Dev container rework to support OmniSharp changes (octokit#2456)

* given the c# extension no longer is packaged with mono this is an attempt to get code nav and intellsense back in order for vscode

.devcontainer/Dockerfile

@@ -1,18 +1,13 @@
 # See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.234.0/containers/dotnet/.devcontainer/base.Dockerfile
 
 # [Choice] .NET version: 6.0, 5.0, 3.1, 6.0-bullseye, 5.0-bullseye, 3.1-bullseye, 6.0-focal, 5.0-focal, 3.1-focal
-ARG VARIANT="6.0-bullseye-slim"
-FROM mcr.microsoft.com/vscode/devcontainers/dotnet:0-${VARIANT}
+ARG VARIANT="6.0-bullseye"
+FROM mcr.microsoft.com/vscode/devcontainers/dotnet
 
-# [Choice] Node.js version: none, lts/*, 16, 14, 12, 10
-ARG NODE_VERSION="none"
-RUN if [ "${NODE_VERSION}" != "none" ]; then su vscode -c "umask 0002 && . /usr/local/share/nvm/nvm.sh && nvm install ${NODE_VERSION} 2>&1"; fi
-
-# [Optional] Uncomment this section to install additional OS packages.
-RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
-  && apt-get -y install --no-install-recommends python3-pip
+# "install" the dotnet 3.1 & 5.0 runtime for tests
+COPY --from=mcr.microsoft.com/dotnet/sdk:3.1 /usr/share/dotnet/shared /usr/share/dotnet/shared
+COPY --from=mcr.microsoft.com/dotnet/sdk:5.0 /usr/share/dotnet/shared /usr/share/dotnet/shared
 
+# # Add mkdocs for doc generation
+RUN apt-get update && export DEBIAN_FRONTEND=noninteractive && apt-get -y install --no-install-recommends python3-pip
 RUN pip3 install mkdocs
-
-# [Optional] Uncomment this line to install global node packages.
-# RUN su vscode -c "source /usr/local/share/nvm/nvm.sh && npm install -g <your-package-here>" 2>&1

.devcontainer/devcontainer.json

@@ -7,56 +7,33 @@
     "args": {
       // Update 'VARIANT' to pick a .NET Core version: 3.1, 5.0, 6.0
       // Append -bullseye or -focal to pin to an OS version.
-      "VARIANT": "3.1",
-      // Options
-      "NODE_VERSION": "none"
+      "VARIANT": "latest"
     }
   },
-
   // Set *default* container specific settings.json values on container create.
-  "settings": {},
-
+  "settings": {
+    "omnisharp.path": "latest",
+    "omnisharp.defaultLaunchSolution": "Octokit.sln",
+    "omnisharp.disableMSBuildDiagnosticWarning": false,
+    "omnisharp.useModernNet": true,
+    "omnisharp.enableAsyncCompletion": true,
+    "omnisharp.enableEditorConfigSupport": true,
+    "omnisharp.enableImportCompletion": true,
+    "omnisharp.enableRoslynAnalyzers": true,
+    "omnisharp.organizeImportsOnFormat": true
+  },
   // Add the IDs of extensions you want installed when the container is created.
   "extensions": [
     "ms-dotnettools.csharp",
-    "formulahendry.dotnet-test-explorer",
     "eamodio.gitlens",
     "fernandoescolar.vscode-solution-explorer",
     "redhat.vscode-yaml"
   ],
-
-  // Use 'forwardPorts' to make a list of ports inside the container available locally.
-  // "forwardPorts": [5000, 5001],
-
-  // [Optional] To reuse of your local HTTPS dev cert:
-  //
-  // 1. Export it locally using this command:
-  //    * Windows PowerShell:
-  //        dotnet dev-certs https --trust; dotnet dev-certs https -ep "$env:USERPROFILE/.aspnet/https/aspnetapp.pfx" -p "SecurePwdGoesHere"
-  //    * macOS/Linux terminal:
-  //        dotnet dev-certs https --trust; dotnet dev-certs https -ep "${HOME}/.aspnet/https/aspnetapp.pfx" -p "SecurePwdGoesHere"
-  //
-  // 2. Uncomment these 'remoteEnv' lines:
-  //    "remoteEnv": {
-    // 	      "ASPNETCORE_Kestrel__Certificates__Default__Password": "SecurePwdGoesHere",
-    //        "ASPNETCORE_Kestrel__Certificates__Default__Path": "/home/vscode/.aspnet/https/aspnetapp.pfx",
-    //    },
-    //
-    // 3. Do one of the following depending on your scenario:
-    //    * When using GitHub Codespaces and/or Remote - Containers:
-    //      1. Start the container
-    //      2. Drag ~/.aspnet/https/aspnetapp.pfx into the root of the file explorer
-    //      3. Open a terminal in VS Code and run "mkdir -p /home/vscode/.aspnet/https && mv aspnetapp.pfx /home/vscode/.aspnet/https"
-    //
-    //    * If only using Remote - Containers with a local container, uncomment this line instead:
-    //      "mounts": [ "source=${env:HOME}${env:USERPROFILE}/.aspnet/https,target=/home/vscode/.aspnet/https,type=bind" ],
-
-    // Use 'postCreateCommand' to run commands after the container is created.
-    // "postCreateCommand": "dotnet restore",
-
-    // Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
-    // "remoteUser": "vscode",
-    "features": {
-      "python": "latest"
-    }
+  // This is needed so that the C# extension can resolve to the correct SDK version
+  "remoteEnv": {
+    "PATH": "${containerWorkspaceFolder}/.dotnet:${containerEnv:PATH}",
+    "DOTNET_MULTILEVEL_LOOKUP": "0",
+    "TARGET": "net7.0",
+    "DOTNET_WATCH_SUPPRESS_LAUNCH_BROWSER": "true"
   }
+}