Open Radar

 
Summary:
Setting UITextView's `text` property does not usually invoke the delegate method `textView(_:shouldChangeTextIn:replacementText:)`.

This does not appear to be true if the user taps a suggestion on the predictive keyboard. In that case, the delegate method is called twice.

Invocation 1:
    Invoked in response to the change in the text view. This is expected and is the same behaviour as typing on the keyboard.

Invocation 2:
    Invoked as part of the `text` setter. This is unwanted behaviour as we intercept replacement text via `textView(_:shouldChangeTextIn:replacementText:)`and set the text property manually. This is currently causing predictive words to appear twice.

The docs state "The text view calls this method whenever the user types a new character or deletes an existing character." which leads me to believe the second invocation is unexpected behaviour.

Steps to Reproduce:
1. Intercept replacement text in `textView(_:shouldChangeTextIn:replacementText:)` and set the text view's `text` property manually before returning `false`.

2. Tap a word on the predictive toolbar.

Expected Results:
`textView(_:shouldChangeTextIn:replacementText:)` invoked once in response to the tap on the predictive toolbar.

Actual Results:
`textView(_:shouldChangeTextIn:replacementText:)` invoked a second time, on setting the `text` property.