Diagnostics from single file vs project are not deduped correctly

I’m not sure if I simply managed to mess up my local set up but I don’t think so - I can repro it on both Windows and macOS.

Environment data

VS Code version: 1.17.2 C# Extension version: 1.13.0-beta4

Steps to reproduce

Give the following code, in a .NET Core 1.1 project (project type is irrelevant, I can repro the same error i.e. with CSX)

namespace Sonova.Nephele.Shared.Web.AspNetCore
{
    public class ErrorData
    {
        public string Message { get; set; }
    }
}dddd

Hover over dddd. Then hover again, and again.

Expected behavior

Diagnostic is de-duped.

We make 2 calls to /codecheck:

• once with current file context
• once with no file context (against all projects)

As soon as the second one completes, the 2 diagnostic entry shows up next to the original one.

Actual behavior

The diagnostic is not deduped:

It also shows up twice in the Problems panel.

Note that the project is not multi-targeted for 2 frameworks. As mentioned, same behavior can be observed for i.e. CSX.

[rchande]

@DustinCampbell @mholo65 @david-driscoll

The C# extension makes 2 diagnostics calls: one with a filename, and one with no filename which is supposed to get all the diagnostics for a “project”. (This actually means all the diagnostics in the O# Workspace’s CurrentSolution). When we make a request with a filename, we get back the correct diagnostics. When we make a request with no filename, Omnisharp returns every diagnostic twice. The C# extension faithfully adds each diagnostic to the error list twice.

It looks like Omnisharp regressed this when we added cake support. Cake added another CodeCheckRequest handler that also uses the C# CodeCheckService. The cake code check handler properly reports that it support “cake” files and there is code in EndPointHandler.cs that sniffs the filepath to figure out what the extension is. However, if there’s no file name, like in the “project” case, the C# and Cake code check handlers both get invoked, and both produce the same diagnostics, leading to duplicates.

I’m not sure what the best fix is there. I don’t think adding a “language” field to the code check request would be the right thing–when we request diagnostics for all projects we probably want to include cake projects. Should we have the cake handler only provide diagnostics in cake files?

[rchande]

@mholo65 Working on it–almost ready.