BUG: CopyNodesRecursively vs Tethered nodes

[mhsdesign]

There is a bug in CopyNodesRecursively because it takes the intention to literally and copies also the classification of the start node to copy.
Initially this must have created tethered nodes just inside the tree even though they are not tethered to anything.

By removing the constraints from the main content collection, we can reproduce this using the Neos Ui: Copy the content collection and insert it as its child:

(Its not forbidden via the Neos ui to do that, in fact there are no special constraints in javascript for tethered nodes being copied: https://github.com/neos/neos-ui/blob/8271a89585c83ec0f3cf141c43e59c7f5ce1c194/packages/neos-ui-redux-store/src/CR/Nodes/selectors.ts#L420)

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It only gets interesting with these two "never" changes:

• 1.) TASK: document and assert Node.nodeName behavior #4469 in Neos9 Beta7
• 2.) TASK: Dont add useless node names on copy neos-ui#3776 in Neos9 Beta10

They made us aware of this problem because 2. was a cleanup to prevent copying the obsolete initial name (in this case main) and would insert null, which is works but not for tethered nodes. And 1. which added a sanity check to the Node's constructor that all tethered nodes better be named!

So we end up with a wrong command, which is not further validated (because we TRUST user input (what is trust?)) and emits a NodeAggregateWithNodeWasCreated event which says the nodeName is null but the state tethered

...
  "nodeName": null,
  "initialPropertyValues": [],
  "nodeAggregateClassification": "tethered",
...

That will just be projected in the database:

nodetypename	classification	name
Neos.Demo:Collection.Content.Main	tethered

Only fetching the entry is NOT possible because of the sanity check (1):

That will be thrown either when querying the node or even attempting a replay, as many catchup hooks will fetch the node from the database:

The NodeName must be set if the Node is tethered.

Currently the Neos Ui will just crash at this point when copying this and will not be reloadable:

So we are in the state of having wrong events here which need to be corrected.

As in my opinion the starting node aggregate classification should have NEVER been considered i think we need a migration that untethers these nodes:

Go through all NodeAggregateWithNodeWasCreated events, see if the class is a CopyNodesRecursively, if the classification is tethered just set it to regular as tethered is NOT allowed.

see also our slack discussions

• https://neos-project.slack.com/archives/C050C8FEK/p1726753824152529
• and https://neos-project.slack.com/archives/C04PYL8H3/p1730882312457569?thread_ts=1730799833.465089&cid=C04PYL8H3