App crashing randomly - Not possible to remove variable

Question

BibinAlex OP

Created Feb ’21

Replies 10

Boosts 0

Views 6.3k

Participants 12

** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Not possible to remove variable: 400: <unknown var (bug!) with engine as delegate:0x283c8ed40>{id: 33112} colIndex:32 from engine <NSISEngine: 0x129248130>{ delegate:0x12934eaa0

EngineVars:
0: objective{id: 33102} rowIndex:0
1: UIImageView:0x12924ec90.Height{id: 32592} rowIndex:1073741824
2: 0x280a04be0.marker{id: 32591} colIndex:1073741825
3: UIImageView:0x12924ec90.Width{id: 32807} rowIndex:1
4: 0x280dc35a0.posErrorMarker{id: 32871} colIndex:1
5: 0x280dc35a0.negError{id: 32872} rowIndex:88
6: 0x280dc3d80.posErrorMarker{id: 32873} colIndex:1073741826
7: 0x280dc3d80.negError{id: 32874} rowIndex:1073741825
8: UIImageView:0x129353f00.Width{id: 32594} rowIndex:2
9: 0x280979d60.marker{id: 32593} colIndex:3
10: 0x280dc1e60.posErrorMarker{id: 32875} colIndex:4
11: 0x280dc1e60.negError{id: 32876} rowIndex:3
12: UIImageView:0x129353f00.Height{id: 32822} rowIndex:1073741826
13: 0x280dc39c0.posErrorMarker{id: 32877} colIndex:1073741827
14: 0x280dc39c0.negError{id: 32878} rowIndex:1073741898
15: UIButton:0x1293540d0.Width{id: 32817} rowIndex:4
16: 0x280dc2040.posErrorMarker{id: 32879} rowIndex:93
17: 0x280dc2040.negError{id: 32880} colIndex:6
18: UIButton:0x1293540d0.Height{id: 32820} rowIndex:1073741827
19: 0x280dc3de0.posErrorMarker{id: 32881} rowIndex:96
20: 0x280dc3de0.negError{id: 32882} colIndex:1073741830
21: UILabel:0x129353300.Width{id: 32811} rowIndex:5
22: 0x280dc3e40.posErrorMarker{id: 32883} colIndex:44
23: 0x280dc3e40.negError{id: 32884} rowIndex:90
24: UILabel:0x129353300.Height{id: 32842} colIndex:1073741828
25: 0x280dc27c0.posErrorMarker{id: 32885} colIndex:1073741831
26: 0x280dc27c0.negError{id: 32886} rowIndex:1073741828
27: UILabel:0x129353c90.Width{id: 32840} rowIndex:6
28: 0x280dc1da0.posErrorMarker{id: 32887} colIndex:9
29: 0x280dc1da0.negError{id: 32888} rowIndex:97
30: UILabel:0x129353c90.Height{id: 32829} colIndex:1073741832
31: 0x280dc31e0.posErrorMarker{id: 32889} colIndex:1073741833
32: 0x280dc31e0.negError{id: 32890} rowIndex:1073741900
33: UIImageView:0x12934e490.Width{id: 32596} rowIndex:1073741905
34: UIImageView:0x12934e490.Height{id: 32597} colIndex:1073741844
35: 0x280963a70.marker{id: 32595} colIndex:11
36: 0x280dc2ee0.posErrorMarker{id: 32891} colIndex:12
37: 0x280dc2ee0.negError{id: 32892} rowIndex:8
38: 0x280dc1d40.posErrorMarker{id: 32893} colIndex:1073741835
39: 0x280dc1d40.negError{id: 32894} rowIndex:1073741830
40: UIButton:0x1293543b0.Width{id: 32832} rowIndex:9
41: 0x280dc1440.posErrorMarker{id: 32895} colIndex:0
42: 0x280dc1440.negError{id: 32896} rowIndex:1073741845
43: UIButton:0x1293543b0.Height{id: 32827} rowIndex:1073741831
44: 0x280dc3840.posErrorMarker{id: 32897} colIndex:1073741836
45: 0x280dc3840.negError{id: 32898} rowIndex:1073741829
46: UILabel:0x129353a20.Width{id: 32848} rowIndex:10

and another thousand or so lines.

this crash occurs after I change the language and open the workout page to start a workout immediately, and sometimes on the second time, I open the workout page.

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Answer 1

Claude31 OP

Feb ’21

I change the language and open the workout page to start a workout immediately

Could you explain more the context ?
Do you know what NSISEngine is ?

0

Answer 2

BibinAlex OP

Feb ’21

@Claude31 from what I know NSISEngine optimizes constraints and manages autolayout.

0

Answer 3

Apple Staff OP

Apple

Feb ’21

What is "the workout page"? We would need a full crash log to be able to investigate further.

0

Answer 4

DTS Engineer OP

Apple

Feb ’21

We would need a full crash log to be able to investigate further.

Quite.

When you post your crash report, use the text attachment feature (the paperclip icon) to avoid clogging up the timeline.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

0

Answer 5

dbeltram OP

Apr ’21

I got a similar crash recently.
My case is a UIStackView contained in a UITableViewCell.
When binding data to the cell, since the content of the UIStackView is dynamic, I remove all the arrangedSubviews in the stack before populating it again with the new content.

For every arranged subview this following block is executed:

Code Block stack.removeArrangedSubview(subview)
subview.removeFromSuperview()

Crash is indicated to occur on the last of the above lines.
Note that this crash hit randomly, i.e. it cannot be systematically reproduced every time.

Attached is the crash log.
Hope this could help.

Crash log

1

Answer 6

Vin_ OP

Jul ’21

Hi @dbeltram, Did you found fix for mentioned issue. I am facing same issue and crashing at

subview.removeFromSuperview().

0

Answer 7

pravintate_2612 OP

Aug ’21

Is any one found solution for this crash. Facing same issue on 14.6 and onward versions but not able to reproduce. Used stackview and inside that used imageView and label when we again setup removing arragedView and remove their constraints and then remove stackView and add it again. Crash log showing removeFromSuperView stack view crashing.

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Answer 8

AlaaHallq OP

Sep ’21

I had a similar issue, resolved it just yesterday. the solution to it was to remove the following call to

UIView.appearance().semanticContentAttribute = isRTL ? .forceRightToLeft : .forceLeftToRight

/*
  where `isRTL` is a global computed variable that gets the UI direction of the current `Locale` that I set when the user changes the language.
*/

whenever the ui language is changed by the user, and to enforce using the correct layout direction I was Swizzling the UIApplication.userInterfaceLayoutDirection to return the proper UI direction according to the selected language.

Note: I had a crash just once in over 100 tests, where the other +99 tests the issue was a delay in viewing an already created ViewController vc either by otherVC.present(vc) it, nav.push(vc) it, nav.set([vc]), or nav.pop to vc, meaning if the that vc is just created will not cause any delay but if it was already created and presented before, there will be a delay between viewWillAppear and viewDidAppear for ~200mSec x n times UI direction changes

200mSec is relative to the UI complexity of vc.

In that single crash this is the message I got:

Thread 1: "Not possible to remove variable: 2247: <unknown var (bug!) with engine as delegate:0x600001c1b6c0>{id: 47987} colIndex:0 from engine <NSISEngine: 0x14dc8fae0>{ delegate:0x14dc99e20
EngineVars:
      0: objective{id: 42093} rowIndex:0
      1: <bgImage>.Width{id: 41414} rowIndex:1
      2: 0x6000020aaee0.posErrorMarker{id: 41958} colIndex:1
      3: 0x6000020aaee0.negError{id: 41959} rowIndex:456
      4: <bgImage>.Height{id: 41420} rowIndex:1073741824
      5: 0x6000020a8ae0.posErrorMarker{id: 41960} colIndex:1073741825
      6: 0x6000020a8ae0.negError{id: 41961} rowIndex:1073742291
      7: UIImageView:0x14dc502c0.Height{id: 41428} rowIndex:1073741825
      8: 0x6000024589b0.marker{id: 41427} colIndex:1073741828
      9: UIImageView:0x14dc502c0.Width{id: 41426} colIndex:590
     10: 0x6000020ab180.posErrorMarker{id: 41962} colIndex:3
     11: 0x6000020ab180.negError{id: 41963} rowIndex:3
     12: 0x6000020a8ea0.posErrorMarker{id: 41964} colIndex:1073741832
     13: 0x6000020a8ea0.negError{id: 41965} rowIndex:1073741826
     14: 0x600002428f50:UISV-amb"

0

Answer 9

vijayrad OP

Jul ’23

When I use code

UIView.appearance().semanticContentAttribute = isRTL ? .forceRightToLeft : .forceLeftToRight

app is crashing randomly.

0

Answer 10

samcortez OP

Apr ’24

Hello! I was experiencing a similar crash as everyone else in the thread as well, in which I also have an UIStackView inside a reusable cell. For us we noticed that it could be tracked back to a rogue UIStackView with the distribution set to .fillProportionally.

This seems to cause the view to generate layout inconsistencies that every now and then would result in an invalid state that would crash when trying to remove the subviews. Simply using a different distribution (while keeping same layout) was enough to prevent the crash from happening. I have now run about 10000 tests and all were successful.

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