Are debug NGEN images OK?

[richlander]

I interrogated .NET Framework 1909 and 1903 images, for 32- and 64-bit.

C:\Users\rich>docker run --rm mcr.microsoft.com/dotnet/framework/runtime:4.8-windowsservercore-1909 c:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen display | findstr debug
Accessibility, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>
System.Net, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>

C:\Users\rich>docker run --rm mcr.microsoft.com/dotnet/framework/runtime:4.8-windowsservercore-1909 c:\Windows\Microsoft.NET\Framework\v4.0.30319\ngen display | findstr debug
Accessibility, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>
System.Net, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>

C:\Users\rich>docker run --rm mcr.microsoft.com/dotnet/framework/runtime:4.8-windowsservercore-1903 c:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen display | findstr debug
Accessibility, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>
System.Net, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>

C:\Users\rich>docker run --rm mcr.microsoft.com/dotnet/framework/runtime:4.8-windowsservercore-1903 c:\Windows\Microsoft.NET\Framework\v4.0.30319\ngen display | findstr debug
Accessibility, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>
System.Net, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a <debug>

[mthalman]

@nattress - Can you provide some context on what <debug> means and why it would be there for these assemblies and not others?

[richlander]

From @jkotas:

These images are compiled with “optimization off”, e.g. here is a command that creates System.Drawing.dll image.

ngen install /nodependencies /debug System.Drawing.dll

These images are used if you configure VS debugger to disable optimizations for everything, so that the whole framework gets the nicer “optimizations off” debugging experience. Nobody does that (intentionally).

We should not have any of these in the docker images.

[richlander]

We need to find out why this is happening.

[mthalman]

I've logged an internal bug for this work: https://microsoft.visualstudio.com/OS/_workitems/edit/26625219