wallet: skip APS when no partial spend exists #34362

1. 
   8144225309 commented at 4:38 am on January 21, 2026: none

   Fixes #25150

   APS (Avoid Partial Spends) runs a second coin selection pass to fully spend UTXOs sharing a scriptPubKey. This currently runs unconditionally, even when the first selection has no partial spend. Running APS unnecessarily wastes computation and can produce a worse result when there was nothing to fix.

   Detect partial spends by comparing selected vs available UTXO counts per scriptPubKey, reusing available_coins. Skip APS if none found.

   Test updated to create partial spend scenarios so tracepoints fire.

2. DrahtBot added the label Wallet on Jan 21, 2026
3. 
   DrahtBot commented at 4:38 am on January 21, 2026: 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/34362.

   Reviews

   See the guideline for information on the review process. A summary of reviews will appear here.

   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #34075 (fees: Introduce Mempool Based Fee Estimation to reduce overestimation by ismaelsadeeq)

   If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

   LLM Linter (✨ experimental)

   Possible typos and grammar issues:

   • an callback -> a callback [indefinite article incorrect before a consonant sound]
   • then then maybe -> then maybe [duplicate word]
   • “#include <d/file.capnp.proxy-types.h>“i -> “#include <d/file.capnp.proxy-types.h>” [stray “i” character after the quoted include makes the sentence malformed]
   • trying to communicating -> trying to communicate [incorrect verb form]
   • ProxySever -> ProxyServer [typo in class/name]
   • will filled with callbacks -> will be filled with callbacks [missing auxiliary verb “be”]

   2026-01-26 03:42:49

4. wallet: skip APS when no partial spend exists

   APS runs a second coin selection to fully spend UTXOs sharing a
   scriptPubKey. Currently runs unconditionally, even when the first
   selection has no partial spend and APS cannot help.
   
   Detect partial spends by comparing selected vs available UTXO counts
   per scriptPubKey inside CreateTransactionInternal, reusing available_coins.
   Add has_partial_spend to CreatedTransactionResult. Skip APS if false.
   
   Update interface_usdt_coinselection test to create partial spend scenarios
   so tracepoints fire as expected.
   
   Fixes #25150

   ce5460ced7
5. 8144225309 closed this on Jan 26, 2026

   ---

6. 8144225309 force-pushed on Jan 26, 2026
7. 
   8144225309 commented at 4:37 am on January 26, 2026: none

   This PR was corrupted by a shallow clone force-push. The corrected version is at #34405.

Contributors
8144225309 DrahtBot

Labels
Wallet