SubscriberUpdateBuffer
Related Doc:
package server
Rebase the given update from its globalVersion through the target globalVersion.
Rebase the given update from its globalVersion through the target globalVersion.
At each buffered global version, the given update will be rebased onto that global version, and the global version will also be rebased on to the given update. Then, the stored global version will be replaced with the "leftovers" of that rebase. This is because any future update received from the this client is already on top of the given update, even if its globalVersion hasn't been updated. Note that this logic only affects edits to cell content where the same cell was edited by both the client update and a subsequent global version (of which the client was unaware).
This is the same logic as the client's EditBuffer (see edit_buffer.ts in polynote-frontend), except that the
rebasing logic for equal updates are opposite: on the server side, equal updates cancel each other out, while on
the client side, equal updates are preserved. Equal updates can't be preserved on the server, because that would
result in duplicate edits affecting the final state – but equal edits must be preserved on the client, because the
client's edit has already affected the client's state. This has been experimentally verified to be the only
behavior under which concurrent editing reliably operates (see KernelPublisherIntegrationTest in which simulates
"keyboard-mashing" clients using the client-side logic replicated in the polynote-frontend's EditBuffer)
The server-side logic also has additional filtering to ensure that it's not rebasing through the client's own edits, and it has some optional debug logging (TODO: remove the debug logging)
the rebased edit