"Webview is disposed" error notification on switching to a branch (microsoft#2828)

Fixes microsoft#2444

Author: alexr00

src/common/webview.ts

@@ -101,6 +101,30 @@ export class WebviewViewBase extends WebviewBase {
 	public readonly viewType: string;
 	protected _view?: vscode.WebviewView;
 
+	constructor(
+		protected readonly _extensionUri: vscode.Uri) {
+		super();
+	}
+
+	protected resolveWebviewView(
+		webviewView: vscode.WebviewView,
+		_context: vscode.WebviewViewResolveContext,
+		_token: vscode.CancellationToken) {
+		this._view = webviewView;
+		this._webview = webviewView.webview;
+		super.initialize();
+		webviewView.webview.options = {
+			// Allow scripts in the webview
+			enableScripts: true,
+
+			localResourceRoots: [this._extensionUri],
+		};
+		this._disposables.push(this._view.onDidDispose(() => {
+			this._webview = undefined;
+			this._view = undefined;
+		}));
+	}
+
 	public show() {
 		if (this._view) {
 			this._view.show();

src/github/activityBarViewProvider.ts

@@ -20,11 +20,11 @@ export class PullRequestViewProvider extends WebviewViewBase implements vscode.W
 	private _existingReviewers: ReviewState[] = [];
 
 	constructor(
-		private readonly _extensionUri: vscode.Uri,
+		extensionUri: vscode.Uri,
 		private readonly _folderRepositoryManager: FolderRepositoryManager,
 		private _item: PullRequestModel,
 	) {
-		super();
+		super(extensionUri);
 
 		this.registerFolderRepositoryListener();
 
@@ -68,17 +68,7 @@ export class PullRequestViewProvider extends WebviewViewBase implements vscode.W
 		_context: vscode.WebviewViewResolveContext,
 		_token: vscode.CancellationToken,
 	) {
-		this._view = webviewView;
-		this._webview = webviewView.webview;
-		super.initialize();
-
-		webviewView.webview.options = {
-			// Allow scripts in the webview
-			enableScripts: true,
-
-			localResourceRoots: [this._extensionUri],
-		};
-
+		super.resolveWebviewView(webviewView, _context, _token);
 		webviewView.webview.html = this._getHtmlForWebview();
 
 		this.updatePullRequest(this._item);

src/github/createPRViewProvider.ts

@@ -45,12 +45,12 @@ export class CreatePullRequestViewProvider extends WebviewViewBase implements vs
 	private _firstLoad: boolean = true;
 
 	constructor(
-		private readonly _extensionUri: vscode.Uri,
+		extensionUri: vscode.Uri,
 		private readonly _folderRepositoryManager: FolderRepositoryManager,
 		private readonly _pullRequestDefaults: PullRequestDefaults,
 		compareBranch: Branch,
 	) {
-		super();
+		super(extensionUri);
 
 		this._compareBranch = compareBranch;
 	}
@@ -60,16 +60,7 @@ export class CreatePullRequestViewProvider extends WebviewViewBase implements vs
 		_context: vscode.WebviewViewResolveContext,
 		_token: vscode.CancellationToken,
 	) {
-		this._view = webviewView;
-		this._webview = webviewView.webview;
-		super.initialize();
-		webviewView.webview.options = {
-			// Allow scripts in the webview
-			enableScripts: true,
-
-			localResourceRoots: [this._extensionUri],
-		};
-
+		super.resolveWebviewView(webviewView, _context, _token);
 		webviewView.webview.html = this._getHtmlForWebview();
 
 		if (this._firstLoad) {

src/github/issueOverview.ts

@@ -40,8 +40,8 @@ export class IssueOverviewPanel<TItem extends IssueModel = IssueModel> extends W
 		const activeColumn = toTheSide
 			? vscode.ViewColumn.Beside
 			: vscode.window.activeTextEditor
-			? vscode.window.activeTextEditor.viewColumn
-			: vscode.ViewColumn.One;
+				? vscode.window.activeTextEditor.viewColumn
+				: vscode.ViewColumn.One;
 
 		// If we already have a panel, show it.
 		// Otherwise, create a new panel.
@@ -364,6 +364,7 @@ export class IssueOverviewPanel<TItem extends IssueModel = IssueModel> extends W
 
 		// Clean up our resources
 		this._panel.dispose();
+		this._webview = undefined;
 
 		while (this._disposables.length) {
 			const x = this._disposables.pop();