New overloads and changes to underlying collections. (#33)

src/LightResults/Common/IActionableResult.cs

@@ -28,7 +28,7 @@ public interface IActionableResult<out TResult> : IResult
     /// <param name="errorMessage">The error message associated with the failure.</param>
     /// <param name="metadata">The metadata associated with the failure.</param>
     /// <returns>A new instance of <typeparamref name="TResult" /> representing a failed result with the specified error message and metadata.</returns>
-    static abstract TResult Fail(string errorMessage, IDictionary<string, object> metadata);
+    static abstract TResult Fail(string errorMessage, IReadOnlyDictionary<string, object> metadata);
 
     /// <summary>Creates a failed result with the given error.</summary>
     /// <param name="error">The error associated with the failure.</param>
@@ -39,6 +39,11 @@ public interface IActionableResult<out TResult> : IResult
     /// <param name="errors">A collection of errors associated with the failure.</param>
     /// <returns>A new instance of <typeparamref name="TResult" /> representing a failed result with the specified errors.</returns>
     static abstract TResult Fail(IEnumerable<IError> errors);
+
+    /// <summary>Creates a failed result with the given errors.</summary>
+    /// <param name="errors">A collection of errors associated with the failure.</param>
+    /// <returns>A new instance of <typeparamref name="TResult" /> representing a failed result with the specified errors.</returns>
+    static abstract TResult Fail(IReadOnlyList<IError> errors);
 }
 
 /// <summary>Defines an actionable result.</summary>
@@ -69,7 +74,7 @@ public interface IActionableResult<TValue, out TResult> : IResult<TValue>
     /// <param name="errorMessage">The error message associated with the failure.</param>
     /// <param name="metadata">The metadata associated with the failure.</param>
     /// <returns>A new instance of <typeparamref name="TResult" /> representing a failed result with the specified error message and metadata.</returns>
-    static abstract TResult Fail(string errorMessage, IDictionary<string, object> metadata);
+    static abstract TResult Fail(string errorMessage, IReadOnlyDictionary<string, object> metadata);
 
     /// <summary>Creates a failed result with the given error.</summary>
     /// <param name="error">The error associated with the failure.</param>
@@ -80,5 +85,10 @@ public interface IActionableResult<TValue, out TResult> : IResult<TValue>
     /// <param name="errors">A collection of errors associated with the failure.</param>
     /// <returns>A new instance of <typeparamref name="TResult" /> representing a failed result with the specified errors.</returns>
     static abstract TResult Fail(IEnumerable<IError> errors);
+
+    /// <summary>Creates a failed result with the given errors.</summary>
+    /// <param name="errors">A collection of errors associated with the failure.</param>
+    /// <returns>A new instance of <typeparamref name="TResult" /> representing a failed result with the specified errors.</returns>
+    static abstract TResult Fail(IReadOnlyList<IError> errors);
 }
 #endif

src/LightResults/Error.cs

@@ -1,31 +1,11 @@
-using System.Collections.Immutable;
-using LightResults.Common;
-#if NET8_0_OR_GREATER
-using System.Collections.Frozen;
-#endif
+using LightResults.Common;
 
 namespace LightResults;
 
 /// <summary>Represents an error with a message and associated metadata.</summary>
 public class Error : IError
 {
-    /// <summary>Gets an empty error.</summary>
-    public static IError Empty { get; } = new Error();
-
-    internal static IReadOnlyCollection<IError> EmptyCollection { get; } = ImmutableArray<IError>.Empty;
-    internal static IReadOnlyCollection<IError> DefaultCollection { get; } = ImmutableArray.Create(Empty);
-
-    /// <inheritdoc/>
-    public string Message { get; }
-
-    /// <inheritdoc/>
-    public IReadOnlyDictionary<string, object> Metadata => _metadata;
-
-#if NET8_0_OR_GREATER
-    private readonly FrozenDictionary<string, object> _metadata;
-#else
-    private readonly ImmutableDictionary<string, object> _metadata;
-#endif
+    private static readonly IReadOnlyDictionary<string, object> EmptyMetaData = new Dictionary<string, object>();
 
     /// <summary>Initializes a new instance of the <see cref="Error"/> class.</summary>
     public Error()
@@ -38,11 +18,7 @@ public Error()
     public Error(string message)
     {
         Message = message;
-#if NET8_0_OR_GREATER
-        _metadata = FrozenDictionary<string, object>.Empty;
-#else
-        _metadata = ImmutableDictionary<string, object>.Empty;
-#endif
+        Metadata = EmptyMetaData;
     }
 
     /// <summary>Initializes a new instance of the <see cref="Error"/> class with the specified metadata.</summary>
@@ -58,40 +34,45 @@ public Error((string Key, object Value) metadata)
     public Error(string message, (string Key, object Value) metadata)
     {
         Message = message;
-#if NET8_0_OR_GREATER
-        var dictionary = new Dictionary<string, object> { { metadata.Key, metadata.Value } };
-        _metadata = dictionary.ToFrozenDictionary();
-#else
-        var builder = ImmutableDictionary.CreateBuilder<string, object>();
-        builder.Add(metadata.Key, metadata.Value);
-        _metadata = builder.ToImmutable();
-#endif
+        Metadata = new Dictionary<string, object>(1)
+        {
+            { metadata.Key, metadata.Value },
+        };
     }
 
     /// <summary>Initializes a new instance of the <see cref="Error"/> class with the specified metadata.</summary>
     /// <param name="metadata">The metadata associated with the error.</param>
-    public Error(IDictionary<string, object> metadata)
+    public Error(IReadOnlyDictionary<string, object> metadata)
         : this("", metadata)
     {
     }
 
     /// <summary>Initializes a new instance of the <see cref="Error"/> class with the specified error message and metadata.</summary>
     /// <param name="message">The error message.</param>
     /// <param name="metadata">The metadata associated with the error.</param>
-    public Error(string message, IDictionary<string, object> metadata)
+    public Error(string message, IReadOnlyDictionary<string, object> metadata)
     {
         Message = message;
-#if NET8_0_OR_GREATER
-        _metadata = metadata.ToFrozenDictionary();
-#else
-        _metadata = metadata.ToImmutableDictionary();
-#endif
+        Metadata = metadata;
     }
 
+    /// <summary>Gets an empty error.</summary>
+    public static IError Empty { get; } = new Error();
+
+    internal static IReadOnlyList<IError> EmptyErrorList { get; } = [];
+    internal static IReadOnlyList<IError> DefaultErrorList { get; } = [Empty];
+
+    /// <inheritdoc/>
+    public string Message { get; }
+
+    /// <inheritdoc/>
+    public IReadOnlyDictionary<string, object> Metadata { get; }
+
     /// <inheritdoc/>
     public override string ToString()
     {
-        var errorType = GetType().Name;
+        var errorType = GetType()
+            .Name;
 
         if (Message.Length == 0)
             return errorType;

src/LightResults/IResult.cs

@@ -7,7 +7,7 @@ public interface IResult
 {
     /// <summary>Gets a collection of errors associated with the result.</summary>
     /// <returns>An <see cref="IReadOnlyCollection{T}"/> of <see cref="IError"/> representing the errors.</returns>
-    IReadOnlyCollection<IError> Errors { get; }
+    IReadOnlyList<IError> Errors { get; }
 
     /// <summary>Gets whether the result was successful or not.</summary>
     /// <returns><c>true</c> if the result was successful; otherwise, <c>false</c>.</returns>

src/LightResults/LightResults.csproj

@@ -27,7 +27,7 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="SonarAnalyzer.CSharp" Version="9.27.0.93347">
+        <PackageReference Include="SonarAnalyzer.CSharp" Version="9.28.0.94264">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
@@ -37,7 +37,7 @@
     <!-- Output -->
     <PropertyGroup>
         <AssemblyName>LightResults</AssemblyName>
-        <Version>9.0.0-preview.11</Version>
+        <Version>9.0.0-preview.12</Version>
         <AssemblyVersion>9.0.0.0</AssemblyVersion>
         <FileVersion>9.0.0.0</FileVersion>
         <NeutralLanguage>en-US</NeutralLanguage>
@@ -120,7 +120,7 @@
         <Compile Update="Result`1.Ok.cs">
             <DependentUpon>Result`1.cs</DependentUpon>
         </Compile>
-        <Compile Update="Result`1.AsFailed.cs">
+        <Compile Update="Result`1.ToFailed.cs">
             <DependentUpon>Result`1.cs</DependentUpon>
         </Compile>
         <Compile Update="Result`1.ToString.cs">

src/LightResults/MigrationNotes.md

@@ -4,3 +4,5 @@ IsFailed property => IsFailed method
 Error property => gone
 Result<TValue>.Ok() and Result<TValue>.Fail() methods => gone
 IsIActionableResult still worth it?
+Changes to Errors Interface
+Changes to Metadata method overloads

src/LightResults/Result.Equality.cs

@@ -7,7 +7,7 @@ partial struct Result
     /// <returns><c>true</c> if the specified <see cref="Result"/> is equal to this instance; otherwise, <c>false</c>.</returns>
     public bool Equals(Result other)
     {
-        return Nullable.Equals(_errors, other._errors);
+        return Equals(_errors, other._errors);
     }
 
     /// <summary>Determines whether the specified object is equal to this instance.</summary>
@@ -22,7 +22,7 @@ public override bool Equals(object? obj)
     /// <returns>A 32-bit signed integer hash code.</returns>
     public override int GetHashCode()
     {
-        return _errors.GetHashCode();
+        return _errors?.GetHashCode() ?? 0;
     }
 
     /// <summary>Determines whether two <see cref="Result"/> instances are equal.</summary>

src/LightResults/Result.Errors.cs

@@ -5,17 +5,17 @@ namespace LightResults;
 partial struct Result
 {
     /// <inheritdoc/>
-    public IReadOnlyCollection<IError> Errors
+    public IReadOnlyList<IError> Errors
     {
         get
         {
-            if (_errors.HasValue)
+            if (_errors is not null)
                 return _errors;
 
             if (_isSuccess)
-                return Error.EmptyCollection;
+                return Error.EmptyErrorList;
 
-            return Error.DefaultCollection;
+            return Error.DefaultErrorList;
         }
     }
 
@@ -26,18 +26,16 @@ public bool HasError<TError>()
         if (_isSuccess)
             return false;
 
-        if (_errors.HasValue)
-        {
+        if (_errors is not null)
             // Do not convert to LINQ, this creates unnecessary heap allocations.
             // For is the most efficient way to loop. It is the fastest and does not allocate.
             // ReSharper disable once ForCanBeConvertedToForeach
             // ReSharper disable once LoopCanBeConvertedToQuery
-            for (var index = 0; index < _errors.Value.Length; index++)
+            for (var index = 0; index < _errors.Count; index++)
             {
-                if (_errors.Value[index] is TError)
+                if (_errors[index] is TError)
                     return true;
             }
-        }
 
         return typeof(TError) == typeof(Error);
     }
@@ -52,21 +50,19 @@ public bool HasError<TError>([MaybeNullWhen(false)] out TError error)
             return false;
         }
 
-        if (_errors.HasValue)
-        {
+        if (_errors is not null)
             // Do not convert to LINQ, this creates unnecessary heap allocations.
             // For is the most efficient way to loop. It is the fastest and does not allocate.
             // ReSharper disable once ForCanBeConvertedToForeach
             // ReSharper disable once LoopCanBeConvertedToQuery
-            for (var index = 0; index < _errors.Value.Length; index++)
+            for (var index = 0; index < _errors.Count; index++)
             {
-                if (_errors.Value[index] is not TError)
+                if (_errors[index] is not TError tError)
                     continue;
 
-                error = (TError)_errors.Value[index];
+                error = tError;
                 return true;
             }
-        }
 
         if (typeof(TError) == typeof(Error))
         {

src/LightResults/Result.Fail.cs

@@ -34,7 +34,7 @@ public static Result Fail(string errorMessage, (string Key, object Value) metada
     /// <param name="metadata">The metadata associated with the failure.</param>
     /// <param name="errorMessage">The error message associated with the failure.</param>
     /// <returns>A new instance of <see cref="Result"/> representing a failed result with the specified error message and metadata.</returns>
-    public static Result Fail(string errorMessage, IDictionary<string, object> metadata)
+    public static Result Fail(string errorMessage, IReadOnlyDictionary<string, object> metadata)
     {
         var error = new Error(errorMessage, metadata);
         return new Result(error);
@@ -55,4 +55,12 @@ public static Result Fail(IEnumerable<IError> errors)
     {
         return new Result(errors);
     }
+
+    /// <summary>Creates a failed result with the given errors.</summary>
+    /// <param name="errors">A collection of errors associated with the failure.</param>
+    /// <returns>A new instance of <see cref="Result"/> representing a failed result with the specified errors.</returns>
+    public static Result Fail(IReadOnlyList<IError> errors)
+    {
+        return new Result(errors);
+    }
 }

src/LightResults/Result.Fail`1.cs

@@ -36,7 +36,7 @@ public static Result<TValue> Fail<TValue>(string errorMessage, (string Key, obje
     /// <param name="metadata">The metadata associated with the failure.</param>
     /// <typeparam name="TValue">The type of the value of the result.</typeparam>
     /// <returns>A new instance of <see cref="Result{TValue}"/> representing a failed result with the specified error message and metadata.</returns>
-    public static Result<TValue> Fail<TValue>(string errorMessage, IDictionary<string, object> metadata)
+    public static Result<TValue> Fail<TValue>(string errorMessage, IReadOnlyDictionary<string, object> metadata)
     {
         var error = new Error(errorMessage, metadata);
         return new Result<TValue>(error);
@@ -59,4 +59,13 @@ public static Result<TValue> Fail<TValue>(IEnumerable<IError> errors)
     {
         return new Result<TValue>(errors);
     }
+
+    /// <summary>Creates a failed result with the given errors.</summary>
+    /// <param name="errors">A collection of errors associated with the failure.</param>
+    /// <typeparam name="TValue">The type of the value of the result.</typeparam>
+    /// <returns>A new instance of <see cref="Result{TValue}"/> representing a failed result with the specified errors.</returns>
+    public static Result<TValue> Fail<TValue>(IReadOnlyList<IError> errors)
+    {
+        return new Result<TValue>(errors);
+    }
 }

src/LightResults/Result.IsFailed.cs

@@ -15,8 +15,8 @@ public bool IsFailed([MaybeNullWhen(false)] out IError error)
     {
         if (_isSuccess)
             error = default;
-        else if (_errors.HasValue)
-            error = _errors.Value[0];
+        else if (_errors is not null)
+            error = _errors[0];
         else
             error = Error.Empty;
 

src/LightResults/Result.ToString.cs

@@ -10,8 +10,8 @@ public override string ToString()
         if (_isSuccess)
             return $"{nameof(Result)} {{ IsSuccess = True }}";
 
-        if (_errors.HasValue && _errors.Value[0].Message.Length > 0)
-            return StringHelper.GetResultErrorString(_errors.Value[0].Message);
+        if (_errors is not null && _errors[0].Message.Length > 0)
+            return StringHelper.GetResultErrorString(_errors[0].Message);
 
         return $"{nameof(Result)} {{ IsSuccess = False }}";
     }

src/LightResults/Result.cs

@@ -1,4 +1,3 @@
-using System.Collections.Immutable;
 #if NET7_0_OR_GREATER
 using LightResults.Common;
 #endif
@@ -14,7 +13,7 @@ namespace LightResults;
 #endif
 {
     private readonly bool _isSuccess = false;
-    private readonly ImmutableArray<IError>? _errors;
+    private readonly IReadOnlyList<IError>? _errors;
 
     private Result(bool isSuccess)
     {
@@ -23,16 +22,16 @@ private Result(bool isSuccess)
 
     private Result(IError error)
     {
-        _errors = ImmutableArray.Create(error);
+        _errors = [error];
     }
 
-    internal Result(ImmutableArray<IError> errors)
+    private Result(IEnumerable<IError> errors)
     {
-        _errors = errors;
+        _errors = errors.ToArray();
     }
 
-    private Result(IEnumerable<IError> errors)
+    internal Result(IReadOnlyList<IError> errors)
     {
-        _errors = errors.ToImmutableArray();
+        _errors = errors;
     }
 }