if riot is slow, pasting into the RTE can race with typing

[ara4n]

I think this is the root of most of my RTE problems - if riot is being laggy, then pressing cmd-V to paste a URL may race with the stuff I am trying to type after it, causing the typing to appear before the thing I paste, despite me having pasted first.

[lukebarnard1]

I've seen a bug similar to this one where the selection state gets needlessly set to the beginning of the composer and I'm not convinced it's a race. (See #4675)

[lukebarnard1]

Upon investigation, this looks like a race in draft-js between paste handling and character insertion. This is likely because sometimes draft does native character insertions, which are done on (potentially) a different event-loop to the pasting.

So when perf drops, the native character insertions get done first, followed by the pastes.

(N.B. useful snippet to introduce deliberate lag :3 setInterval(() => {i = 0; while ( i++ < 10000 ) console.debug(i);}, 2000); and as a test one can repeatedly alternate between pasting something like "paste" and inserting a "0". The bug is observed when you see "pastepaste")

Bug filled upstream: facebookarchive/draft-js#1325

[ara4n]

fixed in matrix-org/matrix-react-sdk#1890, thank goodness