rpc: add optional blockhash to waitfornewblock #30635

1. 
   Sjors commented at 11:42 am on August 12, 2024: member

   The waitfornewblock is inherently racy as the tip may have changed since the last RPC call, and can even change during initial processing of this call.

   Add an optional blockhash argument so the called can specify their current tip. Return immediately if our tip is different.

   I’ve made it fail if LookupBlockIndex fails. This should never happen if the user got the block hash from our RPC in the first place.

   Builds on #30409.

2. 
   DrahtBot commented at 11:42 am on August 12, 2024: contributor

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   Conflicts

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   • #26593 (tracing: Only prepare tracepoint arguments when actually tracing by 0xB10C)

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3. DrahtBot added the label RPC/REST/ZMQ on Aug 12, 2024
4. Sjors force-pushed on Aug 12, 2024
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21. refactor: rename BlockKey to BlockRef 89a8f74bbb
22. Rename getTipHash() to getTip() and return BlockRef ebb8215f23
23. node: Track last block that received a blockTip notification

    Also signal m_tip_block_cv when StopRPC is called, for
    consistency with g_best_block_cv. This is handled in
    StopRPC instead of OnRPCStopped() because the latter
    is deleted in a later commit.
    
    Co-authored-by: TheCharlatan <seb.kung@gmail.com>
    Co-authored-by: Ryan Ofsky <ryan@ofsky.org>

    7eccdaf160
24. Add waitTipChanged to Mining interface

    Co-authored-by: TheCharlatan <seb.kung@gmail.com>

    b94b27cf05
25. rpc: add test for waitforblock and waitfornewblock 285fe9fb51
26. rpc: fix waitfornewblock description

    The waitforblock RPC method takes a hash argument and waits for that specific block.  The waitfornewblock waits for any new block. This commit fixes the documentation.

    77ec072925
27. rpc: recommend -rpcclienttimeout=0 for waitfor* de7c855b3a
28. rpc: check for negative timeout arg in waitfor* 2a40ee1121
29. Replace RPCNotifyBlockChange with waitTipChanged()

    This refactoring commit uses the newly introduced waitTipChanged mining interface method to replace the RPCNotifyBlockChange mechanism.

    dca923150e
30. Remove unused CRPCSignals

    They are no longer used for anything since RPCNotifyBlockChange was replaced with waitTipChanged() from the mining interface.

    460687a09c
31. rpc: use waitTipChanged for longpoll

    This removes the last remaining use of g_best_block by the RPC.

    e3a560ca68
32. Remove unused g_best_block 7942951e3f
33. rpc: add optional blockhash to waitfornewblock d1f1e5044c
34. Sjors force-pushed on Sep 17, 2024
35. DrahtBot removed the label Needs rebase on Sep 17, 2024
36. DrahtBot removed the label CI failed on Sep 17, 2024

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RPC/REST/ZMQ