Update Error usage to utilize ErrorList record with ErrorMessages and…

… CorrelationId (#173)

* Update Error usage to take in a strongly typed wrapper class, ErrorList, for ErrorMessages and CorrelationId

* Add default value for simpler usage of Error method

* Add XML comments

---------

Co-authored-by: Steve Smith <[email protected]>

src/Ardalis.Result/ErrorList.cs

@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace Ardalis.Result;
+
+/// <summary>
+/// A wrapper class for a list of error messages and an optional CorrelationId.
+/// </summary>
+/// <param name="ErrorMessages"></param>
+/// <param name="CorrelationId"></param>
+public record ErrorList(IEnumerable<string> ErrorMessages, string? CorrelationId);

src/Ardalis.Result/Result.Void.cs

@@ -53,28 +53,15 @@ public static Result<T> Success<T>(T value, string successMessage)
         /// Represents an error that occurred during the execution of the service.
         /// Error messages may be provided and will be exposed via the Errors property.
         /// </summary>
-        /// <param name="errorMessages">A list of string error messages.</param>
-        /// <returns>A Result</returns>
-        public new static Result Error(params string[] errorMessages)
-        {
-            return new Result(ResultStatus.Error) { Errors = errorMessages };
-        }
-
-        /// <summary>
-        /// Represents an error that occurred during the execution of the service.
-        /// Sets the CorrelationId property to the provided value
-        /// Error messages may be provided and will be exposed via the Errors property.
-        /// </summary>
-        /// <param name="correlationId">Sets the CorrelationId property.</param>
-        /// <param name="errorMessages">A list of string error messages.</param>
+        /// <param name="error">An optional instance of ErrorList with list of string error messages and CorrelationId.</param>
         /// <returns>A Result</returns>
-        public static Result ErrorWithCorrelationId(string correlationId, params string[] errorMessages)
+        public new static Result Error(ErrorList error = null)
         {
-            return new Result(ResultStatus.Error)
-            {
-                CorrelationId = correlationId,
-                Errors = errorMessages
-            };
+          return new Result(ResultStatus.Error)
+          {
+             CorrelationId = error?.CorrelationId ?? string.Empty,
+             Errors = error?.ErrorMessages ?? []
+          };
         }
 
         /// <summary>

src/Ardalis.Result/Result.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json.Serialization;
 
 namespace Ardalis.Result
@@ -133,11 +134,15 @@ public static Result<T> Created(T value, string location)
         /// Represents an error that occurred during the execution of the service.
         /// Error messages may be provided and will be exposed via the Errors property.
         /// </summary>
-        /// <param name="errorMessages">A list of string error messages.</param>
+        /// <param name="error">An optional instance of ErrorList with list of string error messages and CorrelationId.</param>
         /// <returns>A Result<typeparamref name="T"/></returns>
-        public static Result<T> Error(params string[] errorMessages)
+        public static Result<T> Error(ErrorList error = null)
         {
-            return new Result<T>(ResultStatus.Error) { Errors = errorMessages };
+            return new Result<T>(ResultStatus.Error)
+            {
+              CorrelationId = error?.CorrelationId ?? string.Empty,
+              Errors = error?.ErrorMessages ?? []
+            };
         }
 
         /// <summary>

src/Ardalis.Result/ResultExtensions.cs

@@ -28,7 +28,7 @@ public static Result<TDestination> Map<TSource, TDestination>(this Result<TSourc
                 case ResultStatus.Unauthorized: return Result<TDestination>.Unauthorized();
                 case ResultStatus.Forbidden: return Result<TDestination>.Forbidden();
                 case ResultStatus.Invalid: return Result<TDestination>.Invalid(result.ValidationErrors);
-                case ResultStatus.Error: return Result<TDestination>.Error(result.Errors.ToArray());
+                case ResultStatus.Error: return Result<TDestination>.Error(new ErrorList(result.Errors.ToArray(), result.CorrelationId));
                 case ResultStatus.Conflict: return result.Errors.Any()
                                         ? Result<TDestination>.Conflict(result.Errors.ToArray())
                                         : Result<TDestination>.Conflict();

tests/Ardalis.Result.UnitTests/PagedResultConstructor.cs

@@ -1,4 +1,5 @@
 using FluentAssertions;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using Xunit;
@@ -94,12 +95,14 @@ public void InitializesStatusToErrorGivenErrorFactoryCall()
     public void InitializesStatusToErrorAndSetsErrorMessageGivenErrorFactoryCall()
     {
         string errorMessage = "Something bad happened.";
+        string correlationId = Guid.NewGuid().ToString();
         var result = Result<object>
-            .Error(errorMessage)
+            .Error(new([errorMessage], correlationId))
             .ToPagedResult(_pagedInfo);
 
         Assert.Equal(ResultStatus.Error, result.Status);
-        Assert.Equal(errorMessage, result.Errors.First());
+        Assert.Equal(errorMessage, result.Errors.Single());
+        Assert.Equal(correlationId, result.CorrelationId);
         Assert.Equal(_pagedInfo, result.PagedInfo);
     }
 

tests/Ardalis.Result.UnitTests/ResultConstructor.cs

@@ -1,4 +1,5 @@
 using FluentAssertions;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using Xunit;
@@ -7,6 +8,10 @@ namespace Ardalis.Result.UnitTests;
 
 public class ResultConstructor
 {
+    private class TestObject
+    {
+    }
+
     [Fact]
     public void InitializesStronglyTypedStringValue()
     {
@@ -34,10 +39,6 @@ public void InitializesStronglyTypedObjectValue()
         Assert.Equal(expectedObject, result.Value);
     }
 
-    private class TestObject
-    {
-    }
-
     [Fact]
     public void InitializesValueToNullGivenNullConstructorArgument()
     {
@@ -134,10 +135,12 @@ public void InitializesStatusToErrorGivenErrorFactoryCall()
     public void InitializesStatusToErrorAndSetsErrorMessageGivenErrorFactoryCall()
     {
         string errorMessage = "Something bad happened.";
-        var result = Result<object>.Error(errorMessage);
+        string correlationId = Guid.NewGuid().ToString();
+        var result = Result<object>.Error(new([errorMessage], correlationId));
 
         Assert.Equal(ResultStatus.Error, result.Status);
-        Assert.Equal(errorMessage, result.Errors.First());
+        Assert.Equal(errorMessage, result.Errors.Single());
+      Assert.Equal(correlationId, result.CorrelationId);
     }
 
     [Fact]
@@ -232,7 +235,7 @@ public void InitializedIsSuccessTrueForSuccessFactoryCall()
     [Fact]
     public void InitializedIsSuccessFalseForErrorFactoryCall()
     {
-        var result = Result<object>.Error(null);
+        var result = Result<object>.Error();
 
         Assert.False(result.IsSuccess);
     }

tests/Ardalis.Result.UnitTests/ResultMap.cs

@@ -155,25 +155,25 @@ public void ShouldProduceInvalidWithoutValidationErrors()
         [Fact]
         public void ShouldProduceErrorResultWithErrors()
         {
-            var errors = new string[] { "Error 1", "Error 2" };
-            var result = Result<int>.Error(errors);
+            var errorList = new ErrorList(["Error 1", "Error 2"], default);
+            var result = Result<int>.Error(errorList);
 
             var actual = result.Map(val => val.ToString());
 
             actual.Status.Should().Be(ResultStatus.Error);
-            actual.Errors.Should().BeEquivalentTo(errors);
+            actual.Errors.Should().BeEquivalentTo(errorList.ErrorMessages);
         }
 
         [Fact]
         public void ShouldProduceErrorResultWithNoErrors()
         {
-            var errors = Array.Empty<string>();
-            var result = Result<int>.Error(errors);
+            var result = Result<int>.Error();
 
             var actual = result.Map(val => val.ToString());
 
             actual.Status.Should().Be(ResultStatus.Error);
-            actual.Errors.Should().BeEquivalentTo(errors);
+            actual.Errors.Should().BeEmpty();
+            actual.CorrelationId.Should().BeEmpty();
         }
 
         [Fact]

tests/Ardalis.Result.UnitTests/ResultVoidConstructor.cs

@@ -41,7 +41,7 @@ public void InitializesSuccessResultWithMessageWithFactoryMethod()
     [InlineData("test1", "test2")]
     public void InitializesErrorResultWithFactoryMethod(params string[] errors)
     {
-        var result = Result.Error(errors);
+        var result = Result.Error(new ErrorList(errors, null));
 
         Assert.Null(result.Value);
         Assert.Equal(ResultStatus.Error, result.Status);
@@ -59,7 +59,7 @@ public void InitializesErrorResultWithCorrelationIdWithFactoryMethod()
     {
         var correlationId = "testId";
         var errors = new string[] { "Error 1", "Error 2" };
-        var result = Result.ErrorWithCorrelationId(correlationId, errors);
+        var result = Result.Error(new ErrorList(errors, correlationId));
 
         Assert.Null(result.Value);
         Assert.Equal(ResultStatus.Error, result.Status);

tests/Ardalis.Result.UnitTests/ResultVoidToResultOfT.cs

@@ -11,10 +11,12 @@ public class ResultVoidToResultOfT
     [InlineData("test1", "test2")]
     public void ConvertFromErrorResultOfUnit(params string[] errors)
     {
-        var result = DoBusinessOperationExample<object>(Result.Error(errors));
+        var errorList = new ErrorList(errors, default);
+        var result = DoBusinessOperationExample<object>(Result.Error(errorList));
 
         Assert.Null(result.Value);
         Assert.Equal(ResultStatus.Error, result.Status);
+        Assert.Empty(result.CorrelationId);
 
         foreach (var error in errors)
         {