http: Make HTTPRequest::m_client a weak_ptr #36007

1. 
   hodlinator commented at 8:03 AM on August 18, 2026: contributor

   Removes the need for HTTPClient::ReleaseRequest() as the client<->request cycle is broken. Not having to remember to call ReleaseRequest() reduces cognitive load.

   Follow-up to #35735.

2. http: Make HTTPRequest::m_client a weak_ptr

   This removes the need for HTTPClient::ReleaseRequest() as the client<->request cycle is broken. Not having to remember to call ReleaseRequest() reduces cognitive load.

   979a42ec17
3. DrahtBot added the label RPC/REST/ZMQ on Aug 18, 2026
4. 
   DrahtBot commented at 8:03 AM on August 18, 2026: contributor

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   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/36007.

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   Possible typos and grammar issues:

   • // This must happen between, leaving m_send_ready set on an empty buffer. -> sentence is incomplete; missing words make the intended meaning unclear.

   ^{2026-08-18 08:03:53}

5. fanquake requested review from pinheadmz on Aug 18, 2026
6. fanquake requested review from fjahr on Aug 18, 2026
7. DrahtBot added the label CI failed on Aug 18, 2026
8. 
   fanquake commented at 9:36 AM on August 18, 2026: member

   Restarted the CI. I think the failure was #34367.

9. 
   pinheadmz commented at 9:59 AM on August 18, 2026: member

   Will a weak pointer still keep the client connection open if a request is being handled in a worker thread, but the IO loop has dropped I from m_connected ?

10. DrahtBot removed the label CI failed on Aug 18, 2026
11. 
    hodlinator commented at 11:36 AM on August 18, 2026: contributor

    Will a weak pointer still keep the client connection open if a request is being handled in a worker thread, but the IO loop has dropped it from m_connected ?

    HTTPRequest::WriteReply() could be holding an ephemeral shared_ptr created by locking the weak_ptr. This would prevent the HTTPRemoteClient from being destroyed directly within HTTPServer::DisconnectClients() running on another thread. Destruction would in that case happen as HTTPRequest::WriteReply() exits, on that thread.

    StopHTTPServer() blocks until the ThreadPool::Stop() has shut down all workers before calling InterruptNet()/JoinSocketsThreads()/ClearConnectedClients().

12. pinheadmz approved
13. 
    pinheadmz commented at 11:42 AM on August 18, 2026: member

    untested ACK 979a42ec17369b55a3a20c9e45965e6733fbeb19

    Thanks for the improvement and the explanation 🏆

14. fanquake merged this on Aug 18, 2026
15. fanquake closed this on Aug 18, 2026

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16. 
    winterrdog commented at 12:59 PM on August 18, 2026: contributor

    post-merge ACK 979a42ec17369b55a3a20c9e45965e6733fbeb19

17. 
    fjahr commented at 2:53 PM on August 18, 2026: contributor

    Code change looks good to me, utACK 979a42ec17369b55a3a20c9e45965e6733fbeb19.

    But a bit of documentation is no longer correct after this change. For example inhttpserver.h the DisconnectClients() doc comment still says:

    * Close underlying socket connections for flagged clients
    * by removing their shared pointer from m_connected. If an HTTPRemoteClient
    * is busy in a worker thread, its connection will be closed once that
    * job is done and the HTTPRequest is out of scope.
    

    Now the connection is now closed before the job is done unless I am confused.

    There are also mention of the shared pointers being present in worker threads which does not seem relevant anymore: https://github.com/bitcoin/bitcoin/blob/15a7a4ed7c4d0952ce966087e55a9a3e2f28ec1d/src/httpserver.h#L334 and https://github.com/bitcoin/bitcoin/blob/15a7a4ed7c4d0952ce966087e55a9a3e2f28ec1d/src/httpserver.cpp#L1087.

18. hodlinator deleted the branch on Aug 18, 2026
19. 
    hodlinator commented at 9:30 AM on August 19, 2026: contributor

    Thanks for catching the out of date comments @fjahr! Please continue that discussion in follow-up #36020.

Review Requested
fjahr