Mono-built SDK has error loading System.Reflection.MetadataLoadContext from MSBuild

[mthalman]

All, or most, of the tests are getting this error:

System.InvalidOperationException : Failed to execute /vmr/test/Microsoft.DotNet.SourceBuild.SmokeTests/bin/Release/net8.0/.dotnet/dotnet build /bl:/vmr/test/Microsoft.DotNet.SourceBuild.SmokeTests/bin/Release/net8.0/logs/BasicScenarioTests_Console_CSharp-build.binlog
Exit code: 1
MSBuild version 17.7.0-preview-23315-03+e33c36720 for .NET
MSBUILD : error MSB1021: Cannot create an instance of the logger. Microsoft.Build.BackEnd.Logging.CentralForwardingLogger Could not load type of field 'Microsoft.Build.Shared.TypeLoader:_context' (4) due to: Could not load file or assembly 'System.Reflection.MetadataLoadContext, Version=7.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies.

This is a regression and first showed up in this build (internal link).

This is blocking source-build and must be fixed for 8.0 Preview 6.

[omajid]

cc @Swapnali911

[mthalman]

Moving to the runtime repo to investigate.

This regression occurred between the following commits in the VMR: https://github.com/dotnet/dotnet/compare/9dc0fc5..b294512

Notably, there are changes to mono included there from the changes in dotnet/runtime#87087. cc @kouvel

[kouvel]

The failure doesn't sound relevant to the changes in dotnet/runtime#87087. That PR only has minor changes to add 3 internal calls for events methods that are not actually called, and a minor change to the inclusion of a file, which I believe is correct, though perhaps if something is wrong it may cause build-time issues and I wouldn't expect any run-time issues.

[mthalman]

@marek-safar - Can this get taken a look at soon? This needs to be fixed for Preview 6.

[mthalman]

Here's some context on what the tests are doing:

First, we use the source-build infrastructure to build .NET from source to produce an SDK. For the runtime repo, it uses the --usemonoruntime build option. Tests are run against that built SDK for a variety of scenarios. In this case, the tests that are failing are all attempting to do the same sort of thing. They create a new project using dotnet new (such as a console app template) and then simply attempt to build the project, specify a binlog output path. Here's an example:

/vmr/test/Microsoft.DotNet.SourceBuild.SmokeTests/bin/Release/net8.0/.dotnet/dotnet build /bl:/vmr/test/Microsoft.DotNet.SourceBuild.SmokeTests/bin/Release/net8.0/logs/BasicScenarioTests_Console_CSharp-build.binlog

This is the command which fails for these tests.

[janani66]

Wanted to add that we see a similar failure on ppc64le RHEL machine ( uses MONO runtime) with a dotnet built from preview5 using source-build i.e. a simple "Hello World" console app doesn't work.

$dotnet new console
The template "Console App" was created successfully.

Processing post-creation actions...
Restoring /root/test_hello/test_hello.csproj:
MSBUILD : error MSB1021: Cannot create an instance of the logger. Microsoft.Build.Logging.ConfigurableForwardingLogger Could not load type of field 'Microsoft.Build.Shared.TypeLoader:_context' (4) due to: Could not load file or assembly 'System.Reflection.MetadataLoadContext, Version=7.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies.
Restore failed.
Post action failed.
Manual instructions: Run 'dotnet restore'