RequireAttributeUsageAttribute.cs

/*
 * SonarAnalyzer for .NET
 * Copyright (C) 2015-2024 SonarSource SA
 * mailto: contact AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

namespace SonarAnalyzer.Rules.CSharp;

[DiagnosticAnalyzer(LanguageNames.CSharp)]
public sealed class RequireAttributeUsageAttribute : SonarDiagnosticAnalyzer
{
    internal const string DiagnosticId = "S3993";
    private const string MessageFormat = "Specify AttributeUsage on '{0}'{1}.";

    private static readonly DiagnosticDescriptor rule =
        DescriptorFactory.Create(DiagnosticId, MessageFormat);

    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(rule);

    protected override void Initialize(SonarAnalysisContext context)
    {
        context.RegisterNodeAction(c =>
        {
            var classDeclaration = (ClassDeclarationSyntax)c.Node;
            var classSymbol = c.SemanticModel.GetDeclaredSymbol(classDeclaration);

            if (classSymbol == null
                || classSymbol.IsAbstract
                || !classSymbol.DerivesFrom(KnownType.System_Attribute)
                || classSymbol.HasAttribute(KnownType.System_AttributeUsageAttribute))
            {
                return;
            }

            var additionalText = InheritsAttributeUsage(classSymbol)
                ? " to improve readability, even though it inherits it from its base type"
                : string.Empty;

            c.ReportIssue(Diagnostic.Create(rule, classDeclaration.Identifier.GetLocation(),
                classSymbol.Name, additionalText));
        },
        SyntaxKind.ClassDeclaration);
    }

    private static bool InheritsAttributeUsage(INamedTypeSymbol classSymbol) =>
        classSymbol.GetSelfAndBaseTypes()
            // System.Attribute already has AttributeUsage, we don't want to report it
            .TakeWhile(t => !t.Is(KnownType.System_Attribute))
            .Any(t => t.HasAttribute(KnownType.System_AttributeUsageAttribute));
}