"CS8700: Multiple analyzer config files cannot be in the same directory" but only one StyleCop file

Question

I'm trying to learn to use StyleCop on a personal project. It's not a very big one, and the solution structure is below:

- MySolution (2 of 2 projects)
   - Solution Items
      - .editorconfig
      - .gitignore
      - CODEOWNERS
      - my-pipeline-workflow.yml
      - README.md
      - stylecop.json
   - MyMainProject
      - Dependencies
      - .editorconfig (pointer Solution Items copy)
      - OneOfManyCsFiles.cs
      - stylecop.json (pointer Solution Items copy)
   - MyTestProject
      - Dependencies
      - .editorconfig (pointer Solution Items copy)
      - OneOfManyTestCsFiles.cs
      - stylecop.json (pointer Solution Items copy)

And here is how the folders themselves are structured:

- RepoFolder
   - .github
      - workflows
         - my-pipeline-workflow.yml
   - src
      - MyMainProject.csproj
      - OneOfManyCsFiles.cs
   - test
      - MyTestProject.csproj
      - OneOfManyTestCsFiles.cs
   - .editorconfig
   - .gitignore
   - CODEOWNERS
   - MySolution.sln
   - README.md
   - stylecop.json

Everything worked prior to adding the file for StyleCop. I could build and test just fine in Visual Studio. For whatever reason, adding the file for StyleCop (and maybe the .editorconfig file) seems to have caused this error on build:

CSC: error CS8700: Multiple analyzer config files cannot be in the same directory ('/home/runner/work/MySolution/MySolution').
[/home/runner/work/MySolution/MySolution/src/MyMainProject.csproj]

As far as I understand, the StyleCop file is the only analyzer file and it's referenced in multiple places. Does the .editorconfig somehow count as another analyzer file? If so, how do I get them to play nice?

Suppressing the error in .editorconfig does nothing. I haven't been able to find any helpful documentation when searching the error alone either.

Bunyabunya

Answer 1

Turns out the issue is trying to reference the .editorconfig file from the projects. I deleted the references and just left the file as a solution item in the root of the solution. Most of the settings I have worked fine from there, but I had some StyleCop severity settings that weren't getting picked up properly for the analyzer.

To fix that, I changed to using GlobalSuppressions.cs files for each project individually. I could probably have bundled these together and referenced them like I'm doing with the stylecop.json file, but decided that limiting the suppression scopes was probably more appropriate.

Bunyabunya

Actually, you should be able to add project-specific .editorconfig files nested inside subfolders, simply by not specifying root = true option (reference) – Enroll

@Enroll - True, though my issue was that I was using a reference to the same file in two different projects. The goal was to not duplicate files where it wasn't needed. – Bunyabunya

Yes, I understood the problem, and your solution works correctly. I was pointing out that, to improve consistency, you could stick with a single type of configuration file (EditorConfig) by using a root .editorconfig not referenced in the projects (like you did) and a nested .editorconfig file inside each project which needed to tune settings, avoiding the use of GlobalSuppressions.cs. – Enroll

@Enroll I encountered the same error with your structure. But it may be visual studio bug. I ensured I didn't use the reference of the same file. – Apropos

@Apropos yes, it seems a weird behavior from Visual Studio; I'm not using Visual Studio anymore, but IIRC .editorconfig files should be there, but not declared in the project file. So I think that the fix you proposed in your answer below actually is what I expect Visual Studio to set the project file to – Enroll

Answer 2

Just for other googler's reference.

I used NiccoMlt's structure, but encountered CS8700. I solved this by removing the following from the problematic project file.

  <ItemGroup>
    <EditorConfigFiles Include=".editorconfig" />
  </ItemGroup>
  <ItemGroup>
    <None Remove=".editorconfig" />
  </ItemGroup>

I don't know why this is inserted, but it solved my problem.

Apropos

Note that you might need to restart VS for this to take effect on Intellisense. – Sybaris