rspec/rules/S4027/csharp/rule.adoc

== Why is this an issue?

Exceptions types should provide the following constructors:

* `public MyException()`
* `public MyException(string)`
* `public MyException(string, Exception)`

The absence of these constructors can complicate exception handling and limit the information that can be provided when an exception is thrown.

== How to fix it

=== Code examples

==== Noncompliant code example

[source,csharp,diff-id=1,diff-type=noncompliant]
----
public class MyException : Exception // Noncompliant: several constructors are missing
{
    public MyException()
    {
    }
}
----

==== Compliant solution

[source,csharp,diff-id=1,diff-type=compliant]
----
public class MyException : Exception
{
    public MyException()
    {
    }

    public MyException(string message)
        : base(message)
    {
    }

    public MyException(string message, Exception innerException)
        : base(message, innerException)
    {
    }
}
----

== Resources

=== Documentation

* Microsoft Learn: https://learn.microsoft.com/en-us/dotnet/standard/exceptions/how-to-create-user-defined-exceptions[How to create user-defined exceptions]
* Microsoft Learn: https://learn.microsoft.com/en-us/dotnet/api/system.exception[Exception Class]
* Microsoft Learn: https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals/exceptions/creating-and-throwing-exceptions#define-exception-classes[Define exception classes]

include::./rspecator.adoc[]