kernel: trim Chain interface #33820

1. 
   stickies-v commented at 4:50 pm on November 7, 2025: contributor

   Removes btck_chain_get_genesis and btck_chain_get_tip.

   They are trivially replaced with btck_chain_get_by_height (as indicated in the updated bitcoinkernel_wrapper.h), so I think it makes sense to trim the interface.

   For btck_chain_get_tip: on master we don’t provide any guarantees that the returned block index still corresponds to the actual tip, so the extra call doesn’t seem like a regression to me.

2. kernel: remove btck_chain_get_genesis

   It is equivalent to calling btck_chain_get_by_height(0).

   737b6566f6
3. kernel: remove btck_chain_get_tip

   It is equivalent to calling btck_chain_get_by_height with the
   height obtained from btck_chain_get_height. In neither case do we
   provide guarantees that the returned block index still corresponds
   to the actual tip.

   f4b3ba18d9
4. DrahtBot added the label Validation on Nov 7, 2025
5. 
   DrahtBot commented at 4:51 pm on November 7, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33820.

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   ACK	yuvicc
   Concept ACK	TheCharlatan

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6. 
   yuvicc commented at 2:32 pm on November 8, 2025: contributor

   ACK f4b3ba18d9bf3e7c2c55a98f3c3d98129a1fa6e2

   This makes sense to me.

7. in src/kernel/bitcoinkernel_wrapper.h:970 in f4b3ba18d9

   968@@ -969,7 +969,7 @@ class ChainView : public View<btck_Chain>
   969 
   970     BlockTreeEntry Tip() const
   

   ---

   ---

   

   TheCharlatan commented at 10:23 pm on November 8, 2025:

   I wonder if we should even keep these methods now. The previous calls to tip and genesis were at least thread safe (which these are no longer). I agree that it is not worth keeping them just for the sake of it, but also not sure if they still provide utility here.
8. 
   TheCharlatan commented at 10:24 pm on November 8, 2025: contributor

   Concept ACK

   These were introduced before we had a dedicated iterator for traversing the chain. At this point, their benefit (thread safety) is kind of marginal.

Contributors
stickies-v DrahtBot yuvicc TheCharlatan

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