rpc: fix race condition in gettxoutsetinfo #34451

1. 
   w0xlt commented at 6:57 pm on January 29, 2026: contributor

   Fixes #34263

   A CHECK_NONFATAL assertion failure could occur in gettxoutsetinfo when a new block was connected between capturing pindex and validating it in GetUTXOStats().

   The fix removes the early pindex capture since ComputeUTXOStats() independently fetches the current best block under lock. The response now uses stats.hashBlock and stats.nHeight (the actual computed values) instead of the potentially stale pindex.

2. rpc: fix race condition in gettxoutsetinfo

   Fix an assertion failure in gettxoutsetinfo (issue #34263) caused by
   capturing the best block before releasing cs_main, then checking it
   against a potentially newer best block in GetUTXOStats().
   
   Remove the early pindex capture since ComputeUTXOStats() independently
   fetches the current best block under lock. Use stats.hashBlock and
   stats.nHeight (the actual computed values) instead of the potentially
   stale pindex when building the response.

   f3c1557288
3. DrahtBot added the label RPC/REST/ZMQ on Jan 29, 2026
4. 
   DrahtBot commented at 6:57 pm on January 29, 2026: contributor

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5. 
   fjahr commented at 9:54 pm on January 29, 2026: contributor

   Concept ACK

   Do you have a hint on how to reproduce the failure?

Contributors
w0xlt DrahtBot fjahr

Labels
RPC/REST/ZMQ