React-spring: useTransition causes rerender loop when array has fewer items

[BertCh]

🐛 Bug Report

Each re-render useTransition is passed an array from state. This works fine when adding objects, but when objects are removed from the array it triggers a rerender loop.
possibly related: #636

To Reproduce

Steps to reproduce the behavior:
press the buttons in the sandbox

Expected behavior

The animation seems to get run properly, but the rerender loop is unexpected.

Link to repro (highly encouraged)

bug with useState hook: https://codesandbox.io/s/usetransition-bug-state-v49uq

bug with useReducer hook (slightly more complex): https://codesandbox.io/s/usetransition-bug-25xbr

Environment

• react-spring v8.x.x or 9.x beta
• react v16.8

[aleclarson]

Please try with the latest canary.

Note: You'll need to update your useTransition calls. See #809.

[BertCh]

woo it works!
Thanks for responding so quickly & for maintaining a good library 👍

[arackaf]

The new useTransition api looks amazing - really looking forward to react-spring 9.

I found this issue after some maddening debugging, trying to figure out why my expired items were not unmounted. Do you think a quick note in your docs warning of this might be useful? EDIT - argghhh I just realized my problem was 100% a consequence of running in concurrent mode. Play on the bleeding edge, get cut :). /EDIT

Also, no pressure of course, but can I ask when you hope to have the current canary released? Very eager to get my hands on it. Thanks for all the hard work - truly appreciated