Extension hangs with high CPU usage

Issue Description

When loading some projects, the C# extension hangs, and the “mono” process is stuck running at at 100%+ CPU utilization. No language services that involve the language server (IntelliSense, hover, etc.) work.

Steps to Reproduce

On a Mac, clone the Microsoft Python Language Server project (https://github.com/Microsoft/python-language-server) Launch VSCode and open the primary workspace for the cloned repo Install the C# extension if it’s not already installed

Open the “Activity Monitor” and sort the processes by CPU. Note that the “mono” process is now running at 100%+ In VSCode, open the output view and switch to the “OmniSharp Log”. Note that the last line says: Loading project: /python-language-server/src/LanguageServer/Impl/Microsoft.Python.LanguageServer.csproj

I allowed it to run for 15 minutes before terminating it.

I presume this is an issue with OmniSharp, as opposed to the javascript portion of the language server.

I tried rebuilding previous versions of the C# extension (1.16.2, 1.15.2) to see if this was a recent regression, but I was able to repro the same problem with those versions.

I tried the same scenario on Windows, and it worked fine. The OmniSharp log contained additional contents including the line Successfully loaded project file. On the Mac, this was never emitted to the log.

OmniSharp log

Starting OmniSharp server at 12/24/2018, 11:38:57 PM
    Target: /Users/eric/source/python-language-server/src/PLS.sln

OmniSharp server started.
    Path: /Users/eric/.vscode/extensions/ms-vscode.csharp-1.17.1/.omnisharp/1.32.8/run
    PID: 10020

[info]: OmniSharp.Stdio.Host
        Starting OmniSharp on MacOS 10.13.6 (x64)
[info]: OmniSharp.Services.DotNetCliService
        DotNetPath set to dotnet
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
        Located 1 MSBuild instance(s)
            1: StandAlone 15.0 - "/Users/eric/.vscode/extensions/ms-vscode.csharp-1.17.1/.omnisharp/1.32.8/omnisharp/msbuild/15.0/Bin"
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
        MSBUILD_EXE_PATH environment variable set to '/Users/eric/.vscode/extensions/ms-vscode.csharp-1.17.1/.omnisharp/1.32.8/omnisharp/msbuild/15.0/Bin/MSBuild.dll'
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
        Registered MSBuild instance: StandAlone 15.0 - "/Users/eric/.vscode/extensions/ms-vscode.csharp-1.17.1/.omnisharp/1.32.8/omnisharp/msbuild/15.0/Bin"
            MSBuildExtensionsPath = /Users/eric/.vscode/extensions/ms-vscode.csharp-1.17.1/.omnisharp/1.32.8/omnisharp/msbuild
            BypassFrameworkInstallChecks = true
            CscToolPath = /Users/eric/.vscode/extensions/ms-vscode.csharp-1.17.1/.omnisharp/1.32.8/omnisharp/msbuild/15.0/Bin/Roslyn
            CscToolExe = csc.exe
            MSBuildToolsPath = /Users/eric/.vscode/extensions/ms-vscode.csharp-1.17.1/.omnisharp/1.32.8/omnisharp/msbuild/15.0/Bin
[info]: OmniSharp.Cake.CakeProjectSystem
        Detecting Cake files in '/Users/eric/source/python-language-server/src'.
[info]: OmniSharp.Cake.CakeProjectSystem
        Could not find any Cake files
[info]: OmniSharp.WorkspaceInitializer
        Project system 'OmniSharp.DotNet.DotNetProjectSystem' is disabled in the configuration.
[info]: OmniSharp.MSBuild.ProjectSystem
        Detecting projects in '/Users/eric/source/python-language-server/src/PLS.sln'.
[info]: OmniSharp.MSBuild.ProjectManager
        Queue project update for '/Users/eric/source/python-language-server/src/LanguageServer/Impl/Microsoft.Python.LanguageServer.csproj'
[info]: OmniSharp.MSBuild.ProjectManager
        Queue project update for '/Users/eric/source/python-language-server/src/UnitTests/Core/Impl/UnitTests.Core.csproj'
[info]: OmniSharp.MSBuild.ProjectManager
        Queue project update for '/Users/eric/source/python-language-server/src/Analysis/Engine/Impl/Microsoft.Python.Analysis.Engine.csproj'
[info]: OmniSharp.MSBuild.ProjectManager
        Queue project update for '/Users/eric/source/python-language-server/src/Analysis/Engine/Test/Microsoft.Python.Analysis.Engine.Tests.csproj'
[info]: OmniSharp.Script.ScriptProjectSystem
        Detecting CSX files in '/Users/eric/source/python-language-server/src'.
[info]: OmniSharp.Script.ScriptProjectSystem
        Could not find any CSX files
[info]: OmniSharp.WorkspaceInitializer
        Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.CSharpWorkspaceOptionsProvider
[info]: OmniSharp.WorkspaceInitializer
        Configuration finished.
[info]: OmniSharp.Stdio.Host
        Omnisharp server running using Stdio at location '/Users/eric/source/python-language-server/src' on host 10001.
[info]: OmniSharp.MSBuild.ProjectManager
        Loading project: /Users/eric/source/python-language-server/src/LanguageServer/Impl/Microsoft.Python.LanguageServer.csproj

C# log

<No output>

Environment information

VSCode version: 1.30.1 C# Extension: 1.17.1

Mono Information

OmniSharp using built-in mono

Dotnet Information

.NET Core SDK (reflecting any global.json): Version: 2.2.101 Commit: 236713b0b7

Runtime Environment: OS Name: Mac OS X OS Version: 10.13 OS Platform: Darwin RID: osx.10.13-x64 Base Path: /usr/local/share/dotnet/sdk/2.2.101/

Host (useful for support): Version: 2.2.0 Commit: 1249f08fed

.NET Core SDKs installed: 2.2.101 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed: Microsoft.AspNetCore.All 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All] Microsoft.AspNetCore.App 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.NETCore.App 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs: https://aka.ms/dotnet-download

Visual Studio Code Extensions

Extension	Author	Version
cpptools	ms-vscode	0.20.1
csharp	ms-vscode	1.17.1
python	ms-python	2018.12.1
tslint	eg2	1.0.42
vscode-docker	PeterJausovec	0.4.0
vscode-proto3	zxh404	0.2.2

[akshita31]

@erictraut @Jma353 Could you try with the latest release of the C# extension? We have made some performance improvements that should make the experience better.

[mic-hnk]

I found a hint in #3079 and removing IDisposable implementations actually helped.