UILayoutPriorityDefaultLow in iOS 11.2 is invalid!

[holyhan]

New Issue Checklist

In iOS 11.2, to run Masonry's demo, I get a constraint error.

Issue Info

Info	Value
Platform	e.g. ios
Platform Version	e.g. 11.2
Masonry Version	e.g. 1.1.0
Integration Method	e.g. cocoapods

Issue Description

In MASExampleUpdateView class, followed code: [self.growingButton updateConstraints:^(MASConstraintMaker *make) { make.center.equalTo(self); make.width.equalTo(@(self.buttonSize.width)).priorityLow(); make.height.equalTo(@(self.buttonSize.height)).priorityLow(); make.width.lessThanOrEqualTo(self); make.height.lessThanOrEqualTo(self); }]; In this block, priorityLow() method make self.growingButton's both width and height constraint priority to @1000, then click button to update constraint is invalid.

[holyhan]

this issue is caused by UIButton's contentSize, which have default width and height priority(@250), you reset this button's width and height to priorityLow, so that both width and height constraint ambiguity.