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Merged
merged 4 commits into from
Mar 13, 2025
Merged

Akka.Util: improve Result<T> #7520

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8ed734e
`Result<T>`: test equality members
Aaronontheweb Mar 13, 2025
23d1769
make `Result<T>` nullable
Aaronontheweb Mar 13, 2025
8f8f5e7
reverted back to using fields
Aaronontheweb Mar 13, 2025
e3ae885
reverted back to using fields
Aaronontheweb Mar 13, 2025
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37 changes: 24 additions & 13 deletions src/core/Akka.API.Tests/verify/CoreAPISpec.ApproveCore.DotNet.verified.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -5494,26 +5494,37 @@ namespace Akka.Util
public static Akka.Util.Option<T> op_Implicit(T value) { }
public static bool !=(Akka.Util.Option<T> left, Akka.Util.Option<T> right) { }
}
[System.Runtime.CompilerServices.NullableAttribute(0)]
public class static Result
{
public static Akka.Util.Result<T> Failure<T>(System.Exception exception) { }
public static Akka.Util.Result<T> From<T>(System.Func<T> func) { }
public static Akka.Util.Result<T> FromTask<T>(System.Threading.Tasks.Task<T> task) { }
public static Akka.Util.Result<T> Success<T>(T value) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
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API change - make fields into nullable properties.

0,
1})]
public static Akka.Util.Result<T> Failure<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(System.Exception exception) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
0,
1})]
public static Akka.Util.Result<T> From<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(System.Func<T> func) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
0,
1})]
public static Akka.Util.Result<T> FromTask<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(System.Threading.Tasks.Task<T> task) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
0,
1})]
public static Akka.Util.Result<T> Success<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(T value) { }
}
public struct Result<T> : System.IEquatable<Akka.Util.Result<T>>
[System.Runtime.CompilerServices.IsReadOnlyAttribute()]
public struct Result<[System.Runtime.CompilerServices.NullableAttribute(2)] T> : System.IEquatable<Akka.Util.Result<T>>
{
public readonly System.Exception Exception;
public readonly bool IsSuccess;
public readonly T Value;
public Result(T value) { }
public Result(System.Exception exception) { }
public bool Equals(Akka.Util.Result<T> other) { }
public override bool Equals(object obj) { }
public override int GetHashCode() { }
[System.Runtime.CompilerServices.NullableAttribute(2)]
public System.Exception Exception { get; }
public bool IsSuccess { get; }
[System.Runtime.CompilerServices.NullableAttribute(2)]
public T Value { get; }
public override string ToString() { }
public static bool ==(Akka.Util.Result<T> left, Akka.Util.Result<T> right) { }
public static bool !=(Akka.Util.Result<T> left, Akka.Util.Result<T> right) { }
}
public class Right<T>
{
Expand Down
36 changes: 23 additions & 13 deletions src/core/Akka.API.Tests/verify/CoreAPISpec.ApproveCore.Net.verified.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -5483,26 +5483,36 @@ namespace Akka.Util
public static Akka.Util.Option<T> op_Implicit(T value) { }
public static bool !=(Akka.Util.Option<T> left, Akka.Util.Option<T> right) { }
}
[System.Runtime.CompilerServices.NullableAttribute(0)]
public class static Result
{
public static Akka.Util.Result<T> Failure<T>(System.Exception exception) { }
public static Akka.Util.Result<T> From<T>(System.Func<T> func) { }
public static Akka.Util.Result<T> FromTask<T>(System.Threading.Tasks.Task<T> task) { }
public static Akka.Util.Result<T> Success<T>(T value) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
0,
1})]
public static Akka.Util.Result<T> Failure<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(System.Exception exception) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
0,
1})]
public static Akka.Util.Result<T> From<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(System.Func<T> func) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
0,
1})]
public static Akka.Util.Result<T> FromTask<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(System.Threading.Tasks.Task<T> task) { }
[return: System.Runtime.CompilerServices.NullableAttribute(new byte[] {
0,
1})]
public static Akka.Util.Result<T> Success<[System.Runtime.CompilerServices.NullableAttribute(2)] T>(T value) { }
}
public struct Result<T> : System.IEquatable<Akka.Util.Result<T>>
public struct Result<[System.Runtime.CompilerServices.NullableAttribute(2)] T> : System.IEquatable<Akka.Util.Result<T>>
{
public readonly System.Exception Exception;
public readonly bool IsSuccess;
public readonly T Value;
public Result(T value) { }
public Result(System.Exception exception) { }
public bool Equals(Akka.Util.Result<T> other) { }
public override bool Equals(object obj) { }
public override int GetHashCode() { }
[System.Runtime.CompilerServices.NullableAttribute(2)]
public System.Exception Exception { get; }
public bool IsSuccess { get; }
[System.Runtime.CompilerServices.NullableAttribute(2)]
public T Value { get; }
public override string ToString() { }
public static bool ==(Akka.Util.Result<T> left, Akka.Util.Result<T> right) { }
public static bool !=(Akka.Util.Result<T> left, Akka.Util.Result<T> right) { }
}
public class Right<T>
{
Expand Down
21 changes: 21 additions & 0 deletions src/core/Akka.Tests/Util/ResultSpec.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -118,6 +118,27 @@ public void IncompleteTaskResult()
.Should().Throw<ArgumentException>().WithMessage("Task is not completed.*");
}

[Fact]
public void ResultEqualitySpec()
{
var result1 = Result.Success(1);
var result2 = Result.Success(1);
var exception = new TestException("BOOM"); // equality by value does not work for exceptions
var result3 = Result.Failure<int>(exception);
var result4 = Result.Failure<int>(exception);
var result5 = Result.Success("foo");
var result6 = Result.Success("bar");
var result51 = Result.Success("foo");

result1.Equals(result2).Should().BeTrue();
result1.Equals(result3).Should().BeFalse();
result3.Equals(result4).Should().BeTrue();
result5.Equals(result51).Should().BeTrue();
(result5 == result51).Should().BeTrue(); // test operator overloads
(result5 == result6).Should().BeFalse(); // test operator overloads
(result5 != result6).Should().BeTrue(); // test operator overloads
}

private static Task<int> CompletedTask(int n)
{
var tcs = new TaskCompletionSource<int>();
Expand Down
116 changes: 18 additions & 98 deletions src/core/Akka/Util/Result.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,37 +7,30 @@

using System;
using System.Threading.Tasks;
#nullable enable

namespace Akka.Util
{
//A generic type can't have a explicit layout
//[StructLayout(LayoutKind.Explicit)]
/// <summary>
/// TBD
/// A result type frequently used inside Akka.Streams and elsewhere.
/// </summary>
/// <typeparam name="T">TBD</typeparam>
public struct Result<T> : IEquatable<Result<T>>
public readonly record struct Result<T>
{
//[FieldOffset(0)]
/// <summary>
/// TBD
/// </summary>
public readonly bool IsSuccess;
//[FieldOffset(1)]
/// <summary>
/// TBD
/// <c>true</c> if the result is successful, <c>false</c> otherwise.
/// </summary>
public readonly T Value;
//[FieldOffset(1)]
public bool IsSuccess { get; }

/// <summary>
/// TBD
/// <c>null</c> when <see cref="IsSuccess"/> is <c>false</c>.
/// </summary>
public readonly Exception Exception;

public T? Value { get; }
/// <summary>
/// TBD
/// <c>null</c> when <see cref="IsSuccess"/> is <c>true</c>.
/// </summary>
/// <param name="value">TBD</param>
public Exception? Exception { get; }

public Result(T value) : this()
{
IsSuccess = true;
Expand All @@ -52,89 +45,25 @@ public Result(Exception exception) : this()
IsSuccess = false;
Exception = exception;
}


public bool Equals(Result<T> other)
{
if (IsSuccess ^ other.IsSuccess) return false;
return IsSuccess
? Equals(Value, other.Value)
: Equals(Exception, other.Exception);
}


public override bool Equals(object obj)
{
if (obj is Result<T> result) return Equals(result);
return false;
}


public override int GetHashCode()
{
return IsSuccess
? (Value == null ? 0 : Value.GetHashCode())
: (Exception == null ? 0 : Exception.GetHashCode());
}

/// <summary>
/// Compares two specified <see cref="Result{T}"/> for equality.
/// </summary>
/// <param name="left">The first <see cref="Result{T}"/> used for comparison</param>
/// <param name="right">The second <see cref="Result{T}"/> used for comparison</param>
/// <returns><c>true</c> if both <see cref="Result{T}"/> are equal; otherwise <c>false</c></returns>
public static bool operator ==(Result<T> left, Result<T> right)
{
return left.Equals(right);
}

/// <summary>
/// Compares two specified <see cref="Result{T}"/> for inequality.
/// </summary>
/// <param name="left">The first <see cref="Result{T}"/> used for comparison</param>
/// <param name="right">The second <see cref="Result{T}"/> used for comparison</param>
/// <returns><c>true</c> if both <see cref="Result{T}"/> are not equal; otherwise <c>false</c></returns>
public static bool operator !=(Result<T> left, Result<T> right)
{
return !(left == right);
}

public override string ToString() => IsSuccess ? $"Success ({Value})" : $"Failure ({Exception})";
}

/// <summary>
/// TBD
/// Helper methods for creating <see cref="Result{T}"/> instances.
/// </summary>
public static class Result
{
/// <summary>
/// TBD
/// </summary>
/// <typeparam name="T">TBD</typeparam>
/// <param name="value">TBD</param>
/// <returns>TBD</returns>
public static Result<T> Success<T>(T value)
{
return new Result<T>(value);
}

/// <summary>
/// TBD
/// </summary>
/// <typeparam name="T">TBD</typeparam>
/// <param name="exception">TBD</param>
/// <returns>TBD</returns>

public static Result<T> Failure<T>(Exception exception)
{
return new Result<T>(exception);
}

/// <summary>
/// TBD
/// </summary>
/// <typeparam name="T">TBD</typeparam>
/// <param name="task">TBD</param>
/// <returns>TBD</returns>

public static Result<T> FromTask<T>(Task<T> task)
{
if(!task.IsCompleted)
Expand All @@ -143,7 +72,7 @@ public static Result<T> FromTask<T>(Task<T> task)
if(task.Exception is not null)
return new Result<T>(task.Exception);

if (task.IsCanceled && task.Exception is null)
if (task is { IsCanceled: true, Exception: null })
{
try
{
Expand All @@ -157,18 +86,12 @@ public static Result<T> FromTask<T>(Task<T> task)
throw new InvalidOperationException("Should never reach this line!");
}

if(task.IsFaulted && task.Exception is null)
if(task is { IsFaulted: true, Exception: null })
throw new InvalidOperationException("Should never happen! something is wrong with .NET Task code!");

return new Result<T>(task.Result);
}

/// <summary>
/// TBD
/// </summary>
/// <typeparam name="T">TBD</typeparam>
/// <param name="func">TBD</param>
/// <returns>TBD</returns>

public static Result<T> From<T>(Func<T> func)
{
try
Expand All @@ -181,8 +104,5 @@ public static Result<T> From<T>(Func<T> func)
return new Result<T>(e);
}
}



}
}
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