Skip to content

Fix browser panel lifecycle after WebContent process termination #892

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
lawrencecchen merged 3 commits into from
Mar 5, 2026
Merged

Fix browser panel lifecycle after WebContent process termination #892

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
5b730d8
Fix browser panel webview lifecycle after web content crashes
lawrencecchen Mar 4, 2026
d2171c1
Fix BrowserPanel observer lifecycle during webview replacement
lawrencecchen Mar 5, 2026
8e01acf
Fix WebKit termination delegate and harden lifecycle regression check
lawrencecchen Mar 5, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
164 changes: 125 additions & 39 deletions Sources/Panels/BrowserPanel.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1389,7 +1389,11 @@ final class BrowserPanel: Panel, ObservableObject {
private(set) var workspaceId: UUID

/// The underlying web view
let webView: WKWebView
private(set) var webView: WKWebView

/// Monotonic identity for the current WKWebView instance.
/// Incremented whenever we replace the underlying WKWebView after a process crash.
@Published private(set) var webViewInstanceID: UUID = UUID()

/// Prevent the omnibar from auto-focusing for a short window after explicit programmatic focus.
/// This avoids races where SwiftUI focus state steals first responder back from WebKit.
Expand Down Expand Up @@ -1477,8 +1481,7 @@ final class BrowserPanel: Panel, ObservableObject {
}
}
private var searchNeedleCancellable: AnyCancellable?

private var cancellables = Set<AnyCancellable>()
private var webViewCancellables = Set<AnyCancellable>()
private var navigationDelegate: BrowserNavigationDelegate?
private var uiDelegate: BrowserUIDelegate?
private var downloadDelegate: BrowserDownloadDelegate?
Expand All @@ -1499,7 +1502,7 @@ final class BrowserPanel: Panel, ObservableObject {
private let pageZoomStep: CGFloat = 0.1
private var insecureHTTPBypassHostOnce: String?
private var insecureHTTPAlertFactory: () -> NSAlert
private var insecureHTTPAlertWindowProvider: () -> NSWindow?
private var insecureHTTPAlertWindowProvider: () -> NSWindow? = { NSApp.keyWindow ?? NSApp.mainWindow }
// Persist user intent across WebKit detach/reattach churn (split/layout updates).
private var preferredDeveloperToolsVisible: Bool = false
private var forceDeveloperToolsRefreshOnNextAttach: Bool = false
Expand Down Expand Up @@ -1527,13 +1530,7 @@ final class BrowserPanel: Panel, ObservableObject {
false
}

init(workspaceId: UUID, initialURL: URL? = nil, bypassInsecureHTTPHostOnce: String? = nil) {
self.id = UUID()
self.workspaceId = workspaceId
self.insecureHTTPBypassHostOnce = BrowserInsecureHTTPSettings.normalizeHost(bypassInsecureHTTPHostOnce ?? "")
self.browserThemeMode = BrowserThemeSettings.mode()

// Configure web view
private static func makeWebView() -> CmuxWebView {
let config = WKWebViewConfiguration()
config.processPool = BrowserPanel.sharedProcessPool
// Ensure browser cookies/storage persist across navigations and launches.
Expand All @@ -1554,27 +1551,41 @@ final class BrowserPanel: Panel, ObservableObject {
)
)

// Set up web view
let webView = CmuxWebView(frame: .zero, configuration: config)
webView.allowsBackForwardNavigationGestures = true

// Required for Web Inspector support on recent WebKit SDKs.
if #available(macOS 13.3, *) {
webView.isInspectable = true
}

// Match the empty-page background to the terminal theme so newly-created browsers
// don't flash white before content loads.
webView.underPageBackgroundColor = GhosttyBackgroundTheme.currentColor()

// Always present as Safari.
webView.customUserAgent = BrowserUserAgentSettings.safariUserAgent
return webView
}

private func bindWebView(_ webView: CmuxWebView) {
webView.onContextMenuDownloadStateChanged = { [weak self] downloading in
if downloading {
self?.beginDownloadActivity()
} else {
self?.endDownloadActivity()
}
}
webView.navigationDelegate = navigationDelegate
webView.uiDelegate = uiDelegate
setupObservers(for: webView)
}

init(workspaceId: UUID, initialURL: URL? = nil, bypassInsecureHTTPHostOnce: String? = nil) {
self.id = UUID()
self.workspaceId = workspaceId
self.insecureHTTPBypassHostOnce = BrowserInsecureHTTPSettings.normalizeHost(bypassInsecureHTTPHostOnce ?? "")
self.browserThemeMode = BrowserThemeSettings.mode()

let webView = Self.makeWebView()
self.webView = webView
self.insecureHTTPAlertFactory = { NSAlert() }
self.insecureHTTPAlertWindowProvider = { [weak webView] in
webView?.window ?? NSApp.keyWindow ?? NSApp.mainWindow
}

// Set up navigation delegate
let navDelegate = BrowserNavigationDelegate()
Expand Down Expand Up @@ -1612,6 +1623,9 @@ final class BrowserPanel: Panel, ObservableObject {
navDelegate.handleBlockedInsecureHTTPNavigation = { [weak self] request, intent in
self?.presentInsecureHTTPAlert(for: request, intent: intent, recordTypedNavigation: false)
}
navDelegate.didTerminateWebContentProcess = { [weak self] webView in
self?.replaceWebViewAfterContentProcessTermination(for: webView)
}
// Set up download delegate for navigation-based downloads.
// Downloads save to a temp file synchronously (no NSSavePanel during WebKit
// callbacks), then show NSSavePanel after the download completes.
Expand All @@ -1627,14 +1641,6 @@ final class BrowserPanel: Panel, ObservableObject {
}
navDelegate.downloadDelegate = dlDelegate
self.downloadDelegate = dlDelegate
webView.onContextMenuDownloadStateChanged = { [weak self] downloading in
if downloading {
self?.beginDownloadActivity()
} else {
self?.endDownloadActivity()
}
}
webView.navigationDelegate = navDelegate
self.navigationDelegate = navDelegate

// Set up UI delegate (handles cmd+click, target=_blank, and context menu)
Expand All @@ -1646,12 +1652,13 @@ final class BrowserPanel: Panel, ObservableObject {
browserUIDelegate.requestNavigation = { [weak self] request, intent in
self?.requestNavigation(request, intent: intent)
}
webView.uiDelegate = browserUIDelegate
self.uiDelegate = browserUIDelegate

// Observe web view properties
setupObservers()
bindWebView(webView)
applyBrowserThemeModeIfNeeded()
insecureHTTPAlertWindowProvider = { [weak self] in
self?.webView.window ?? NSApp.keyWindow ?? NSApp.mainWindow
}

// Navigate to initial URL if provided
if let url = initialURL {
Expand Down Expand Up @@ -1729,7 +1736,7 @@ final class BrowserPanel: Panel, ObservableObject {
refreshNavigationAvailability()
}

private func setupObservers() {
private func setupObservers(for webView: WKWebView) {
Comment thread
cubic-dev-ai[bot] marked this conversation as resolved.
// URL changes
let urlObserver = webView.observe(\.url, options: [.new]) { [weak self] webView, _ in
Task { @MainActor in
Expand Down Expand Up @@ -1792,9 +1799,85 @@ final class BrowserPanel: Panel, ObservableObject {
guard let self else { return }
self.webView.underPageBackgroundColor = GhosttyBackgroundTheme.color(from: notification)
}
.store(in: &cancellables)
.store(in: &webViewCancellables)
}

private func replaceWebViewAfterContentProcessTermination(for terminatedWebView: WKWebView) {
guard terminatedWebView === webView else { return }

let wasRenderable = shouldRenderWebView
let restoreURL = terminatedWebView.url ?? currentURL
let restoreURLString = restoreURL?.absoluteString
let shouldRestoreURL = wasRenderable && restoreURLString != nil && restoreURLString != blankURLString
let history = sessionNavigationHistorySnapshot()
let historyCurrentURL = preferredURLStringForOmnibar()
let desiredZoom = max(minPageZoom, min(maxPageZoom, terminatedWebView.pageZoom))
let restoreDevTools = preferredDeveloperToolsVisible

#if DEBUG
dlog(
"browser.webview.replace.begin panel=\(id.uuidString.prefix(5)) " +
"renderable=\(wasRenderable ? 1 : 0) restoreURL=\(restoreURLString ?? "nil") " +
"restoreHistoryBack=\(history.backHistoryURLStrings.count) " +
"restoreHistoryForward=\(history.forwardHistoryURLStrings.count)"
)
#endif

webViewObservers.removeAll()
webViewCancellables.removeAll()
BrowserWindowPortalRegistry.detach(webView: terminatedWebView)

@chatgpt-codex-connector chatgpt-codex-connector Bot Mar 5, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

P1 Badge Resign first responder before detaching crashed WebView

In replaceWebViewAfterContentProcessTermination, the old terminatedWebView is detached immediately, but this recovery path never clears first responder first. If the crash happens while the browser pane is focused (common during typing/clicking), detaching a responder-chain WKWebView can leave a stale responder or trigger the same WebKit reparenting crash that other teardown paths already guard against in WebViewRepresentable.dismantleNSView via window.makeFirstResponder(nil). Please resign first responder for the terminating view/window before BrowserWindowPortalRegistry.detach(...).

Useful? React with 👍 / 👎.

terminatedWebView.stopLoading()
terminatedWebView.navigationDelegate = nil
terminatedWebView.uiDelegate = nil
if let terminatedCmuxWebView = terminatedWebView as? CmuxWebView {
terminatedCmuxWebView.onContextMenuDownloadStateChanged = nil
}

let replacement = Self.makeWebView()
replacement.pageZoom = desiredZoom
webView = replacement
webViewInstanceID = UUID()
shouldRenderWebView = wasRenderable

bindWebView(replacement)

@chatgpt-codex-connector chatgpt-codex-connector Bot Mar 5, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

P2 Badge Cancel prior theme observers when swapping WKWebView

When WebContent terminates, replaceWebViewAfterContentProcessTermination rebinds via bindWebView(replacement), which calls setupObservers(for:) and adds another .ghosttyDefaultBackgroundDidChange subscription to cancellables. This path clears webViewObservers but never clears/reuses cancellables, so repeated process crashes accumulate stale subscriptions and make each background-theme notification run multiple times, causing unbounded memory/work growth over time.

Useful? React with 👍 / 👎.

@chatgpt-codex-connector chatgpt-codex-connector Bot Mar 5, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

P2 Badge Reapply browser theme to replacement web view

The crash-recovery path builds a new WKWebView and binds delegates/observers, but it never reapplies the user-selected browser theme mode. makeWebView() leaves appearance at system defaults, so after a WebContent termination a forced light/dark setting is lost until a later successful navigation triggers didFinish (and in some failure flows it may stay wrong longer). Apply applyBrowserThemeModeIfNeeded() immediately after rebinding the replacement view to preserve theme consistency through recovery.

Useful? React with 👍 / 👎.


if !history.backHistoryURLStrings.isEmpty || !history.forwardHistoryURLStrings.isEmpty {
restoreSessionNavigationHistory(
backHistoryURLStrings: history.backHistoryURLStrings,
forwardHistoryURLStrings: history.forwardHistoryURLStrings,
currentURLString: historyCurrentURL
)
}

if shouldRestoreURL, let restoreURL {
navigateWithoutInsecureHTTPPrompt(
to: restoreURL,
recordTypedNavigation: false,
preserveRestoredSessionHistory: true
)
} else {
refreshNavigationAvailability()
}

if restoreDevTools {
requestDeveloperToolsRefreshAfterNextAttach(reason: "webcontent_process_terminated")
}

#if DEBUG
dlog(
"browser.webview.replace.end panel=\(id.uuidString.prefix(5)) " +
"instance=\(webViewInstanceID.uuidString.prefix(6)) " +
"restoreURL=\(restoreURLString ?? "nil") shouldRestore=\(shouldRestoreURL ? 1 : 0)"
)
#endif
}

#if DEBUG
func debugSimulateWebContentProcessTermination() {
replaceWebViewAfterContentProcessTermination(for: webView)
}
#endif

// MARK: - Panel Protocol

func focus() {
Expand Down Expand Up @@ -1835,7 +1918,7 @@ final class BrowserPanel: Panel, ObservableObject {
navigationDelegate = nil
uiDelegate = nil
webViewObservers.removeAll()
cancellables.removeAll()
webViewCancellables.removeAll()
faviconTask?.cancel()
faviconTask = nil
}
Expand Down Expand Up @@ -2191,7 +2274,7 @@ final class BrowserPanel: Panel, ObservableObject {
BrowserWindowPortalRegistry.detach(webView: webView)
}
webViewObservers.removeAll()
cancellables.removeAll()
webViewCancellables.removeAll()
}
}

Expand Down Expand Up @@ -2871,8 +2954,8 @@ extension BrowserPanel {

func resetInsecureHTTPAlertHooksForTesting() {
insecureHTTPAlertFactory = { NSAlert() }
insecureHTTPAlertWindowProvider = { [weak weakWebView = self.webView] in
weakWebView?.window ?? NSApp.keyWindow ?? NSApp.mainWindow
insecureHTTPAlertWindowProvider = { [weak self] in
self?.webView.window ?? NSApp.keyWindow ?? NSApp.mainWindow
}
}

Expand Down Expand Up @@ -3155,6 +3238,7 @@ func browserNavigationShouldOpenInNewTab(
private class BrowserNavigationDelegate: NSObject, WKNavigationDelegate {
var didFinish: ((WKWebView) -> Void)?
var didFailNavigation: ((WKWebView, String) -> Void)?
var didTerminateWebContentProcess: ((WKWebView) -> Void)?
var openInNewTab: ((URL) -> Void)?
var shouldBlockInsecureHTTPNavigation: ((URL) -> Bool)?
var handleBlockedInsecureHTTPNavigation: ((URLRequest, BrowserInsecureHTTPNavigationIntent) -> Void)?
Expand Down Expand Up @@ -3221,9 +3305,11 @@ private class BrowserNavigationDelegate: NSObject, WKNavigationDelegate {
completionHandler(.performDefaultHandling, nil)
}

func webView(_ webView: WKWebView, webContentProcessDidTerminate: WKWebView) {
NSLog("BrowserPanel web content process terminated, reloading")
webView.reload()
func webViewWebContentProcessDidTerminate(_ webView: WKWebView) {
#if DEBUG
dlog("browser.webcontent.terminated panel=\(String(describing: self))")
#endif
didTerminateWebContentProcess?(webView)
}

private func loadErrorPage(in webView: WKWebView, failedURL: String, error: NSError) {
Expand Down
Loading