Preserve terminal visibility across background session restart

Author: Copilot

src/process.ts

@@ -238,6 +238,10 @@ export class PowerShellProcess {
         this.consoleTerminal?.show(preserveFocus);
     }
 
+    public isTerminalActive(): boolean {
+        return this.consoleTerminal === vscode.window.activeTerminal;
+    }
+
     public dispose(): void {
         this.logger.writeDebug(
             `Disposing PowerShell process with PID: ${this.pid}`,

src/session.ts

@@ -347,6 +347,11 @@ export class SessionManager implements Middleware {
 
     private async restartSession(exeNameOverride?: string): Promise<void> {
         this.logger.write("Restarting session...");
+        const shouldRevealTerminalAfterRestart =
+            this.languageServerProcess?.isTerminalActive() === true &&
+            vscode.workspace
+                .getConfiguration("powershell.integratedConsole")
+                .get<boolean>("startInBackground") === true;
         await this.stop();
 
         if (exeNameOverride) {
@@ -361,6 +366,9 @@ export class SessionManager implements Middleware {
         }
 
         await this.start();
+        if (shouldRevealTerminalAfterRestart) {
+            this.languageServerProcess?.showTerminal(true);
+        }
     }
 
     /** In Development mode, write the PID to a file where the parent session can find it, to attach the dotnet debugger. */

test/core/session.test.ts

@@ -6,6 +6,7 @@ import * as assert from "assert";
 import Sinon from "sinon";
 import * as vscode from "vscode";
 import type { DocumentSelector } from "vscode-languageclient";
+import { PowerShellProcess } from "../../src/process";
 import {
     type IPowerShellVersionDetails,
     SessionManager,
@@ -200,6 +201,89 @@ describe("SessionManager.getVersionDetails", () => {
     });
 });
 
+describe("SessionManager.restartSession", () => {
+    afterEach(() => {
+        Sinon.restore();
+    });
+
+    it("re-shows the terminal after restart when it was active in background mode", async () => {
+        const manager = makeManager();
+        const oldProcess = stubInterface<PowerShellProcess>({
+            isTerminalActive: () => true,
+        });
+        const showTerminal = Sinon.spy();
+        const newProcess = stubInterface<PowerShellProcess>({
+            showTerminal,
+        });
+        (
+            manager as unknown as { languageServerProcess: PowerShellProcess }
+        ).languageServerProcess = oldProcess;
+
+        Sinon.stub(vscode.workspace, "getConfiguration").returns(
+            stubInterface<vscode.WorkspaceConfiguration>({
+                get: <T>(_section: string): T => true as T,
+            }),
+        );
+        Sinon.stub(manager as unknown as { stop(): Promise<void> }, "stop")
+            .resolves();
+        Sinon.stub(manager as unknown as { start(): Promise<void> }, "start")
+            .callsFake(async () => {
+                (
+                    manager as unknown as {
+                        languageServerProcess: PowerShellProcess;
+                    }
+                ).languageServerProcess = newProcess;
+            });
+
+        await (
+            manager as unknown as {
+                restartSession(): Promise<void>;
+            }
+        ).restartSession();
+
+        assert.strictEqual(showTerminal.callCount, 1);
+        assert.deepStrictEqual(showTerminal.firstCall.args, [true]);
+    });
+
+    it("keeps the terminal hidden after restart when it was not active in background mode", async () => {
+        const manager = makeManager();
+        const oldProcess = stubInterface<PowerShellProcess>({
+            isTerminalActive: () => false,
+        });
+        const showTerminal = Sinon.spy();
+        const newProcess = stubInterface<PowerShellProcess>({
+            showTerminal,
+        });
+        (
+            manager as unknown as { languageServerProcess: PowerShellProcess }
+        ).languageServerProcess = oldProcess;
+
+        Sinon.stub(vscode.workspace, "getConfiguration").returns(
+            stubInterface<vscode.WorkspaceConfiguration>({
+                get: <T>(_section: string): T => true as T,
+            }),
+        );
+        Sinon.stub(manager as unknown as { stop(): Promise<void> }, "stop")
+            .resolves();
+        Sinon.stub(manager as unknown as { start(): Promise<void> }, "start")
+            .callsFake(async () => {
+                (
+                    manager as unknown as {
+                        languageServerProcess: PowerShellProcess;
+                    }
+                ).languageServerProcess = newProcess;
+            });
+
+        await (
+            manager as unknown as {
+                restartSession(): Promise<void>;
+            }
+        ).restartSession();
+
+        assert.strictEqual(showTerminal.callCount, 0);
+    });
+});
+
 function makeManager(): SessionManager {
     Sinon.stub(vscode.commands, "registerCommand").returns(disposableStub());
     Sinon.stub(vscode.workspace, "onDidChangeConfiguration").returns(