SSR issue: hoisted vnode subtrees not getting hydrated causes HMR to fail

[tjk]

Version

3.2.11

Reproduction link

github.com

Steps to reproduce

See linked README

What is expected?

Should not error

What is actually happening?

Errors

[tjk]

If I disable the server render, the patching works fine. Otherwise, the vnodes under thead have null el.

[tjk]

So it seems like patchElement fails because vnode.el is null because hydrateElement stops recursing at table because it is hoisted (so children vnodes do not get el associated). Not sure what the problem is yet but just documenting my findings.

Since the table vnode is hoisted, the patchFlag is -1 which means children do not get hydrated. I'm guessing the table is incorrectly being hoisted?

Maybe the hoisting makes sense... but why does it not hydrate under hoisted? at the very least the elements should be hooked up even if things are static under there?

[tjk]

If someone can tell me which part of my code exploration above sounds like the problem (if any), I can attempt a patch.

Also, while I noticed a problem during HMR I imagine this could cause other problems too perhaps?