File attachments aren't added if they are prefixed with "\\?\"

[dro123]

When reporting a bug, please provide the following information to speed up triage:

• NUnit and NUnit3TestAdapter versions
  NUnit 3.14.0
  NUnit3TestAdapter 4.5.0

• Visual Studio edition and full version number (see Help About)
  Visual Studio Professional 2022 64bit Version 17.8.3

• A short repro, preferably attached or pointing to a git repo or gist
  https://github.com/nunit/nunit3-vs-adapter/blob/master/src/NUnitTestAdapter/TestConverter.cs#L382C24-L382C24
  Here the file path of the attachment is check with "new Uri()".
  The Uri class throws an exception if the path prefix "\?" is used even though it's a valid path for Windows:
  https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file?redirectedfrom=MSDN#maximum-path-length-limitation
  This causes the attachments to be ignored even though they are actually there and valid.
  A workaround would be to remove "\?" from the beginning if it's there before converting it to an Uri.

• What .net platform and version is being targeted
  .NET Framework 4.8

• If TFS/VSTS issue, what version, hosted or on-premises, and what build task you see this in
  None

[OsirisTerje]

Can you add a small repro for this?

How do you get file paths like that? Is it to circumvent max path length?

[dro123]

Yes it's to handle long paths.
It's not an issue nowadays, but when I originally added the code it was an issue and that's why it's still in that format.
I updated my code and removed the \\?\ from there and it works fine now.
I thought I'm probably not the only one and it's probably an easy fix, that's why I reported it :-)

Project file:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Library</OutputType>
    <TargetFramework>net8.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
    <PackageReference Include="NUnit" Version="4.0.1" />
    <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
  </ItemGroup>
</Project>

Test code:

using NUnit.Framework;

[TestFixture]
public class Tests
{
    [Test]
    public void LongPathTest()
    {
        TestContext.AddTestAttachment(@"\\?\C:\Temp\test.txt");
        Assert.Fail();
    }
}

Run tests with:
dotnet test

Output:
Ignoring attachment with path '\\?\C:\Temp\test.txt' due to problem with path: Invalid URI: The hostname could not be parsed.

[OsirisTerje]

Thanks! I'll add that to the test we have, and get this fixed.

[stevenaw]

The next release of the framework, 4.2, should include a change which may help here by avoiding the need to explicitly specify the "\?" prefix: nunit/nunit#4353

Note that that change will still only include the prefix in the output file itself if it is explicitly specified as part of the AddTestAttachment call so this adapter-side issue may still be needed if that's desired.