1283143 - Crash after opening a new tab and switching to private browsing

Status: VERIFIED FIXED

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

Description

[Simon Basca [:SimonB]]

Build: 5.0(8) Nightly
Device: iPad Air 2 (9.3.2)

Steps to reproduce:
1. Launch Firefox
2. Quickly tap on the Private Browosing button
3. Quickly tap on the New Tab button
4. Repeat steps 2 and 3

Actual results:
- The application will crash.

Please see similar issue: https://bugzilla.mozilla.org/show_bug.cgi?id=1270767

Comment 1

[Simon Basca [:SimonB]]

Please note that the issue is reproducible following the steps from the description by tapping on the Private Browsing button and the New Tab button from tabs bar.

Comment 2

[Tyler Lacroix [:tlacroix]]

SimonB: By tabs bar, do you mean the top tabs bar, the tabs tray, or the menu popup?

Comment 3

[Simon Basca [:SimonB]]

Hello, by tabs bar I am referring to the top tabs bar.

Comment 4

[Emily Toop (:fluffyemily)]

I don't seem to be able to click the 2 buttons fast enough on simulator to replicate this and I don't have my iPad at the office today to test on device. Will retest on Friday 22 September when I have access to a suitable device

Comment 5

[Emily Toop (:fluffyemily)]

What a helpful error message (for once, not being facetious)

2016-09-23 14:17:24.924165 Client[310:25885] The behavior of the UICollectionViewFlowLayout is not defined because:
2016-09-23 14:17:24.924754 Client[310:25885] the item height must be less than the height of the UICollectionView minus the section insets top and bottom values, minus the content insets top and bottom values.
2016-09-23 14:17:24.925237 Client[310:25885] The relevant UICollectionViewFlowLayout instance is <Client.TopTabsViewLayout: 0x127e14cd0>, and it is attached to <UICollectionView: 0x128840000; frame = (-10 0; 666 40); gestureRecognizers = <NSArray: 0x1742460f0>; layer = <CALayer: 0x1740392e0>; contentOffset: {0, 0}; contentSize: {2242, 40}> collection view layout: <Client.TopTabsViewLayout: 0x127e14cd0>.
2016-09-23 14:17:24.925684 Client[310:25885] Make a symbolic breakpoint at UICollectionViewFlowLayoutBreakForInvalidSizes to catch this in the debugger.
2016-09-23 14:17:24.938649 Client[310:25885] *** Assertion failure in -[UICollectionViewData indexPathForItemAtGlobalIndex:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit/UIKit-3599.6/UICollectionViewData.m:652

Comment 6

[Emily Toop (:fluffyemily)]

http://stackoverflow.com/a/15454898

"The problem is this: it appears that the indexPath of a supplementary view MUST correspond to the indexPath of an extant cell in the collection. If the supplementary view's index path has no corresponding ordinary cell, the application will crash. I believe that the collection view attempts to retrieve information for a supplementary view's cell for some reason during the update procedure. It crashes when it cannot find one."

Comment 7

[Emily Toop (:fluffyemily)]

The action that causes this is not the rapid tapping of the New Tab after the toggle private data button, but the tapping of Toggle Private Data rapidly after New Tab, causing the new tab to be added in the wrong collection as the privacy status has changed since the new tab was requested. If you wait a second or so between new tab and toggle privacy mode then the crash does not occur.

Comment 8

[Emily Toop (:fluffyemily)]

Attachment: Pull request

Comment 9

[Farhan Patel [:farhan]]

Thanks for fixing this Emily!

master a8d043fc193283fab43a490ae4f9b5fe13c6b83f

Comment 10

[Simon Basca [:SimonB]]

Verifying as fix on Master 1bc8bb71f. 

The toggle private data button is disabled after opening a New Tab.