Fix vnode DOM not existing

[LuKks]

I'm getting this error:

Uncaught (in promise) TypeError: Cannot read properties of null (reading '__P')
    at index.js+app+app:57:20
    at Array.forEach (<anonymous>)
    at Object.replaceComponent (index.js+app+app:56:10)

I couldn't trace on how to minimally reproduce the error but it happens consistently

It could be an edge case bug or maybe it's my naive way of implementing live reload, it's more or less like so:

const reload = useImporter(file.href)

const original = await import(reload.url + FILE_POSTFIX)
const previous = await reload.import(false)
let uncached

try {
  uncached = await reload.import(true)
} catch (error) {
  await handleEdgeCases(error)
}

const modules = Object.keys(original)
  .concat(Object.keys(previous))
  .filter(uniques)

for (const name of modules) {
  if (!uncached[name]) continue

  window.__PREFRESH__.replaceComponent(original[name], uncached[name], true)
  window.__PREFRESH__.replaceComponent(previous[name], uncached[name], true)
}

I'm always resetting the state there, and I didn't implement the signature comparison because it's too complex, but this has been working perfectly

[changeset-bot]

🦋 Changeset detected

Latest commit: b621c1b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@prefresh/core	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[JoviDeCroock]

The main reason why something like this could happen is becauase you are invoking replaceComponent on a VNode which has exited the DOM. This is something you are doing as you are invoking replaceComponent twice in the above. Removing the invocation where you remove previous and just doing replace(new, old) it should work correctly.

EDIT: the tests fail as well for non-resetting behavior

[LuKks]

Tried to remove the second replace but it's the first one that fails replaceComponent(original[name], uncached[name], true). I also tried the reverse, and other combinations

The first time ever that the code gets executed fails so in this case there is no double replace or anything like that

This issue only happens on a specific file, so in all other files it's fine. To defend the double replaceComponent, if I remember correctly it's required in case someone changes the exports

Btw you said replace(new, old) but I'm using it like replace(old, new) which I think it's the correct API. Your way doesn't throw but it doesn't update the component

[LuKks]

I think the PR is still valid because it should not throw if possible, this literally fixes the issue and it allows the component to update correctly. It just that it would be cool to know exactly what is happening haha

Thanks for the help!

[LuKks]

CI error seems unrelated because same one happened on main branch recently. Maybe if we re-run the CI several times

[JoviDeCroock]

Superseded by #514 apologies for the flaky tests, created an issue for that