Add support for required keyword

src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/SchemaGenerator.cs

@@ -67,13 +67,25 @@ private OpenApiSchema GenerateSchemaForMember(
                 if (dataProperty != null)
                 {
                     var requiredAttribute = customAttributes.OfType<RequiredAttribute>().FirstOrDefault();
+
+                    schema.ReadOnly = dataProperty.IsReadOnly;
+                    schema.WriteOnly = dataProperty.IsWriteOnly;
+
+#if NET7_0_OR_GREATER
+                    var hasRequiredMemberAttribute = customAttributes.OfType<System.Runtime.CompilerServices.RequiredMemberAttribute>().Any();
+
+                    schema.Nullable = _generatorOptions.SupportNonNullableReferenceTypes
+                        ? dataProperty.IsNullable && requiredAttribute == null && !hasRequiredMemberAttribute && !memberInfo.IsNonNullableReferenceType()
+                        : dataProperty.IsNullable && requiredAttribute == null && !hasRequiredMemberAttribute;
+
+                    schema.MinLength = modelType == typeof(string) && (hasRequiredMemberAttribute || requiredAttribute is { AllowEmptyStrings: false }) ? 1 : null;
+#else
                     schema.Nullable = _generatorOptions.SupportNonNullableReferenceTypes
                         ? dataProperty.IsNullable && requiredAttribute==null && !memberInfo.IsNonNullableReferenceType()
                         : dataProperty.IsNullable && requiredAttribute==null;
 
-                    schema.ReadOnly = dataProperty.IsReadOnly;
-                    schema.WriteOnly = dataProperty.IsWriteOnly;
                     schema.MinLength = modelType == typeof(string) && requiredAttribute is { AllowEmptyStrings: false } ? 1 : null;
+#endif
                 }
 
                 var defaultValueAttribute = customAttributes.OfType<DefaultValueAttribute>().FirstOrDefault();
@@ -392,7 +404,13 @@ private OpenApiSchema CreateObjectSchema(DataContract dataContract, SchemaReposi
                     ? GenerateSchemaForMember(dataProperty.MemberType, schemaRepository, dataProperty.MemberInfo, dataProperty)
                     : GenerateSchemaForType(dataProperty.MemberType, schemaRepository);
 
-                if ((dataProperty.IsRequired || customAttributes.OfType<RequiredAttribute>().Any())
+                if ((
+                    dataProperty.IsRequired
+                    || customAttributes.OfType<RequiredAttribute>().Any()
+#if NET7_0_OR_GREATER
+                    || customAttributes.OfType<System.Runtime.CompilerServices.RequiredMemberAttribute>().Any()
+#endif
+                    )
                     && !schema.Required.Contains(dataProperty.Name))
                 {
                     schema.Required.Add(dataProperty.Name);

src/Swashbuckle.AspNetCore.SwaggerGen/SwaggerGenerator/ApiParameterDescriptionExtensions.cs

@@ -15,7 +15,10 @@ public static class ApiParameterDescriptionExtensions
         private static readonly Type[] RequiredAttributeTypes = new[]
         {
             typeof(BindRequiredAttribute),
-            typeof(RequiredAttribute)
+            typeof(RequiredAttribute),
+#if NET7_0_OR_GREATER
+            typeof(System.Runtime.CompilerServices.RequiredMemberAttribute)
+#endif
         };
 
         public static bool IsRequiredParameter(this ApiParameterDescription apiParameter)
@@ -109,4 +112,4 @@ internal static bool IsFromForm(this ApiParameterDescription apiParameter)
                 || (elementType != null && typeof(IFormFile).IsAssignableFrom(elementType));
         }
     }
-}
+}

test/Swashbuckle.AspNetCore.SwaggerGen.Test/SchemaGenerator/JsonSerializerSchemaGeneratorTests.cs

@@ -1,20 +1,21 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
 using System.Dynamic;
 using System.Linq;
+using System.Net;
 using System.Text.Json;
 using System.Text.Json.Serialization;
-using System.Net;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.ApiExplorer;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.AspNetCore.Routing.Constraints;
+using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Models;
-using Xunit;
 using Swashbuckle.AspNetCore.TestSupport;
-using Microsoft.OpenApi.Any;
+using Xunit;
 
 namespace Swashbuckle.AspNetCore.SwaggerGen.Test
 {
@@ -343,6 +344,43 @@ public void GenerateSchema_SetsReadOnlyAndWriteOnlyFlags_IfPropertyIsRestricted(
             Assert.True(schema.Properties["WriteOnlyProperty"].WriteOnly);
         }
 
+#if NET7_0_OR_GREATER
+        public class TypeWithRequiredProperty
+        {
+            public required string RequiredProperty { get; set; }
+        }
+
+        public class TypeWithRequiredPropertyAndValidationAttribute
+        {
+            [MinLength(1)]
+            public required string RequiredProperty { get; set; }
+        }
+
+        [Fact]
+        public void GenerateSchema_SetsRequired_IfPropertyHasRequiredKeyword()
+        {
+            var schemaRepository = new SchemaRepository();
+
+            var referenceSchema = Subject().GenerateSchema(typeof(TypeWithRequiredProperty), schemaRepository);
+
+            var schema = schemaRepository.Schemas[referenceSchema.Reference.Id];
+            Assert.Equal(new[] { "RequiredProperty" }, schema.Required.ToArray());
+        }
+
+        [Fact]
+        public void GenerateSchema_SetsRequired_IfPropertyHasRequiredKeywordAndValidationAttribute()
+        {
+            var schemaRepository = new SchemaRepository();
+
+            var referenceSchema = Subject().GenerateSchema(typeof(TypeWithRequiredPropertyAndValidationAttribute), schemaRepository);
+
+            var schema = schemaRepository.Schemas[referenceSchema.Reference.Id];
+            Assert.Equal(1, schema.Properties["RequiredProperty"].MinLength);
+            Assert.False(schema.Properties["RequiredProperty"].Nullable);
+            Assert.Equal(new[] { "RequiredProperty" }, schema.Required.ToArray());
+        }
+#endif
+
         [Theory]
         [InlineData(typeof(TypeWithParameterizedConstructor), nameof(TypeWithParameterizedConstructor.Id), false)]
         [InlineData(typeof(TypeWithParameterlessAndParameterizedConstructor), nameof(TypeWithParameterlessAndParameterizedConstructor.Id), true)]