Fix dotnet build file.cs with MSBuild logger options

[xoofx]

Hello, this PR fixes file-based dotnet build detection when MSBuild logger options are passed before the C# file, for example:

dotnet build --logger:xyz Program.cs
dotnet build -l:xyz Program.cs

Previously, Program.cs could stop being recognized as a file-based app entry point and instead be forwarded to physical MSBuild as a project file. MSBuild would then try to parse the C# file as XML and fail with MSB4025.

I assume that this could be backported to net10.0 ?

Root cause

dotnet build did not define --logger / -l as known CLI options. As a result, logger arguments were handled as unmatched/MSBuild-style tokens during parsing, which interfered with the SlnOrProjectOrFileArgument values used by file-based build detection.

Fix

Adds hidden --logger / -l options to BuildCommandDefinition and forwards them to MSBuild as:

--logger:<value>

The option uses AllowSingleArgPerToken() so forms like the following preserve Program.cs as the single file-based entry-point argument:

dotnet build --logger xyz Program.cs
dotnet build --logger:xyz Program.cs
dotnet build -l xyz Program.cs
dotnet build -l:xyz Program.cs

Tests

Added regression coverage verifying that all logger forms above still produce a VirtualProjectBuildingCommand and forward --logger:xyz to MSBuild, instead of treating Program.cs as a project file.

[Copilot]

Pull request overview

This PR updates dotnet build so --logger / -l are parsed as recognized CLI options, preventing file-based Program.cs builds from being misclassified as regular MSBuild project inputs when logger options appear before the .cs file.

Changes:

• Added hidden --logger / -l option handling to BuildCommandDefinition.
• Forwarded parsed logger values to MSBuild in normalized --logger:<value> form.
• Added regression tests covering file-based build detection with logger options before Program.cs.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/Cli/Microsoft.DotNet.Cli.Definitions/Commands/Build/BuildCommandDefinition.cs	Adds hidden logger option parsing/forwarding for dotnet build.
test/dotnet.Tests/CommandTests/MSBuild/GivenDotnetBuildInvocation.cs	Adds regression tests for file-based build detection with logger arguments.

[xoofx]

cc: @marcpopMSFT or @dsplaisted if you can help to accept/merge this PR, thank you! ☺️

[dsplaisted]

Thanks! I would recommend moving this to CommonOptions and then also adding it to publish, pack, clean, and restore, so it works in those cases too.

[xoofx]

Thanks! I would recommend moving this to CommonOptions and then also adding it to publish, pack, clean, and restore, so it works in those cases too.

Good call! Fixed via 829780f

[xoofx]

@dsplaisted will it be possible to merge this PR ?

[dsplaisted]

@xoofx sorry for the delay, there are some merge conflicts and test failures that need to be resolved.

[xoofx]

@dsplaisted the branch has been updated with merge conflicts resolved.

[dsplaisted]

@xoofx Thanks, could you look at the test failures? Looks like there are two of them now.

[xoofx]

Latest commit is green, just rebased