Fix AD0001 in S138: NullReferenceException

[Tim-Pohlmann]

Description

The error appears in the project JellyFin, which I recently added to peachee-dotnet.

CSC : error AD0001: Analyzer 'SonarAnalyzer.Rules.CSharp.MethodsShouldNotHaveTooManyLines' threw an exception of type 'System.NullReferenceException' with message 'Object reference not set to an instance of an object.'. [C:\Project\Jellyfin.Server\Jellyfin.Server.csproj]

Repro steps

JellyFin GitHub: https://github.com/jellyfin/jellyfin
Error Log: https://cirrus-ci.com/task/4552322081095680?logs=build#L2576
Peach configuration: https://github.com/SonarSource/peachee-dotnet/blob/b8a849c086699dfb1ec9340a26eaef1ac1e636b6/.cirrus.yml#L258-L259

Related information

• .NET 6

[antonioaversa]

The exception is produced in

private static IEnumerable<SyntaxToken> GetMethodTokens(LocalFunctionStatementSyntaxWrapper wrapper) =>
    wrapper.ExpressionBody?.Expression.DescendantTokens()
    ?? wrapper.Body.Statements.SelectMany(s => s.DescendantTokens());

Due to Body being null, in presence of extern local functions, which don't have body.

#pragma warning disable SA1300 // Entrypoint is case sensitive.
[DllImport("libc")]
static extern int chmod(string pathname, int mode);
#pragma warning restore SA1300

Example in .\Jellyfin.Server\Program.cs.