Bugfix FXIOS-10315 Fix WebKit exceptions from JS alert completion han…

…dlers (backport #22602) (#22604) Bugfix FXIOS-10315 Fix WebKit exceptions from JS alert completion handlers (#22602) * [FXIOS-10315] Fix redundant completion handler call. * [FXIOS-10315] Fix crash occurring in some scenarios where we might attempt to dequeue and present a JS alert when there was already a presented VC on screen (cherry picked from commit f387704) Co-authored-by: mattreaganmozilla <[email protected]>
mozilla-mobile · Oct 16, 2024 · a3a9741 · a3a9741 · firefoxci-taskcluster · Oct 18, 2024
1 parent 898dfa8
commit a3a9741
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Showing 3 changed files with 11 additions and 8 deletions.
diff --git a/firefox-ios/Client/Frontend/Browser/BrowserPrompts.swift b/firefox-ios/Client/Frontend/Browser/BrowserPrompts.swift
@@ -40,15 +40,15 @@ protocol JSAlertInfo {
 struct MessageAlert: JSAlertInfo {
     let message: String
     let frame: WKFrameInfo
-    let completionHandler: (() -> Void)?
+    let completionHandler: () -> Void
 
     func alertController() -> JSPromptAlertController {
         let alertController = JSPromptAlertController(
             title: titleForJavaScriptPanelInitiatedByFrame(frame),
             message: message,
             preferredStyle: .alert)
         alertController.addAction(UIAlertAction(title: .OKString, style: .default) { _ in
-            completionHandler?()
+            completionHandler()
         })
         alertController.alertInfo = self
         return alertController

diff --git a/...end/Browser/BrowserViewController/Extensions/BrowserViewController+WebViewDelegates.swift b/...end/Browser/BrowserViewController/Extensions/BrowserViewController+WebViewDelegates.swift
@@ -69,7 +69,6 @@ extension BrowserViewController: WKUIDelegate {
             logger.log("Javascript message alert is queued.", level: .info, category: .webview)
 
             promptingTab.queueJavascriptAlertPrompt(messageAlert)
-            completionHandler()
         }
     }
 

diff --git a/firefox-ios/Client/Frontend/Browser/BrowserViewController/Views/BrowserViewController.swift b/firefox-ios/Client/Frontend/Browser/BrowserViewController/Views/BrowserViewController.swift
@@ -1225,11 +1225,12 @@ class BrowserViewController: UIViewController,
     }
 
     fileprivate func showQueuedAlertIfAvailable() {
-        if let queuedAlertInfo = tabManager.selectedTab?.dequeueJavascriptAlertPrompt() {
-            let alertController = queuedAlertInfo.alertController()
-            alertController.delegate = self
-            present(alertController, animated: true, completion: nil)
-        }
+        // See also: similar safety checks in `shouldDisplayJSAlertForWebView`
+        guard presentedViewController == nil else { return }
+        guard let queuedAlertInfo = tabManager.selectedTab?.dequeueJavascriptAlertPrompt() else { return }
+        let alertController = queuedAlertInfo.alertController()
+        alertController.delegate = self
+        present(alertController, animated: true, completion: nil)
     }
 
     func resetBrowserChrome() {
@@ -3937,6 +3938,9 @@ extension BrowserViewController: TabTrayDelegate {
 
 extension BrowserViewController: JSPromptAlertControllerDelegate {
     func promptAlertControllerDidDismiss(_ alertController: JSPromptAlertController) {
+        logger.log("JS prompt was dismissed. Will dequeue next alert.",
+                   level: .info,
+                   category: .webview)
         showQueuedAlertIfAvailable()
     }
 }