Add support for file-based apps to dotnet-ef tools

[jjonescz]

Resolves #38158.

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[roji]

@jjonescz can you please open an issue clearly detailing what this is meant to fix?

[Copilot]

Pull request overview

This PR adds first-class support in dotnet-ef for “file-based apps” (single .cs files) by allowing users to point tooling at a .cs file and ensuring metadata extraction works for those inputs.

Changes:

• Add a --file option (mutually exclusive with --project) and resolve it when selecting the project path.
• Switch MSBuild metadata extraction to use dotnet build (instead of dotnet msbuild) when the input is a .cs file.
• Add a new test validating build/metadata extraction for a file-based app.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test/dotnet-ef.Tests/FileBasedAppTest.cs	New test covering metadata extraction and build output for a .cs file-based app.
src/dotnet-ef/RootCommand.cs	Adds --file handling and mutual exclusion logic with --project.
src/dotnet-ef/Properties/Resources.resx	Adds new option/error strings and updates option descriptions.
src/dotnet-ef/Properties/Resources.Designer.cs	Updates strongly-typed resource accessors for new strings.
src/dotnet-ef/ProjectOptions.cs	Adds the --file command-line option.
src/dotnet-ef/Project.cs	Uses dotnet build (vs dotnet msbuild) for .cs inputs during metadata extraction.

Files not reviewed (1)

• src/dotnet-ef/Properties/Resources.Designer.cs: Language not supported

[Copilot]

Pull request overview

Copilot reviewed 5 out of 6 changed files in this pull request and generated 1 comment.

Files not reviewed (1)

• src/dotnet-ef/Properties/Resources.Designer.cs: Language not supported

[AndriySvyryd]

I think we shouldn't introduce --file. Adding support for file-based apps doesn't change the overall semantics of the input: --project indicates the code that when compiled produces an assembly with migrations, --startup-project indicates the code that when compiled produces an assembly that contains EF configuration (.AddDbContext),

[jjonescz]

Right, so you are saying we should accept .cs files as arguments to --project and --startup-project? That works for me. I was trying to be more consistent with other commands (e.g., dotnet run has also --project and --file arguments, and some other dotnet CLI commands are also like that). But we could definitely add the file option later, and can start with accepting the file as project now.

[AndriySvyryd]

Right, so you are saying we should accept .cs files as arguments to --project and --startup-project? That works for me. I was trying to be more consistent with other commands (e.g., dotnet run has also --project and --file arguments, and some other dotnet CLI commands are also like that). But we could definitely add the file option later, and can start with accepting the file as project now.

Yes. We could add --file and --startup-file as synonyms, I just think that would be confusing for users familiar with dotnet-ef

[Copilot]

Pull request overview

Copilot reviewed 3 out of 4 changed files in this pull request and generated 3 comments.

Files not reviewed (1)

• src/dotnet-ef/Properties/Resources.Designer.cs: Language not supported

[AndriySvyryd]

Filed #38159 to decide which direction we should go

[AndriySvyryd]

Thanks!