[C#] Fixed valuetype parameters and discriminator deserialization

Created by: gbrown-ce

• Made non-required valuetypes nullable, and flagged required valuetypes as "x-csharp-value-type"
• Made sure to camelCase discriminator property names in Subtype converter
• Made sure all enum variables are marked as such in the codegen

PR checklist

• Read the contribution guidelines.
• If contributing template-only or documentation-only changes which will change sample output, build the project before.
• Run the shell script(s) under ./bin/ (or Windows batch scripts under.\bin\windows) to update Petstore samples related to your fix. This is important, as CI jobs will verify all generator outputs of your HEAD commit, and these must match the expectations made by your contribution. You only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the code or mustache templates for a language ({LANG}) (e.g. php, ruby, python, etc).
• File the PR against the correct branch: master, 4.3.x, 5.0.x. Default: master.
• Copy the technical committee to review the pull request if your PR is targeting a particular programming language.

@mandrean @jimschubert @frankyjuang @shibayan

This should address these issues: https://github.com/OpenAPITools/openapi-generator/issues/3308 https://github.com/OpenAPITools/openapi-generator/issues/4194

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java

@@ -470,6 +470,32 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
                         var.isPrimitiveType = true;
                     }
                 }
+                for (CodegenProperty var : model.readWriteVars) {
+                    if (enumRefs.containsKey(var.dataType)) {
+                        // Handle any enum properties referred to by $ref.
+                        // This is different in C# than most other generators, because enums in C# are compiled to integral types,
+                        // while enums in many other languages are true objects.
+                        CodegenModel refModel = enumRefs.get(var.dataType);
+                        var.allowableValues = refModel.allowableValues;
+                        var.isEnum = true;
+
+                        // We do these after updateCodegenPropertyEnum to avoid generalities that don't mesh with C#.
+                        var.isPrimitiveType = true;
+                    }
+                }
+                for (CodegenProperty var : model.readOnlyVars) {
+                    if (enumRefs.containsKey(var.dataType)) {
+                        // Handle any enum properties referred to by $ref.
+                        // This is different in C# than most other generators, because enums in C# are compiled to integral types,
+                        // while enums in many other languages are true objects.
+                        CodegenModel refModel = enumRefs.get(var.dataType);
+                        var.allowableValues = refModel.allowableValues;
+                        var.isEnum = true;
+
+                        // We do these after updateCodegenPropertyEnum to avoid generalities that don't mesh with C#.
+                        var.isPrimitiveType = true;
+                    }
+                }
 
                 // We're looping all models here.
                 if (model.isEnum) {

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java

@@ -661,6 +661,14 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
         postProcessPattern(parameter.pattern, parameter.vendorExtensions);
         postProcessEmitDefaultValue(parameter.vendorExtensions);
         super.postProcessParameter(parameter);
+        
+        if (nullableType.contains(parameter.dataType)) {
+            if (!parameter.required) { //optional
+                parameter.dataType = parameter.dataType + "?";
+            } else {
+                parameter.vendorExtensions.put("x-csharp-value-type", true);
+            }
+        }
     }
 
     @Override
@@ -668,6 +676,10 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
         postProcessPattern(property.pattern, property.vendorExtensions);
         postProcessEmitDefaultValue(property.vendorExtensions);
         super.postProcessModelProperty(model, property);
+        
+        if (!property.isContainer && (nullableType.contains(property.dataType) || property.isEnum)) {
+            property.vendorExtensions.put("x-csharp-value-type", true);
+        }
     }
 
     /*

modules/openapi-generator/src/main/resources/csharp/modelGeneric.mustache

@@ -3,7 +3,7 @@
     /// </summary>
     [DataContract]
     {{#discriminator}}
-    [JsonConverter(typeof(JsonSubtypes), "{{{discriminatorName}}}")]{{#children}}
+    [JsonConverter(typeof(JsonSubtypes), "{{#lambda.camelcase_param}}{{{discriminatorName}}}{{/lambda.camelcase_param}}")]{{#children}}
     [JsonSubtypes.KnownSubType(typeof({{classname}}), "{{^vendorExtensions.x-discriminator-value}}{{name}}{{/vendorExtensions.x-discriminator-value}}{{#vendorExtensions.x-discriminator-value}}{{{vendorExtensions.x-discriminator-value}}}{{/vendorExtensions.x-discriminator-value}}")]{{/children}}
     {{/discriminator}}
     {{#generatePropertyChanged}}
@@ -31,7 +31,7 @@
         {{#description}}
         /// <value>{{description}}</value>
         {{/description}}
-        [DataMember(Name="{{baseName}}", EmitDefaultValue={{#vendorExtensions.x-emit-default-value}}true{{/vendorExtensions.x-emit-default-value}}{{^vendorExtensions.x-emit-default-value}}{{#isNullable}}true{{/isNullable}}{{^isNullable}}false{{/isNullable}}{{/vendorExtensions.x-emit-default-value}})]
+        [DataMember(Name="{{baseName}}", EmitDefaultValue={{#vendorExtensions.x-emit-default-value}}true{{/vendorExtensions.x-emit-default-value}}{{^vendorExtensions.x-emit-default-value}}{{#isNullable}}true{{/isNullable}}{{^isNullable}}{{#required}}true{{/required}}{{^required}}false{{/required}}{{/isNullable}}{{/vendorExtensions.x-emit-default-value}})]
         public {{#complexType}}{{{complexType}}}{{/complexType}}{{^complexType}}{{{datatypeWithEnum}}}{{/complexType}}{{^isContainer}}{{^required}}?{{/required}}{{/isContainer}} {{name}} { get; set; }
         {{/isEnum}}
         {{/vars}}
@@ -108,7 +108,7 @@ this.{{name}} = {{#lambda.camelcase_param}}{{name}}{{/lambda.camelcase_param}};
         /// {{^description}}Gets or Sets {{{name}}}{{/description}}{{#description}}{{description}}{{/description}}
         /// </summary>{{#description}}
         /// <value>{{description}}</value>{{/description}}
-        [DataMember(Name="{{baseName}}", EmitDefaultValue={{#vendorExtensions.x-emit-default-value}}true{{/vendorExtensions.x-emit-default-value}}{{^vendorExtensions.x-emit-default-value}}{{#isNullable}}true{{/isNullable}}{{^isNullable}}false{{/isNullable}}{{/vendorExtensions.x-emit-default-value}})]{{#isDate}}
+        [DataMember(Name="{{baseName}}", EmitDefaultValue={{#vendorExtensions.x-emit-default-value}}true{{/vendorExtensions.x-emit-default-value}}{{^vendorExtensions.x-emit-default-value}}{{#isNullable}}true{{/isNullable}}{{^isNullable}}{{#required}}true{{/required}}{{^required}}false{{/required}}{{/isNullable}}{{/vendorExtensions.x-emit-default-value}})]{{#isDate}}
         [JsonConverter(typeof(OpenAPIDateConverter))]{{/isDate}}
         public {{{dataType}}} {{name}} { get; {{#isReadOnly}}private {{/isReadOnly}}set; }
         {{/isEnum}}

samples/client/petstore/csharp/OpenAPIClient/docs/FakeApi.md

@@ -97,7 +97,7 @@ No authorization required
 
 ## FakeOuterBooleanSerialize
 
-> bool FakeOuterBooleanSerialize (bool body = null)
+> bool FakeOuterBooleanSerialize (bool? body = null)
 
 
 
@@ -120,7 +120,7 @@ namespace Example
         {
             Configuration.Default.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(Configuration.Default);
-            var body = true;  // bool | Input boolean as post body (optional) 
+            var body = true;  // bool? | Input boolean as post body (optional) 
 
             try
             {
@@ -143,7 +143,7 @@ namespace Example
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | **bool**| Input boolean as post body | [optional] 
+ **body** | **bool?**| Input boolean as post body | [optional] 
 
 ### Return type
 
@@ -245,7 +245,7 @@ No authorization required
 
 ## FakeOuterNumberSerialize
 
-> decimal FakeOuterNumberSerialize (decimal body = null)
+> decimal FakeOuterNumberSerialize (decimal? body = null)
 
 
 
@@ -268,7 +268,7 @@ namespace Example
         {
             Configuration.Default.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(Configuration.Default);
-            var body = 8.14;  // decimal | Input number as post body (optional) 
+            var body = 8.14;  // decimal? | Input number as post body (optional) 
 
             try
             {
@@ -291,7 +291,7 @@ namespace Example
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **body** | **decimal**| Input number as post body | [optional] 
+ **body** | **decimal?**| Input number as post body | [optional] 
 
 ### Return type
 
@@ -614,7 +614,7 @@ No authorization required
 
 ## TestEndpointParameters
 
-> void TestEndpointParameters (decimal number, double _double, string patternWithoutDelimiter, byte[] _byte, int integer = null, int int32 = null, long int64 = null, float _float = null, string _string = null, System.IO.Stream binary = null, DateTime date = null, DateTime dateTime = null, string password = null, string callback = null)
+> void TestEndpointParameters (decimal number, double _double, string patternWithoutDelimiter, byte[] _byte, int? integer = null, int? int32 = null, long? int64 = null, float? _float = null, string _string = null, System.IO.Stream binary = null, DateTime? date = null, DateTime? dateTime = null, string password = null, string callback = null)
 
 Fake endpoint for testing various parameters  假端點  偽のエンドポイント  가짜 엔드 포인트
 
@@ -645,14 +645,14 @@ namespace Example
             var _double = 1.2D;  // double | None
             var patternWithoutDelimiter = patternWithoutDelimiter_example;  // string | None
             var _byte = BYTE_ARRAY_DATA_HERE;  // byte[] | None
-            var integer = 56;  // int | None (optional) 
-            var int32 = 56;  // int | None (optional) 
-            var int64 = 789;  // long | None (optional) 
-            var _float = 3.4F;  // float | None (optional) 
+            var integer = 56;  // int? | None (optional) 
+            var int32 = 56;  // int? | None (optional) 
+            var int64 = 789;  // long? | None (optional) 
+            var _float = 3.4F;  // float? | None (optional) 
             var _string = _string_example;  // string | None (optional) 
             var binary = BINARY_DATA_HERE;  // System.IO.Stream | None (optional) 
-            var date = 2013-10-20;  // DateTime | None (optional) 
-            var dateTime = 2013-10-20T19:20:30+01:00;  // DateTime | None (optional) 
+            var date = 2013-10-20;  // DateTime? | None (optional) 
+            var dateTime = 2013-10-20T19:20:30+01:00;  // DateTime? | None (optional) 
             var password = password_example;  // string | None (optional) 
             var callback = callback_example;  // string | None (optional) 
 
@@ -681,14 +681,14 @@ Name | Type | Description  | Notes
  **_double** | **double**| None | 
  **patternWithoutDelimiter** | **string**| None | 
  **_byte** | **byte[]**| None | 
- **integer** | **int**| None | [optional] 
- **int32** | **int**| None | [optional] 
- **int64** | **long**| None | [optional] 
- **_float** | **float**| None | [optional] 
+ **integer** | **int?**| None | [optional] 
+ **int32** | **int?**| None | [optional] 
+ **int64** | **long?**| None | [optional] 
+ **_float** | **float?**| None | [optional] 
  **_string** | **string**| None | [optional] 
  **binary** | **System.IO.Stream**| None | [optional] 
- **date** | **DateTime**| None | [optional] 
- **dateTime** | **DateTime**| None | [optional] 
+ **date** | **DateTime?**| None | [optional] 
+ **dateTime** | **DateTime?**| None | [optional] 
  **password** | **string**| None | [optional] 
  **callback** | **string**| None | [optional] 
 
@@ -719,7 +719,7 @@ void (empty response body)
 
 ## TestEnumParameters
 
-> void TestEnumParameters (List<string> enumHeaderStringArray = null, string enumHeaderString = null, List<string> enumQueryStringArray = null, string enumQueryString = null, int enumQueryInteger = null, double enumQueryDouble = null, List<string> enumFormStringArray = null, string enumFormString = null)
+> void TestEnumParameters (List<string> enumHeaderStringArray = null, string enumHeaderString = null, List<string> enumQueryStringArray = null, string enumQueryString = null, int? enumQueryInteger = null, double? enumQueryDouble = null, List<string> enumFormStringArray = null, string enumFormString = null)
 
 To test enum parameters
 
@@ -746,8 +746,8 @@ namespace Example
             var enumHeaderString = enumHeaderString_example;  // string | Header parameter enum test (string) (optional)  (default to -efg)
             var enumQueryStringArray = enumQueryStringArray_example;  // List<string> | Query parameter enum test (string array) (optional) 
             var enumQueryString = enumQueryString_example;  // string | Query parameter enum test (string) (optional)  (default to -efg)
-            var enumQueryInteger = 56;  // int | Query parameter enum test (double) (optional) 
-            var enumQueryDouble = 1.2D;  // double | Query parameter enum test (double) (optional) 
+            var enumQueryInteger = 56;  // int? | Query parameter enum test (double) (optional) 
+            var enumQueryDouble = 1.2D;  // double? | Query parameter enum test (double) (optional) 
             var enumFormStringArray = new List<string>(); // List<string> | Form parameter enum test (string array) (optional)  (default to $)
             var enumFormString = enumFormString_example;  // string | Form parameter enum test (string) (optional)  (default to -efg)
 
@@ -776,8 +776,8 @@ Name | Type | Description  | Notes
  **enumHeaderString** | **string**| Header parameter enum test (string) | [optional] [default to -efg]
  **enumQueryStringArray** | **List&lt;string&gt;**| Query parameter enum test (string array) | [optional] 
  **enumQueryString** | **string**| Query parameter enum test (string) | [optional] [default to -efg]
- **enumQueryInteger** | **int**| Query parameter enum test (double) | [optional] 
- **enumQueryDouble** | **double**| Query parameter enum test (double) | [optional] 
+ **enumQueryInteger** | **int?**| Query parameter enum test (double) | [optional] 
+ **enumQueryDouble** | **double?**| Query parameter enum test (double) | [optional] 
  **enumFormStringArray** | [**List&lt;string&gt;**](string.md)| Form parameter enum test (string array) | [optional] [default to $]
  **enumFormString** | **string**| Form parameter enum test (string) | [optional] [default to -efg]
 
@@ -808,7 +808,7 @@ No authorization required
 
 ## TestGroupParameters
 
-> void TestGroupParameters (int requiredStringGroup, bool requiredBooleanGroup, long requiredInt64Group, int stringGroup = null, bool booleanGroup = null, long int64Group = null)
+> void TestGroupParameters (int requiredStringGroup, bool requiredBooleanGroup, long requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
 
 Fake endpoint to test group parameters (optional)
 
@@ -834,9 +834,9 @@ namespace Example
             var requiredStringGroup = 56;  // int | Required String in group parameters
             var requiredBooleanGroup = true;  // bool | Required Boolean in group parameters
             var requiredInt64Group = 789;  // long | Required Integer in group parameters
-            var stringGroup = 56;  // int | String in group parameters (optional) 
-            var booleanGroup = true;  // bool | Boolean in group parameters (optional) 
-            var int64Group = 789;  // long | Integer in group parameters (optional) 
+            var stringGroup = 56;  // int? | String in group parameters (optional) 
+            var booleanGroup = true;  // bool? | Boolean in group parameters (optional) 
+            var int64Group = 789;  // long? | Integer in group parameters (optional) 
 
             try
             {
@@ -862,9 +862,9 @@ Name | Type | Description  | Notes
  **requiredStringGroup** | **int**| Required String in group parameters | 
  **requiredBooleanGroup** | **bool**| Required Boolean in group parameters | 
  **requiredInt64Group** | **long**| Required Integer in group parameters | 
- **stringGroup** | **int**| String in group parameters | [optional] 
- **booleanGroup** | **bool**| Boolean in group parameters | [optional] 
- **int64Group** | **long**| Integer in group parameters | [optional] 
+ **stringGroup** | **int?**| String in group parameters | [optional] 
+ **booleanGroup** | **bool?**| Boolean in group parameters | [optional] 
+ **int64Group** | **long?**| Integer in group parameters | [optional] 
 
 ### Return type