Track debugging sessions until csdevkit is initialized

src/coreclrDebug/activate.ts

@@ -310,21 +310,3 @@ export class DebugAdapterExecutableFactory implements vscode.DebugAdapterDescrip
         return executable;
     }
 }
-
-let _brokeredServicePipeName: string | undefined;
-
-/**
- * Initialize brokered service pipe name from C# dev kit, if available.
- *
- * @param csDevKitPipeName Activated brokered service pipe name activated by {@link CSharpDevKitExports}.
- */
-export function initializeBrokeredServicePipeName(csDevKitPipeName: string) {
-    _brokeredServicePipeName = csDevKitPipeName;
-}
-
-/**
- * Fetch the brokered service pipe name from C# dev kit, if available.
- */
-export function getBrokeredServicePipeName(): string | undefined {
-    return _brokeredServicePipeName;
-}

src/coreclrDebug/provisionalDebugSessionTracker.ts

@@ -0,0 +1,93 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as vscode from 'vscode';
+
+/**
+ * This tracks a debug session until C# dev kit is loaded (if present) and STOPS tracking any existing
+ * debug session after C# dev kit is loaded.
+ * The idea is to avoid a race condition if a debugging session starts before C# dev kit is initialized,
+ * since the brokered service pipe name will be sent with a 'launch' command.
+ * If the extension loads during an existing session, rather than not initializing any C# dev kit services (such as hot reload),
+ * this sends a custom request to the engine with the brokered service pipe name in order to initialize it.
+ */
+export class ProvisionalDebugSessionTracker {
+    private _sessions: Set<vscode.DebugSession> | undefined = new Set<vscode.DebugSession>();
+
+    private _onDidStartDebugSession: vscode.Disposable | undefined;
+    private _onDidTerminateDebugSession: vscode.Disposable | undefined;
+
+    private _brokeredServicePipeName: string | undefined;
+
+    /**
+     * Initializes the debug session handlers.
+     */
+    initializeDebugSessionHandlers(context: vscode.ExtensionContext): void {
+        this._onDidStartDebugSession = vscode.debug.onDidStartDebugSession(this.onDidStartDebugSession.bind(this));
+
+        this._onDidTerminateDebugSession = vscode.debug.onDidTerminateDebugSession((session: vscode.DebugSession) => {
+            this.onDidTerminateDebugSession(session);
+        });
+
+        context.subscriptions.push(this._onDidStartDebugSession);
+        context.subscriptions.push(this._onDidTerminateDebugSession);
+    }
+
+    /**
+     * Tracks a debug session until it is terminated.
+     * @param session Debug session.
+     */
+    onDidStartDebugSession(session: vscode.DebugSession): void {
+        if (session.type !== 'coreclr') {
+            return;
+        }
+
+        this._sessions?.add(session);
+    }
+
+    /**
+     * Notifies that a debug session has been terminated.
+     */
+    onDidTerminateDebugSession(session: vscode.DebugSession): void {
+        this._sessions?.delete(session);
+    }
+
+    /**
+     * If there is any active debug session, this notifies the engine that csdevkit was loaded.
+     * @param csDevKitPipeName Brokered service pipe name activated by {@link CSharpDevKitExports}.
+     */
+    async onCsDevKitInitialized(csDevKitPipeName: string): Promise<void> {
+        this._brokeredServicePipeName = csDevKitPipeName;
+
+        const sessions = this._sessions;
+        if (sessions != undefined) {
+            // Debugging session already started, send a custom DAP request to the engine.
+            sessions.forEach((s) => s.customRequest('initializeBrokeredServicePipeName', csDevKitPipeName));
+        }
+
+        // Since C# dev kit was initialized, we no longer need to track debugging sessions.
+        this.cleanup();
+    }
+
+    /**
+     * Fetches the brokered service pipe name from C# dev kit, if available.
+     */
+    getBrokeredServicePipeName(): string | undefined {
+        return this._brokeredServicePipeName;
+    }
+
+    /**
+     * No longer tracks any debugging session going forward.
+     */
+    cleanup(): void {
+        this._sessions?.clear();
+        this._sessions = undefined;
+
+        this._onDidStartDebugSession?.dispose();
+        this._onDidTerminateDebugSession?.dispose();
+    }
+}
+
+export const debugSessionTracker = new ProvisionalDebugSessionTracker();

src/main.ts

@@ -57,6 +57,7 @@ import { ServerStateChange } from './lsptoolshost/serverStateChange';
 import { SolutionSnapshotProvider } from './lsptoolshost/services/solutionSnapshotProvider';
 import { RazorTelemetryDownloader } from './razor/razorTelemetryDownloader';
 import { commonOptions, omnisharpOptions, razorOptions } from './shared/options';
+import { debugSessionTracker } from './coreclrDebug/provisionalDebugSessionTracker';
 
 export async function activate(
     context: vscode.ExtensionContext
@@ -335,6 +336,8 @@ export async function activate(
     reporter.sendTelemetryEvent('CSharpActivated', activationProperties);
 
     if (!useOmnisharpServer) {
+        debugSessionTracker.initializeDebugSessionHandlers(context);
+
         tryGetCSharpDevKitExtensionExports(csharpLogObserver);
 
         // If we got here, the server should definitely have been created.
@@ -401,9 +404,9 @@ function tryGetCSharpDevKitExtensionExports(csharpLogObserver: CsharpLoggerObser
                 ]);
 
                 // Notify the vsdbg configuration provider that C# dev kit has been loaded.
-                exports.serverProcessLoaded(async () =>
-                    coreclrdebug.initializeBrokeredServicePipeName(await exports.getBrokeredServiceServerPipeName())
-                );
+                exports.serverProcessLoaded(async () => {
+                    debugSessionTracker.onCsDevKitInitialized(await exports.getBrokeredServiceServerPipeName());
+                });
 
                 vscode.commands.executeCommand('setContext', 'dotnet.debug.serviceBrokerAvailable', true);
             } else {

src/shared/configurationProvider.ts

@@ -5,7 +5,7 @@
 
 import * as vscode from 'vscode';
 import { ParsedEnvironmentFile } from '../coreclrDebug/parsedEnvironmentFile';
-import { getBrokeredServicePipeName } from '../coreclrDebug/activate';
+import { debugSessionTracker } from '../coreclrDebug/provisionalDebugSessionTracker';
 
 import { MessageItem } from '../vscodeAdapter';
 import { CertToolStatusCodes, createSelfSignedCert, hasDotnetDevCertsHttps } from '../utils/dotnetDevCertsHttps';
@@ -66,7 +66,7 @@ export class BaseVsDbgConfigurationProvider implements vscode.DebugConfiguration
             return null;
         }
 
-        const brokeredServicePipeName = getBrokeredServicePipeName();
+        const brokeredServicePipeName = debugSessionTracker.getBrokeredServicePipeName();
         if (brokeredServicePipeName !== undefined) {
             debugConfiguration.brokeredServicePipeName = brokeredServicePipeName;
         }