Preact: Strictly equal VNodes should short-circuit diffing

[localvoid]

Libraries like react-redux are relying on this behavior for optimizations.

Preact X: https://codesandbox.io/s/4q307zk7o9
React: https://codesandbox.io/s/m3o2qy7398

[asilvas]

Surprised v10 is being rolled out without resolving this first as some apps will experience massive slowdowns by upgrading.

[JoviDeCroock]

No apps should be faster by upgrading normally, are you experiencing something else @asilvas

[marvinhagemeister]

Yup we didn't have that optimization in 8.x either iirc.

[asilvas]

I see, wasn't aware this was a pre-existing issue. In my testing it resulted in significant slowness compared to React, and must have assumed it was related to v10.

[marvinhagemeister]

This was added earlier this year with #2386 :tada: Updating the codesandbox to the latest version of Preact resolves it :+1: