1412897 - Crash in SELUIPasteboardChanged

Status: RESOLVED FIXED

(Firefox for iOS :: General, enhancement, P1)

Description

[:garvan]

Beta 7473, seeing crash report of infinite loop in SELUIPasteboardChanged:


```
#23	(null) in @objc ClipboardBarDisplayHandler.SELUIPasteboardChanged() at Client/Frontend/Browser/ClipboardBarDisplayHandler.swift:46
#24	(null) in __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ ()
#25	(null) in _CFXRegistrationPost ()
#26	(null) in ___CFXNotificationPost_block_invoke ()
#27	(null) in -[_CFXNotificationRegistrar find:object:observer:enumerator:] ()
#28	(null) in _CFXNotificationPost ()
#29	(null) in -[NSNotificationCenter postNotificationName:object:userInfo:] ()
#30	(null) in _sendPasteboardChangedNotification ()
#31	(null) in +[_UIConcretePasteboard _pasteboardNamed:createIfNotFound:] ()
#32	(null) in @objc ClipboardBarDisplayHandler.SELUIPasteboardChanged() at Client/Frontend/Browser/ClipboardBarDisplayHandler.swift:46

```

Comment 1

[:garvan]

The first line of `SELUIPasteboardChanged()` calls `UIPasteboard.general` which triggers a pasteboard changed notification.
Easy fixes are:
1) Add re-entrancy guard, and/or
2) Remove listener when function is hit, re-add when done

Comment 2

[:garvan]

See also: https://bugzilla.mozilla.org/show_bug.cgi?id=1405604

Comment 3

[:garvan]

Attachment: Pull request

I couldn't repro the crash; I am not able to trigger a notification when accessing UIPasteboard.general.
I can see in the assembly that UIPasteboard accessor function is returning before hitting the notification; I assume that is because `general` already existed -I am "assuming" because I am not trying to figure out the assembly there :).

Comment 4

[Justin D'Arcangelo [:justindarc]]

Landed on master:

https://github.com/mozilla-mobile/firefox-ios/commit/952a2dfd02c030793d3c256ded460aa75684db97

Landed on v10.x:

https://github.com/mozilla-mobile/firefox-ios/commit/0e6d096248cf6b25ba8fe11974908a383c619d6a