1465865 - Crash report: Send Tab with app not running calls addTab before BVC viewDidLoad

Status: VERIFIED FIXED

(Firefox for iOS :: General, defect, P2)

Description

[:garvan]

The line reporting a crash is
```
func tab(_ tab: Tab, didCreateWebView webView: WKWebView) {
        webView.frame = webViewContainer.frame
      ```

webViewContainer is a UIView!, and is initialized in BVC.viewDidLoad(), and a SIGTRAP (as reported here) is indicative of an unwrapped nil.
The stack trace indicates a new tab was created immediately at app start, and BVC.viewDidLoad() would not have run yet.
Here is the annotated stack trace:


Date/Time:           2018-05-30 06:52:44.4262 -0700
Launch Time:         2018-05-30 06:52:43.5272 -0700
OS Version:          iPhone OS 11.4 (15F79)
Baseband Version:    1.04.51
Report Version:      104

Exception Type:  EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000001, 0x0000000102580e38
Termination Signal: Trace/BPT trap: 5
Termination Reason: Namespace SIGNAL, Code 0x5
Terminating Process: exc handler [0]
Triggered by Thread:  0

Thread 0 name:
Thread 0 Crashed:
0   Client                        	0x0000000102580e38 specialized BrowserViewController.tab(_:didCreateWebView:) + 516 (BrowserViewController.swift:1577)
1   Client                        	0x000000010255d9a8 @objc BrowserViewController.tab(_:didCreateWebView:) + 64
2   Client                        	0x0000000102521a94 Tab.createWebview() + 1868 (Tab.swift:0)
3   Client                        	0x0000000102508eac specialized TabManager.configureTab(_:request:afterTab:flushToDisk:zombie:isPopup:) + 2712 (TabManager.swift:355)
4   Client                        	0x0000000102509658 specialized TabManager.addTab(_:configuration:afterTab:flushToDisk:zombie:isPrivate:) + 424 (TabManager.swift:0)
5   Client                        	0x000000010256e344 specialized BrowserViewController.openURLInNewTab(_:isPrivate:isPrivileged:) + 580 (BrowserViewController.swift:0)
6   Client                        	0x000000010242a508 specialized AppDelegate.openURLsInNewTabs(_:) + 1668 (AppDelegate.swift:0)

[Comment: `openURLsInNewTabs` is from send tab.]

7   Client                        	0x0000000102420998 @objc AppDelegate.userNotificationCenter(_:didReceive:withCompletionHandler:) + 104 (AppDelegate.swift:0)
8   Leanplum                      	0x00000001032432d8 -[NSObject(LeanplumExtension) leanplum_userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler:] + 448
9   UIKit                         	0x000000018ae5c2b0 -[UIApplication _handleNonLaunchSpecificActions:forScene:withTransitionContext:completion:] + 2664 (UIApplication.m:9451)
10  UIKit                         	0x000000018ae5a71c -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 4852 (UIApplication.m:2327)
11  UIKit                         	0x000000018ae275e0 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1680 (UIApplication.m:3491)

[COMMENT: the above 3 lines indicate app booting, note also the Launch Time to report time is <1s.]

12  UIKit                         	0x000000018b457b1c __111-[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:]_block_invoke + 784 (_UICanvasLifecycleMonitor.m:175)
13  UIKit                         	0x000000018ae26dd0 +[_UICanvas _enqueuePostSettingUpdateTransactionBlock:] + 160 (_UICanvas.m:591)
14  UIKit                         	0x000000018ae26c6c -[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:] + 240 (_UICanvasLifecycleMonitor.m:153)
15  UIKit                         	0x000000018ae25afc -[__UICanvasLifecycleMonitor_Compatability activateEventsOnly:withContext:completion:] + 724 (_UICanvasLifecycleMonitor.m:229)
16  UIKit                         	0x000000018babb84c __82-[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:]_block_invoke + 296 (_UIApplicationCanvas.m:0)
17  UIKit                         	0x000000018ae251ec -[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:] + 432 (_UIApplicationCanvas.m:156)
18  UIKit                         	0x000000018b8a0ac8 __125-[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:]_block_invoke + 220 (_UICanvasLifecycleSettingsDiffAction.m:211)
19  UIKit                         	0x000000018b9eebf8 _performActionsWithDelayForTransitionContext + 112 (_UICanvasSettingsDiffAction.m:34)
20  UIKit                         	0x000000018ae24c0c -[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:] + 248 (_UICanvasLifecycleSettingsDiffAction.m:182)
21  UIKit                         	0x000000018ae245a8 -[_UICanvas scene:didUpdateWithDiff:transitionContext:completion:] + 368 (_UICanvas.m:517)
22  UIKit                         	0x000000018ae215e0 -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] + 540 (UIApplication.m:3109)
23  UIKit                         	0x000000018ae21330 -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] + 364 (UIApplicationSceneClientAgent.m:41)

Comment 1

[:garvan]

Attachment: Pull request

Comment 2

[:garvan]

landed on master

Comment 3

[:garvan]

Uplifted to 12.x: 75102a1ee

Comment 4

[Catalin Suciu [:csuciu]]

I was able to reproduce the crash on v12.0 (10862). 

On v12.1 (10923) the crash is no longer happening.

Verifying as fixed.