[release/10.0.1xx] Fix working directory of simple file-based apps

[github-actions]

Backport of #51828 to release/10.0.1xx

/cc @jjonescz

Description

Fixes a bug where dotnet run path/to/file.cs has a wrong working directory (it uses directory of the file, not the current working directory like usual for dotnet run). This only affects simple file-based apps (which skip MSBuild and invoke the C# compiler directly), hence it can be worked around with --no-cache (which skips this optimized path).

Customer impact

This was reported by several customers on GitHub. It has been fixed in 10.0.200 but it sill continues to be reported. Hence I think it would be good to backport this simple fix to 10.0.1xx.

Regression

Not since GA. This might have worked in some .NET 10 previews though (before we had the optimized path that introduced the bug).

Risk

Low. A simple change with narrow impact. Already released in 10.0.200. Unit test coverage.

[Youssef1313]

it uses directory of the file, not the current working directory like usual for dotnet run.

The usual project-based dotnet run doesn't use the current working directory AFAIK. It uses RunWorkingDirectory MSBuild property. I didn't check what would it default to, but I thought it's worth noting. I'm not sure if the RunXYZ properties are relevant for you for file-based apps and if you want to respect them.

[jjonescz]

it uses directory of the file, not the current working directory like usual for dotnet run.

The usual project-based dotnet run doesn't use the current working directory AFAIK. It uses RunWorkingDirectory MSBuild property. I didn't check what would it default to, but I thought it's worth noting. I'm not sure if the RunXYZ properties are relevant for you for file-based apps and if you want to respect them.

Yes, good point, they are respected. They default to the current working directory. And simple file-based apps cannot overwrite them (if they did, they wouldn't be simple anymore and would use msbuild and hence also RunWorkingDirectory). So using the current working directory is the correct default.

[jjonescz]

/ba-g known: #53796, #53789