+    #' @export
+    getInvalidFields = function() {
+      invalid_fields <- list()
+      invalid_fields
     }
   )
 )