Make all C# flavors support x-zero-based-enum and add tables to documentation (#21463)

* Make all C# flavors support x-zero-based-enum and add table to documentation

* Add the documentation stuff properly

Author: EraYaN

docs/generators/aspnet-fastendpoints.md

@@ -38,6 +38,13 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useValidators|Enable request validators (https://fast-endpoints.com/docs/validation).| |false|
 |versioningPrefix|The versioning prefix for the API. Used only if useApiVersioning is true| |v|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-zero-based-enum|When used on an enum, the index will not be generated and the default numbering will be used, zero-based|MODEL|false
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/aspnetcore.md

@@ -56,6 +56,13 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useSeparateModelProject|Create a separate project for models| |false|
 |useSwashbuckle|Uses the Swashbuckle.AspNetCore NuGet package for documentation.| |true|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-zero-based-enum|When used on an enum, the index will not be generated and the default numbering will be used, zero-based|MODEL|false
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/csharp-functions.md

@@ -48,6 +48,13 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useDateTimeOffset|Use DateTimeOffset to model date-time properties| |false|
 |useNewtonsoft|Uses the Newtonsoft JSON library.| |true|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-zero-based-enum|When used on an enum, the index will not be generated and the default numbering will be used, zero-based|MODEL|false
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

docs/generators/csharp.md

@@ -57,6 +57,13 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |validatable|Generates self-validatable models.| |true|
 |zeroBasedEnums|Enumerations with string values will start from 0 when true, 1 when false. If not set, enumerations with string values will start from 0 if the first value is 'unknown', case insensitive.| |null|
 
+## SUPPORTED VENDOR EXTENSIONS
+
+| Extension name | Description | Applicable for | Default value |
+| -------------- | ----------- | -------------- | ------------- |
+|x-zero-based-enum|When used on an enum, the index will not be generated and the default numbering will be used, zero-based|MODEL|false
+
+
 ## IMPORT MAPPING
 
 | Type/Alias | Imports |

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

@@ -24,6 +24,7 @@ public enum VendorExtension {
     X_OPERATION_EXTRA_ANNOTATION("x-operation-extra-annotation", ExtensionLevel.OPERATION, "List of custom annotations to be added to operation", null),
     X_VERSION_PARAM("x-version-param", ExtensionLevel.OPERATION_PARAMETER, "Marker property that tells that this parameter would be used for endpoint versioning. Applicable for headers & query params. true/false", null),
     X_PATTERN_MESSAGE("x-pattern-message", Arrays.asList(ExtensionLevel.FIELD, ExtensionLevel.OPERATION_PARAMETER), "Add this property whenever you need to customize the invalidation error message for the regex pattern of a variable", null),
+    X_ZERO_BASED_ENUM("x-zero-based-enum", ExtensionLevel.MODEL, "When used on an enum, the index will not be generated and the default numbering will be used, zero-based", "false"),
     ;
 
     private final String name;

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

@@ -105,7 +105,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen {
     protected boolean supportNullable = Boolean.FALSE;
 
     @Setter protected Boolean zeroBasedEnums = null;
-    protected static final String zeroBasedEnumVendorExtension = "x-zero-based-enum";
+    protected static final String zeroBasedEnumVendorExtension = VendorExtension.X_ZERO_BASED_ENUM.getName();
 
     private final Logger LOGGER = LoggerFactory.getLogger(AbstractCSharpCodegen.class);
 
@@ -2103,6 +2103,13 @@ protected Set<String> getNullableTypes() {
         throw new RuntimeException("This method should no longer be used.");
     }
 
+    @Override
+    public List<VendorExtension> getSupportedVendorExtensions() {
+        List<VendorExtension> extensions = super.getSupportedVendorExtensions();
+        extensions.add(VendorExtension.X_ZERO_BASED_ENUM);
+        return extensions;
+    }
+
     protected Set<String> getValueTypes() {
         return new HashSet<>(Arrays.asList("decimal", "bool", "int", "uint", "long", "ulong", "float", "double", "DateTime", "DateOnly", "DateTimeOffset", "Guid"));
     }

modules/openapi-generator/src/main/resources/aspnet-fastendpoints/enumClass.mustache

@@ -11,6 +11,6 @@
         /// <summary>
         /// Enum {{name}} for {{{value}}}
         /// </summary>
-        {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}} = {{-index}}{{/isString}}{{^-last}},
+        {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}}{{^vendorExtensions.x-zero-based-enum}} = {{-index}}{{/vendorExtensions.x-zero-based-enum}}{{/isString}}{{^-last}},
         {{/-last}}{{/enumVars}}{{/allowableValues}}
     }

modules/openapi-generator/src/main/resources/aspnetcore/2.0/enumClass.mustache

@@ -13,6 +13,6 @@
             /// Enum {{name}} for {{{value}}}
             /// </summary>
             {{#isString}}[EnumMember(Value = "{{{value}}}")]{{/isString}}
-            {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}} = {{-index}}{{/isString}}{{^-last}},
+            {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}}{{^vendorExtensions.x-zero-based-enum}} = {{-index}}{{/vendorExtensions.x-zero-based-enum}}{{/isString}}{{^-last}},
             {{/-last}}{{/enumVars}}{{/allowableValues}}
         }

modules/openapi-generator/src/main/resources/aspnetcore/2.1/enumClass.mustache

@@ -14,6 +14,6 @@
             /// Enum {{name}} for {{{value}}}
             /// </summary>
             {{#isString}}[EnumMember(Value = "{{{value}}}")]{{/isString}}
-            {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}} = {{-index}}{{/isString}}{{^-last}},
+            {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}}{{^vendorExtensions.x-zero-based-enum}} = {{-index}}{{/vendorExtensions.x-zero-based-enum}}{{/isString}}{{^-last}},
             {{/-last}}{{/enumVars}}{{/allowableValues}}
         }

modules/openapi-generator/src/main/resources/aspnetcore/3.0/enumClass.mustache

@@ -14,6 +14,6 @@
             /// Enum {{name}} for {{{value}}}
             /// </summary>
             {{#isString}}[EnumMember(Value = "{{{value}}}")]{{/isString}}
-            {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}} = {{-index}}{{/isString}}{{^-last}},
+            {{name}}{{^isString}} = {{{value}}}{{/isString}}{{#isString}}{{^vendorExtensions.x-zero-based-enum}} = {{-index}}{{/vendorExtensions.x-zero-based-enum}}{{/isString}}{{^-last}},
             {{/-last}}{{/enumVars}}{{/allowableValues}}
         }