Add path to dotnet so child processes can use the CLI

.vscode/launch.json

@@ -7,7 +7,6 @@
             "request": "launch",
             "runtimeExecutable": "${execPath}",
             "args": [
-                "--disable-extensions",
                 "--extensionDevelopmentPath=${workspaceRoot}"
             ],
             "stopOnEntry": false,

src/main.ts

@@ -7,6 +7,7 @@ import * as OmniSharp from './omnisharp/extension';
 import * as coreclrdebug from './coreclr-debug/activate';
 import * as util from './common';
 import * as vscode from 'vscode';
+import * as path from 'path';
 
 import { ActivationFailure, ActiveTextEditorChanged } from './omnisharp/loggingEvents';
 import { WarningMessageObserver } from './observers/WarningMessageObserver';
@@ -148,6 +149,8 @@ export async function activate(context: vscode.ExtensionContext): Promise<CSharp
         return null;
     }
 
+    await tryAddDotNetToPath();
+
     let telemetryObserver = new TelemetryObserver(platformInfo, () => reporter);
     eventStream.subscribe(telemetryObserver.post);
 
@@ -227,3 +230,24 @@ async function ensureRuntimeDependencies(extension: vscode.Extension<CSharpExten
     return installRuntimeDependencies(extension.packageJSON, extension.extensionPath, installDependencies, eventStream, platformInfo);
 }
 
+async function tryAddDotNetToPath() {
+    const sdkExtension = vscode.extensions.getExtension("ms-dotnettools.vscode-dotnet-pack");
+    if (sdkExtension) {
+        try {
+            if (!sdkExtension.isActive) {
+                await sdkExtension.activate();
+            }
+
+            // Invoking acquireStatus updates the process.env.PATH with the folder that contains the dotnet cli.
+            // This will allow child processes such as OmniSharp to use the dotnet cli.
+            const request = { version: '5.0', requestingExtensionId: 'ms-dotnettools.csharp' };
+            const statusResult = await vscode.commands.executeCommand<{ dotnetPath: string }>('dotnet-sdk.acquireStatus', request);
+
+            return statusResult.dotnetPath?.length > 0;
+        }
+        catch {
+        }
+    }
+
+    return false;
+}