Unable to rollback mutation

Stryker fails to rollback mutations for several nodes.

Version 0.7.0 (beta)

[10:48:59 INF] Using C:\foo\bar.csproj as project file
[10:48:59 INF] Starting initial build
[10:49:04 INF] Initial build successful
[10:49:05 INF] Using testrunner DotnetTestRunner
[10:49:05 INF] Initial testrun started
[10:49:40 INF] Total number of tests found in initial test run: 0
[10:49:40 INF] Initial testrun successful in 34437 ms
[10:49:40 INF] Using 81655 ms as testrun timeout
[10:49:41 INF] 949 mutants created
[10:49:43 ERR] Unable to rollback mutation for node reader with diagnostic message Der Name "reader" ist im aktuellen Kontext nicht vorhanden.
[10:49:43 ERR] Unable to rollback mutation for node command with diagnostic message Der Name "command" ist im aktuellen Kontext nicht vorhanden.
[10:49:43 ERR] Unable to rollback mutation for node mySqlConnection with diagnostic message Der Name "mySqlConnection" ist im aktuellen Kontext nicht vorhanden.
[10:49:43 ERR] Unable to rollback mutation for node mySqlConnection with diagnostic message Der Name "mySqlConnection" ist im aktuellen Kontext nicht vorhanden.
[10:49:43 ERR] An error occurred during the mutation test run
System.ArgumentException: Der aufzuzeichnende Knoten ist kein untergeordnetes Element des Stamms.
   at Microsoft.CodeAnalysis.SyntaxNodeExtensions.TrackNodes[TRoot](TRoot root, IEnumerable`1 nodes) in /_/src/Compilers/Core/Portable/Syntax/SyntaxNodeExtensions_Tracking.cs:line 43
   at Stryker.Core.Compiling.RollbackProcess.RemoveMutantIfStatements(SyntaxTree originalTree, ICollection`1 diagnosticInfo)
   at Stryker.Core.Compiling.RollbackProcess.Start(CSharpCompilation compiler, ImmutableArray`1 diagnostics)
   at Stryker.Core.Compiling.CompilingProcess.Compile(IEnumerable`1 syntaxTrees, MemoryStream ms)
   at Stryker.Core.MutationTest.MutationTestProcess.Mutate()
   at Stryker.Core.StrykerRunner.RunMutationTest(StrykerOptions options)
[10:49:43 INF] Time Elapsed 00:00:43.7736487

We have some database integration tests in our unit tests. Maybe this is related to the error. The unit tests arre running fine when using dotnet test

[richardwerkman]

Thank you, using your output I’ve been able to reproduce the issue locally.

using System.Threading.Tasks;

namespace Test
{
    public class ExampleBug
    {
        public async Task<(string, string)> ExampleBugMethod()
        {
            var (one, two) = await ExampleTupleMethod().ConfigureAwait(true);

            return (one, two);
        }

        private async Task<(string one, string two)> ExampleTupleMethod()
        {
            return ("test1", "test2");
        }
    }
}

Using var (tuple) seems to cause the issue. This was already known as seen in #125 but was closed without verifiying if the issue was actually fixed.

I’ll try to create a PR for this today 👍

[klemmchr]

I’ve send you a mail.