Fix S2589 FP: List count with AddRange()

[rodchenkov]

Description

I have warning S2589 for list.Count == 0 but I'm sure it is false positive.

Repro steps

Please find code below:

        public void Apply(OpenApiOperation operation, OperationFilterContext context)
        {
            ArgumentNullException.ThrowIfNull(operation);
            ArgumentNullException.ThrowIfNull(context);

            if (Array.Exists(context.MethodInfo.GetCustomAttributes(true), x => x is AllowAnonymousAttribute)) return;

            var authorizeAttributes = new List<AuthorizeAttribute>();
            var swaggerSecurityAttributes = new List<SwaggerSecurityAttribute>();

            // Get method attributes
            authorizeAttributes.AddRange(context.MethodInfo.GetCustomAttributes(true).OfType<AuthorizeAttribute>());
            swaggerSecurityAttributes.AddRange(context.MethodInfo.GetCustomAttributes(true).OfType<SwaggerSecurityAttribute>());

            // Get class attributes
            if (context.MethodInfo.DeclaringType != null)
            {
                authorizeAttributes.AddRange(context.MethodInfo.DeclaringType.GetCustomAttributes(true).OfType<AuthorizeAttribute>());
                swaggerSecurityAttributes.AddRange(context.MethodInfo.DeclaringType.GetCustomAttributes(true).OfType<SwaggerSecurityAttribute>());
            }

#pragma warning disable S2589
            if (authorizeAttributes.Count == 0) return;
#pragma warning restore S2589

            ...

         }

Expected behavior

No warning S2589 for line if (authorizeAttributes.Count == 0) return;

Actual behavior

Warning S2589 for line if (authorizeAttributes.Count == 0) return;

Known workarounds

Only suppress warning

Related information

• C#
• Visual Studio 2022
• dotnet 6/7/8
• SonarScanner for .NET version 9.16.0.82469
• Linux

[gregory-paidis-sonarsource]

Hey @rodchenkov , I confirm that this is a false positive. I added it to our backlog, where it will be taken care of along other S2589 FPs soon. Thanks for raising this.

[gregory-paidis-sonarsource]

Something to add, implementation-wise: In the expression first.AddRange(second), second is cleared of CollectionConstraint because it's used as Argument. This might be problematic when trying to establish when AddRange should influence the CollectionConstraint of first.

[devedse]

I also ran into this issue, wouldn't it be better to disable this rule for now until it's fixed?

Here's another simple scenario to reproduce it:

namespace SonarQubeRulesTest;

internal class Program
{
    static void Main(string[] args)
    {
        var theList = new List<int>();

        theList.AddRange(GetNumbers());

        if (theList.Any())
        {
            Console.WriteLine("Numbers found");
        }
        else
        {
            Console.WriteLine("No numbers found");
        }

    }

    public static IEnumerable<int> GetNumbers()
    {
        return new List<int> { };
    }
}

[Tim-Pohlmann]

Another user report