Rule S3887: Mutable, non-private fields should not be "readonly" (Bug warning) is not caught by sonar scanner and it is not displayed in the report on SonarQube 8.2 version community edition

SonarQube
#1

I’m using SonarQube sonarqube-8.2.0.32929 community edition, sonar scanner sonar-scanner-msbuild-4.7.1.2311-net46

The warning for the rule S3887: Mutable, non-private fields should not be “readonly” (Category: Bug) is not caught by sonar scanner and it is not displayed in the report.

E.g. Analyzing :

using System.Collections.Generic;
/// <title>Mutable, non-private fields should not be "readonly"</title>
/// <summary>
/// Using the readonly keyword on a field means that it can't be changed after initialization. However, when applied to collections or arrays, 
/// that's only partly true. readonly enforces that another instance can't be assigned to the field, but it cannot keep the contents from being updated. 
/// That means that in practice, the field value really can be changed, and the use of readonly on such a field is misleading, and you're likely to not be getting the behavior you expect.
/// This rule raises an issue when a non-private, readonly field is an array or collection.
/// </summary>
namespace SonarQubeToolVerification.Bug.Warnings
{
    public class S3887Warning
    {
        public readonly int[] intArr;  // Noncompliant
        public readonly LinkedList<int> intList;  // Noncompliant
    }
}

Waiting for Bug warning:

S3887: Mutable, non-private fields should not be “readonly”
but nothing displayed in the report.

Any suggestions?

#3

hi @mike1970fl03

This is by design - check this explanation from our test cases:

When the types are uninitialized, this is equivalent to being initialized to null so we don’t report

This behavior was added in #1695

When a mutable readonly field is not initialized, this is equivalent to being initialized with null . As the rule doesn’t report on the latter it should not report on uninitialized fields.

We don’t raise when a read-only collection field is initialized with null because we consider it an immutable value.