No more floating MSC2716 historical batches

[MadLittleMods]

No more floating MSC2716 historical batches

Part of #13970

Before

After

flowchart BT A --- annotation1>"Note: older events are at the top"] subgraph live timeline marker1>m.room.marker] ----> B -----------------> A end subgraph batch0 batch0-batch[[m.room.batch]] --> batch0-2(("2")) --> batch0-1((1)) --> batch0-0((0)) --> batch0-insertion[/m.room.insertion\] end subgraph batch1 batch1-batch[[m.room.batch]] --> batch1-2(("2")) --> batch1-1((1)) --> batch1-0((0)) --> batch1-insertion[/m.room.insertion\] end subgraph batch2 batch2-batch[[m.room.batch]] --> batch2-2(("2")) --> batch2-1((1)) --> batch2-0((0)) --> batch2-insertion[/m.room.insertion\] end batch0-insertion -.-> memberBob0(["m.room.member (bob)"]) --> memberAlice0(["m.room.member (alice)"]) batch1-insertion -.-> memberBob1(["m.room.member (bob)"]) --> memberAlice1(["m.room.member (alice)"]) batch2-insertion -.-> memberBob2(["m.room.member (bob)"]) --> memberAlice2(["m.room.member (alice)"]) marker1 -.-> batch0-insertionBase batch0-insertionBase[/m.room.insertion\] ---------------> A batch0-batch -.-> batch0-insertionBase batch1-batch -.-> batch0-insertion batch2-batch -.-> batch1-insertion %% make the annotation links invisible linkStyle 0 stroke-width:2px,fill:none,stroke:none; Loading

flowchart BT A --- annotation1>"Note: older events are at the top"] subgraph live timeline marker1>m.room.marker] ----> B -----------------> A end subgraph batch0 batch0-batch[[m.room.batch]] --> batch0-2(("2")) --> batch0-1((1)) --> batch0-0((0)) --> batch0-insertion[/m.room.insertion\] end subgraph batch1 batch1-batch[[m.room.batch]] --> batch1-2(("2")) --> batch1-1((1)) --> batch1-0((0)) --> batch1-insertion[/m.room.insertion\] end subgraph batch2 batch2-batch[[m.room.batch]] --> batch2-2(("2")) --> batch2-1((1)) --> batch2-0((0)) --> batch2-insertion[/m.room.insertion\] end batch0-insertion --> memberBob0(["m.room.member (bob)"]) --> memberAlice0(["m.room.member (alice)"]) batch1-insertion --> memberBob1(["m.room.member (bob)"]) --> memberAlice1(["m.room.member (alice)"]) batch2-insertion --> memberBob2(["m.room.member (bob)"]) --> memberAlice2(["m.room.member (alice)"]) marker1 -.-> batch0-insertionBase batch0-insertionBase[/m.room.insertion\] ---------------> A batch0-batch -.-> batch0-insertionBase batch1-batch -.-> batch0-insertion batch2-batch -.-> batch1-insertion memberAlice0 --> A memberAlice1 --> A memberAlice2 --> A %% make the annotation links invisible linkStyle 0 stroke-width:2px,fill:none,stroke:none; Loading

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Spawned from scratch changes in, #13864

Todo

• Figure out consequences around not being able to union with the current state and how power levels work if you're not the room creator
  • See MSC2716: Incrementally importing history into existing rooms matrix-spec-proposals#2716 (comment)

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file. The entry should:
  • Be a short description of your change which makes sense to users. "Fixed a bug that prevented receiving messages from other servers." instead of "Moved X method from EventStore to EventWorkerStore.".
  • Use markdown where necessary, mostly for code blocks.
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  • Start with a capital letter.
  • Feel free to credit yourself, by adding a sentence "Contributed by @github_username." or "Contributed by [Your Name]." to the end of the entry.
• Pull request includes a sign off
• Code style is correct
  (run the linters)