VALFY05: Valuify cannot guarantee Equality

Type Name	VALFY05_ValuifyAttributeAnalyzer
Diagnostic Id	VALFY05
Category	Design
Severity	Warning
Is Enabled By Default	Yes

Cause

The type inherits from a base class that has a override for Equals and/or GetHashCode that is marked with the sealed keyword, preventing Valuify from overriding the behaviors, undermining its ability to guarantee record like equality behavior.

Rule Description

A violation of this rule occurs when Valuify is applied to a type that inherits from a base class that has a override for Equals and/or GetHashCode that is marked with the sealed keyword, preventing Valuify from overriding the behaviors, undermining its ability to guarantee record like equality behavior.

For example:

public class Base
{
    public sealed override bool Equals(object obj)
        => base.Equals(obj);

    public sealed override int GetHashCode()
        => base.GetHashCode();
}

[Valuify]
public class Example
    : Base
{
    public string Property { get; set; }
}

In this example, Base has applied the sealed keyword to both Equals and GetHashCode, preventing Valuify from providing an override for Example that ensures record like equality behavior.

How to Fix Violations

Reevaluate the decision to apply the Valuify attribute. If the behavior of the sealed base methods aligns with the requirements, then this warning can be ignored, otherwise remove the Valuify attribute and apply an alternative implementation that aligns with the requirements.

When to Suppress Warnings

Warnings from this rule should be suppressed only if there the base implementation aligns with the requirements, otherwise the Valuify attribute should be removed from the containing type.

If suppression is desired, one of the following approaches can be used:

#pragma warning disable VALFY05 // Type does not utilize Valuify
[Valuify]
public class Example
    : Base
{
    public string Property { get; set; }
}
#pragma warning restore VALFY05 // Type does not utilize Valuify

or alternatively:

[SuppressMessage("Usage", "VALFY05:Valuify cannot guarantee Equality", Justification = "Explanation for suppression")]
[Valuify]
public class Example
    : Base
{
    public string Property { get; set; }
}

How to Disable VALFY05

It is not recommended to disable the rule, as this may result in some confusion if expected extension methods are not present.

# Disable VALFY05: Valuify cannot guarantee Equality
[*.cs]
dotnet_diagnostic.VALFY05.severity = none