Keyboard autolayout constraint violations on iPad with iOS 11 and 12

Originator:ahruman
Number:rdar://45729580 Date Originated:2018-11-01
Status:Open Resolved:
Product:iOS SDK; Area: Keyboard Product Version:
Classification:Other Bug Reproducible:Always
 
Summary:
Since iOS 11, switching between text fields on an iPad causes an autolayout constraint violation in the keyboard view hierarchy.

Steps to Reproduce:
* Run the attached project on an iPad simulator
* Select the text field by User Name
* Select the test field by Password

Expected Results:
No logging or breakpoints hit

Actual Results:
The project’s shared breakpoint in UIViewAlertForUnsatisfiableConstraints is hit, and a message is logged about unsatisfiable constraints. (Example message included in attachment)

Version/Build:
Verified on simulators for iOS 11.0.1, 11.4, and 12.1. Cannot reproduce in iOS 10.3.1. Cannot reproduce on iPhone.

Configuration:

Comments

Example output

[LayoutConstraints] Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) ( "", "<NSLayoutConstraint:0x6000015820d0 V:|-(0)-_UIButtonBarStackView:0x7fa3ee8035e0>", "", "", "", "<NSLayoutConstraint:0x6000015a5770 'UIView-topMargin-guide-constraint' V:|-(10)-UILayoutGuide:0x600000fa0c40'UIViewLayoutMarginsGuide'>" )

Will attempt to recover by breaking constraint

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in may also be helpful.

By ahruman at Nov. 1, 2018, 3:09 p.m. (reply...)

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