Ensure we don't run both project systems at once

When we were looking to see if Dev Kit was installed to know whether
we should trigger our own project system, we checked
_wasActivatedWithCSharpDevkit; but that wasn't set since we don't
await the server launch a few lines before. The field would be unset
and as a result we'd run both.

Fixes microsoft/vscode-dotnettools#40
Fixes dotnet/roslyn#68472
Fixes #5711

Author: jasonmalinowski

src/lsptoolshost/roslynLanguageServer.ts

@@ -207,7 +207,11 @@ export class RoslynLanguageServer {
         this._languageClient.onDidChangeState(async (state) => {
             if (state.newState === State.Running) {
                 await this._languageClient!.setTrace(languageClientTraceLevel);
-                await this.sendOpenSolutionNotification();
+                if (this._solutionFile) {
+                    await this.sendOpenSolutionNotification();
+                } else {
+                    await this.openDefaultSolution();
+                }
                 await this.sendOrSubscribeForServiceBrokerConnection();
                 this._eventBus.emit(RoslynLanguageServer.serverStateChangeEvent, ServerStateChange.Started);
             }
@@ -222,20 +226,6 @@ export class RoslynLanguageServer {
 
         // Register Razor dynamic file info handling
         this.registerRazor(this._languageClient);
-
-        // If Dev Kit isn't installed, then we are responsible for picking the solution to open, assuming the user hasn't explicitly
-        // disabled it.
-        if (!this._wasActivatedWithCSharpDevkit && options.commonOptions.defaultSolution !== 'disable' && this._solutionFile === undefined) {
-            if (options.commonOptions.defaultSolution !== '') {
-                this.openSolution(vscode.Uri.file(options.commonOptions.defaultSolution));
-            } else {
-                // Auto open if there is just one solution target; if there's more the one we'll just let the user pick with the picker.
-                const solutionUris = await vscode.workspace.findFiles('**/*.sln', '**/node_modules/**', 2);
-                if (solutionUris && solutionUris.length === 1) {
-                    this.openSolution(solutionUris[0]);
-                }
-            }
-        }
     }
 
     public async stop(): Promise<void> {
@@ -316,6 +306,24 @@ export class RoslynLanguageServer {
         }
     }
 
+    private async openDefaultSolution() {
+        const options = this.optionProvider.GetLatestOptions();
+
+        // If Dev Kit isn't installed, then we are responsible for picking the solution to open, assuming the user hasn't explicitly
+        // disabled it.
+        if (!this._wasActivatedWithCSharpDevkit && options.commonOptions.defaultSolution !== 'disable' && this._solutionFile === undefined) {
+            if (options.commonOptions.defaultSolution !== '') {
+                this.openSolution(vscode.Uri.file(options.commonOptions.defaultSolution));
+            } else {
+                // Auto open if there is just one solution target; if there's more the one we'll just let the user pick with the picker.
+                const solutionUris = await vscode.workspace.findFiles('**/*.sln', '**/node_modules/**', 2);
+                if (solutionUris && solutionUris.length === 1) {
+                    this.openSolution(solutionUris[0]);
+                }
+            }
+        }
+    }
+
     private async sendOrSubscribeForServiceBrokerConnection() {
         const csharpDevKitExtension = vscode.extensions.getExtension<CSharpDevKitExports>(csharpDevkitExtensionId);
         if (csharpDevKitExtension) {