The static analyser (using Xcode 9.2) was complaining about `gradientComponents` being a variable length array with the possibility of having 0 length. This could occur with `numberOfComponents` keeping the value of 0 if no colours exist. Having a VLA with size 0 causes undefined behaviour.
The change is to bypass rendering the LOTRadialGradientLayer if there are no colours provided, as it doesn't make sense to render anything without a colour, and to presume a default colour may not be the right solution.
* Add support for interactive moves
* Enable drag & drop in collection view example
* Update changelog
* Change the gating logic to match UIKit
* Add a warning when we prevent interactive movement due to async layout
* Reimplement ASRectTable using unordered_map to avoid obscure NSMapTable exception.
The new class is called ASRectMap, which patterns alongside ASIntegerMap in both name and implementation.
After some pretty detailed investigation, including study of open-source reimplementations
of Foundation, the best lead I've found on the NSMapTable exception is that
some NSPointerFunction types are not fully supported. Strangely, the ones being used
do seem to work fine almost all of the time.
The main concern is the Struct memory type, which is not officially re-declared in
NSMapTable, and as such the documentation claims that there may exist some
combinations of NSPointerFunction that are not supported.
Because the exception is occurring frequently enough to be a concern (in the hundreds
to low thousands, though only 50 a day) - I decided to replace NSMapTable entirely
in order to ensure full correctness.
"*** -[NSMapTable initWithKeyPointerFunctions:valuePointerFunctions:capacity:] Requested configuration not supported."
* Fix Xcode project
