[Hot Reload] `ENC0003: Updating 'attribute' requires restarting the application` caused by `AssemblyInformationalVersionAttribute`

[jeromelaban]

Describe the bug

During Hot Reload, with .NET 7 or .NET 8, building WPF (or Uno Platform) app and hot reloading it in VS 2022 (17.7 or 17.8) can produce the following error:

MyApp.AssemlyInfo.cs (line 17): error ENC0003: Updating 'attribute' requires restarting the application.

Where the generated file is

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
 
using System;
using System.Reflection;
 
[assembly: System.Reflection.AssemblyCompanyAttribute("test")]
[assembly: System.Reflection.AssemblyConfigurationAttribute("Debug")]
[assembly: System.Reflection.AssemblyFileVersionAttribute("1.0.0.0")]
[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0")]
[assembly: System.Reflection.AssemblyProductAttribute("test")]
[assembly: System.Reflection.AssemblyTitleAttribute("test")]
[assembly: System.Reflection.AssemblyVersionAttribute("1.0.0.0")]

Line 17 being:

[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0")]

Having tried to debug this issue, if feels like the Roslyn HotReload workspace is, for some reason, generating a AssemblyInformationalVersionAttribute sometimes:

sdk/src/BuiltInTools/dotnet-watch/HotReload/CompilationHandler.cs

Line 69 in 6710347

var project = await _workspace.OpenProjectAsync(context.FileSet.Project.ProjectPath, cancellationToken: cancellationToken);

but since there's no way to get binlogs for the workspace's solution load, it's difficult to troubleshoot why the original value and the hotreloaded values may be different.

To Reproduce

The part being unclear is the set of conditions for this to happen, but here's a summary:

1. Create a WPF app
2. Hot reload it
3. Stop the hot reload completely by stopping the app
4. Start the hot reload session again

Workaround

Disabling assemblyversion generation helps:

<GenerateAssemblyInfo Condition="'$(Configuration)'=='Debug'">false</GenerateAssemblyInfo>

But can cause CA1416 to appear. Disabling AssemblyFileVersionAttribute and AssemblyInformationalVersionAttribute can also help as more precise:

sdk/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.GenerateAssemblyInfo.targets

Line 75 in 6710347

<Target Name="GetAssemblyAttributes"

Further technical details

Versions

• .NET 7.0.403 or .NET 8.0.100 RC2
• VS 17.7.6 or VS 17.8 Preview 6

[baronfel]

This might be related to Sourcelink being on by default in .Net 8 SDKs - it would impact the value in the AssemblyInformationalVersion if git commits were being made between hot reload refreshes.

[KalleOlaviNiemitalo]

If this were a matter of new Git commits, then I'd expect the generated file to include some commit ID, rather than just AssemblyInformationalVersionAttribute("1.0.0").

[baronfel]

If this were a matter of new Git commits, then I'd expect the generated file to include some commit ID, rather than just AssemblyInformationalVersionAttribute("1.0.0").

Good call - I'm just a little sensitive to potentially SourceLink-related regressions, since we've seen a few of those in the latter part of this release.

[jeromelaban]

@KalleOlaviNiemitalo it may be so, the file you're seeing here may be one of the updated versions for that file (original or updated). That's the problem of generated files on disk by msbuild, they get re-generated by both VS and the hot reload workspace.

[jeromelaban]

Reading further about this SourceControlInformationFeatureSupported, it looks like this is set by VS in the environment. Is it something that should be propagated to the HR workspace as well?

[jeromelaban]

Ok, so thanks to your insights, I now have a reliable repro:

• Create a net8.0 WPF app
• Create a class library referenced by the WPF app, use code from the library in the WPF app project
• Add both to a git repository for the solution's folder, and commit the files.
• Build the app once
• Open the obj\Debug\net8.0\MyLibrary.AssemblyInfo.cs, notice the Commit ID in AssemblyInformationalVersionAttribute
• Start the app
• Make an update to code in the class library, hot reload it
• Notice that the AssemblyInformationalVersionAttribute does not contain the ID anymore and fails with ENC0003

[tmat]

@jeromelaban I followed the steps above but can't repro :(. The attribute is not changed, still contains the commit SHA.

[tmat]

@jeromelaban Could you please capture and share the binary logs for design time build?

See https://github.com/dotnet/msbuild/blob/main/documentation/wiki/Providing-Binary-Logs.md#capturing-binary-logs-through-visual-studio

When setting env variables before starting VS following the above instructions, could you also set

set Microsoft_CodeAnalysis_EditAndContinue_LogDir=%TEMP%\enclog

and share the content?