Fix: Switch to real dom before rebuilding fullsnapshot

[YunFeng0817]

This pull request makes rrdom optimization robust.

1. Normally rebuilding full snapshots should not be under a virtual dom environment.
   But if the order of data events has some issues, it might be possible.
   Adding a check to avoid any potential issues.

2. Fix the bug: If an RRNode appends the same child twice, the child nodes will become an infinite linked list. This is a bug imported in improve rrdom performance #1127

[changeset-bot]

🦋 Changeset detected

Latest commit: d63cc1e

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

This PR includes changesets to release 7 packages

Name	Type
rrweb	Patch
rrdom	Patch
rrweb-snapshot	Patch
rrdom-nodejs	Patch
rrweb-player	Patch
@rrweb/types	Patch
@rrweb/web-extension	Patch

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[Juice10]

By setting usingVirtualDom to false, aren’t you essentially turning off all rrdom/virtual dom optimizations whenever you hit a full snapshot?

[YunFeng0817]

By setting usingVirtualDom to false, aren’t you essentially turning off all rrdom/virtual dom optimizations whenever you hit a full snapshot?

Yes, because if a new fullsnapshot is rebuilt, the status of the existing virtual dom doesn't mean anything as it represents the previous snapshot. usingVirtualDom is an internal switch that determines the current dom environment. It's different from the replayer's configuration useVirtualDom.

Virtual dom optimization shall only be activated if there are incremental node mutations. Refer to the code: https://github.com/rrweb-io/rrweb/blob/master/packages/rrweb/src/replay/index.ts#L1340-L1343

This pull request won't change any logic for correct event data. It is made for data with flaws. Previous parentFragment optimization can tolerate those flaws. So I think the new version should also have the capability.

[eoghanmurray]

For future work: I feel like the usingVirtualDom global is dangerous; I'd prefer that this variable be passed down the call chain to each function rather than relying on global state. I've come across a situation in last few weeks where after an error, more errors were generated because it's state wasn't reset.

[YunFeng0817]

Your suggestion can also help. I think if this pull request is merged, there are not many serious bugs left.