Use StatusCodes constants instead of literals in the ProducesResponseType code fix (#8234)

* Use StatusCodes constants instead of literals

src/Microsoft.AspNetCore.Mvc.Api.Analyzers/AddResponseTypeAttributeCodeFixAction.cs

@@ -40,9 +40,12 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
             }
 
             var documentEditor = await DocumentEditor.CreateAsync(_document, cancellationToken).ConfigureAwait(false);
+
+            var addUsingDirective = false;
             foreach (var statusCode in statusCodes.OrderBy(s => s))
             {
-                documentEditor.AddAttribute(context.MethodSyntax, CreateProducesResponseTypeAttribute(statusCode));
+                documentEditor.AddAttribute(context.MethodSyntax, CreateProducesResponseTypeAttribute(context, statusCode, out var addUsing));
+                addUsingDirective |= addUsing;
             }
 
             if (!declaredResponseMetadata.Any(m => m.IsDefault && m.AttributeSource == context.Method))
@@ -64,7 +67,23 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
                 documentEditor.RemoveNode(attributeSyntax);
             }
 
-            return documentEditor.GetChangedDocument();
+            var document = documentEditor.GetChangedDocument();
+
+            var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+
+            if (root is CompilationUnitSyntax compilationUnit && addUsingDirective)
+            {
+                const string @namespace = "Microsoft.AspNetCore.Http";
+
+                var declaredUsings = new HashSet<string>(compilationUnit.Usings.Select(x => x.Name.ToString()));
+
+                if (!declaredUsings.Contains(@namespace))
+                {
+                    root = compilationUnit.AddUsings(SyntaxFactory.UsingDirective(SyntaxFactory.ParseName(@namespace)));
+                }
+            }
+
+            return document.WithSyntaxRoot(root);
         }
 
         private async Task<CodeActionContext> CreateCodeActionContext(CancellationToken cancellationToken)
@@ -75,12 +94,37 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
             var methodSyntax = methodReturnStatement.FirstAncestorOrSelf<MethodDeclarationSyntax>();
             var method = semanticModel.GetDeclaredSymbol(methodSyntax, cancellationToken);
 
+            var statusCodesType = semanticModel.Compilation.GetTypeByMetadataName(ApiSymbolNames.HttpStatusCodes);
+            var statusCodeConstants = GetStatusCodeConstants(statusCodesType);
+
             var symbolCache = new ApiControllerSymbolCache(semanticModel.Compilation);
 
-            var codeActionContext = new CodeActionContext(semanticModel, symbolCache, method, methodSyntax, cancellationToken);
+            var codeActionContext = new CodeActionContext(semanticModel, symbolCache, method, methodSyntax, statusCodeConstants, cancellationToken);
             return codeActionContext;
         }
 
+        private static Dictionary<int, string> GetStatusCodeConstants(INamespaceOrTypeSymbol statusCodesType)
+        {
+            var statusCodeConstants = new Dictionary<int, string>();
+
+            if (statusCodesType != null)
+            {
+                foreach (var member in statusCodesType.GetMembers())
+                {
+                    if (member is IFieldSymbol field &&
+                        field.Type.SpecialType == SpecialType.System_Int32 &&
+                        field.Name.StartsWith("Status") &&
+                        field.HasConstantValue &&
+                        field.ConstantValue is int statusCode)
+                    {
+                        statusCodeConstants[statusCode] = field.Name;
+                    }
+                }
+            }
+
+            return statusCodeConstants;
+        }
+
         private ICollection<int> CalculateStatusCodesToApply(CodeActionContext context, IList<DeclaredApiResponseMetadata> declaredResponseMetadata)
         {
             if (!SymbolApiResponseMetadataProvider.TryGetActualResponseMetadata(context.SymbolCache, context.SemanticModel, context.MethodSyntax, context.CancellationToken, out var actualResponseMetadata))
@@ -105,14 +149,31 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
             return statusCodes;
         }
 
-        private static AttributeSyntax CreateProducesResponseTypeAttribute(int statusCode)
+        private static AttributeSyntax CreateProducesResponseTypeAttribute(CodeActionContext context, int statusCode, out bool addUsingDirective)
         {
+            var statusCodeSyntax = CreateStatusCodeSyntax(context, statusCode, out addUsingDirective);
+
             return SyntaxFactory.Attribute(
                 SyntaxFactory.ParseName(ApiSymbolNames.ProducesResponseTypeAttribute)
                     .WithAdditionalAnnotations(Simplifier.Annotation),
                 SyntaxFactory.AttributeArgumentList().AddArguments(
-                    SyntaxFactory.AttributeArgument(
+                    SyntaxFactory.AttributeArgument(statusCodeSyntax)));
-                        SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(statusCode)))));
+        }
+
+        private static ExpressionSyntax CreateStatusCodeSyntax(CodeActionContext context, int statusCode, out bool addUsingDirective)
+        {
+            if (context.StatusCodeConstants.TryGetValue(statusCode, out var constantName))
+            {
+                addUsingDirective = true;
+                return SyntaxFactory.MemberAccessExpression(
+                    SyntaxKind.SimpleMemberAccessExpression,
+                    SyntaxFactory.ParseTypeName(ApiSymbolNames.HttpStatusCodes)
+                        .WithAdditionalAnnotations(Simplifier.Annotation),
+                    SyntaxFactory.IdentifierName(constantName));
+            }
+
+            addUsingDirective = false;
+            return SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(statusCode));
         }
 
         private static AttributeSyntax CreateProducesDefaultResponseTypeAttribute()
@@ -124,22 +185,25 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
 
         private readonly struct CodeActionContext
         {
-            public CodeActionContext(
+            public CodeActionContext(SemanticModel semanticModel,
-                SemanticModel semanticModel,
                 ApiControllerSymbolCache symbolCache,
                 IMethodSymbol method,
                 MethodDeclarationSyntax methodSyntax,
+                Dictionary<int, string> statusCodeConstants,
                 CancellationToken cancellationToken)
             {
                 SemanticModel = semanticModel;
                 SymbolCache = symbolCache;
                 Method = method;
                 MethodSyntax = methodSyntax;
+                StatusCodeConstants = statusCodeConstants;
                 CancellationToken = cancellationToken;
             }
 
             public MethodDeclarationSyntax MethodSyntax { get; }
 
+            public Dictionary<int, string> StatusCodeConstants { get; }
+
             public IMethodSymbol Method { get; }
 
             public SemanticModel SemanticModel { get; }

src/Microsoft.AspNetCore.Mvc.Api.Analyzers/ApiSymbolNames.cs

@@ -32,5 +32,7 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers
         public const string ProducesDefaultResponseTypeAttribute = "Microsoft.AspNetCore.Mvc.ProducesDefaultResponseTypeAttribute";
 
         public const string ProducesResponseTypeAttribute = "Microsoft.AspNetCore.Mvc.ProducesResponseTypeAttribute";
+
+        public const string HttpStatusCodes = "Microsoft.AspNetCore.Http.StatusCodes";
     }
 }

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsFullyQualifiedProducesResponseType.Output.cs

@@ -1,4 +1,5 @@
-
+using Microsoft.AspNetCore.Http;
+
 [assembly: Microsoft.AspNetCore.Mvc.ApiConventionType(typeof(Microsoft.AspNetCore.Mvc.DefaultApiConventions))]
 
 namespace TestApp._OUTPUT_
@@ -17,9 +18,9 @@ namespace TestApp._OUTPUT_
 {
     public class CodeFixAddsFullyQualifiedProducesResponseType : BaseController
     {
-        [Microsoft.AspNetCore.Mvc.ProducesResponseType(202)]
+        [Microsoft.AspNetCore.Mvc.ProducesResponseType(StatusCodes.Status202Accepted)]
-        [Microsoft.AspNetCore.Mvc.ProducesResponseType(400)]
+        [Microsoft.AspNetCore.Mvc.ProducesResponseType(StatusCodes.Status400BadRequest)]
-        [Microsoft.AspNetCore.Mvc.ProducesResponseType(404)]
+        [Microsoft.AspNetCore.Mvc.ProducesResponseType(StatusCodes.Status404NotFound)]
         [Microsoft.AspNetCore.Mvc.ProducesDefaultResponseType]
         public object GetItem(int id)
         {

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsMissingStatusCodes.Input.cs

@@ -1,10 +1,12 @@
-namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._INPUT_
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._INPUT_
 {
     [ApiController]
     [Route("[controller]/[action]")]
     public class CodeFixAddsMissingStatusCodes : ControllerBase
     {
-        [ProducesResponseType(404)]
+        [ProducesResponseType(StatusCodes.Status404NotFound)]
         public IActionResult GetItem(int id)
         {
             if (id == 0)

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsMissingStatusCodes.Output.cs

@@ -1,12 +1,14 @@
-namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
 {
     [ApiController]
     [Route("[controller]/[action]")]
     public class CodeFixAddsMissingStatusCodes : ControllerBase
     {
-        [ProducesResponseType(404)]
+        [ProducesResponseType(StatusCodes.Status404NotFound)]
-        [ProducesResponseType(200)]
+        [ProducesResponseType(StatusCodes.Status200OK)]
-        [ProducesResponseType(400)]
+        [ProducesResponseType(StatusCodes.Status400BadRequest)]
         [ProducesDefaultResponseType]
         public IActionResult GetItem(int id)
         {

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsStatusCodes.Output.cs

@@ -1,11 +1,13 @@
-namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
 {
     [ApiController]
     [Route("[controller]/[action]")]
     public class CodeFixAddsStatusCodesController : ControllerBase
     {
-        [ProducesResponseType(200)]
+        [ProducesResponseType(StatusCodes.Status200OK)]
-        [ProducesResponseType(404)]
+        [ProducesResponseType(StatusCodes.Status404NotFound)]
         [ProducesDefaultResponseType]
         public IActionResult GetItem(int id)
         {

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixAddsSuccessStatusCode.Output.cs

@@ -1,4 +1,5 @@
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Http;
 
 [assembly: ApiConventionType(typeof(DefaultApiConventions))]
 
@@ -8,9 +9,9 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
     [Route("[controller]/[action]")]
     public class CodeFixAddsSuccessStatusCode : ControllerBase
     {
-        [ProducesResponseType(201)]
+        [ProducesResponseType(StatusCodes.Status201Created)]
-        [ProducesResponseType(400)]
+        [ProducesResponseType(StatusCodes.Status400BadRequest)]
-        [ProducesResponseType(404)]
+        [ProducesResponseType(StatusCodes.Status404NotFound)]
         [ProducesDefaultResponseType]
         public ActionResult<object> GetItem(string id)
         {

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixWithConventionAddsMissingStatusCodes.Output.cs

@@ -1,4 +1,5 @@
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Http;
 
 [assembly: ApiConventionType(typeof(DefaultApiConventions))]
 
@@ -8,8 +9,8 @@ namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
     [Route("[controller]/[action]")]
     public class CodeFixWithConventionAddsMissingStatusCodes : ControllerBase
     {
-        [ProducesResponseType(202)]
+        [ProducesResponseType(StatusCodes.Status202Accepted)]
-        [ProducesResponseType(404)]
+        [ProducesResponseType(StatusCodes.Status404NotFound)]
         [ProducesDefaultResponseType]
         public ActionResult<string> GetItem(int id)
         {

test/Mvc.Api.Analyzers.Test/TestFiles/AddResponseTypeAttributeCodeFixProviderIntegrationTest/CodeFixWithConventionMethodAddsMissingStatusCodes.Output.cs

@@ -1,11 +1,13 @@
-namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Api.Analyzers._OUTPUT_
 {
     [ApiController]
     [Route("[controller]/[action]")]
     public class CodeFixWithConventionMethodAddsMissingStatusCodes : ControllerBase
     {
-        [ProducesResponseType(202)]
+        [ProducesResponseType(StatusCodes.Status202Accepted)]
-        [ProducesResponseType(404)]
+        [ProducesResponseType(StatusCodes.Status404NotFound)]
         [ProducesDefaultResponseType]
         public ActionResult<string> GetItem(int id)
         {