policy: don't CheckEphemeralSpends on reorg by instagibbs · Pull Request #33616 · bitcoin/bitcoin

instagibbs · 2025-10-13T17:37:23Z

Similar reasoning to #33504

During a deeper reorg it's possible that a long sequence of dust-having transactions that are connected in a linear fashion. On reorg, this could cause each subsequent "generation" to be rejected. These rejected transactions may contain a large amount of competitive fees via normal means.

PreCheck based PreCheckEphemeralSpends is left in place because we wouldn't have relayed them prior to the reorg.

DrahtBot · 2025-10-13T17:37:27Z

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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33616.

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ACK	darosior, ismaelsadeeq, sedited

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Conflicts

Reviewers, this pull request conflicts with the following ones:

#33959 (test: use ForkGenerator to deduplicate reorg test code by yuvicc)

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Possible typos and grammar issues:

Does context-less checks about a single transaction. -> Performs context-less checks on a single transaction. [Subject-verb mismatch: "Does ... checks" is ungrammatical; "Performs ... checks on" is correct and clearer]

^{2026-02-25 14:24:30}

test/functional/test_framework/blocktools.py

glozow

This seems to make sense. I'd feel more confident if we add some more test cases for topologies and reorg scenarios that this does (not) apply to?

glozow · 2025-10-15T17:33:00Z

src/validation.cpp

@@ -1608,7 +1608,7 @@ PackageMempoolAcceptResult MemPoolAccept::AcceptMultipleTransactions(const std::
    }

    // Now that we've bounded the resulting possible ancestry count, check package for dust spends
-    if (m_pool.m_opts.require_standard) {
+    if (!args.m_bypass_limits && m_pool.m_opts.require_standard) {


I think it's impossible for m_bypass_limits to be true in this function, so undoing this diff doesn't make a difference. Could we omit it or Assume(!args.m_bypass_limits)?

Took feedback in other PR ahead of time #33504 (comment)

I can definitely put an Assume() on it.

Mild preference for consistency between the two checks that are disabled upon reorgs: either we gate both TRUC and ephemeral dust on !bypass_limits in both code paths, or we gate both only on the AcceptSingleTx code path. Since the TRUC bypass is not enabled in AccecptMultiTx, the easier seems to be dropping it in this PR. Assume sounds good.

Not a blocker for me. Happy to re-ACK if you drop it and/or add an Assume.

This confused me until I read the discussion here. I would appreciate if it were dropped.

instagibbs · 2025-11-25T16:04:58Z

marking as draft for now until it becomes dependency-less and I've looked over the tests some more

instagibbs · 2025-12-01T17:42:41Z

Added some more coverage and now has no dependencies.

ismaelsadeeq · 2026-02-20T14:01:19Z

Concept ACK

darosior · 2026-02-20T19:59:12Z

Concept ACK

ismaelsadeeq · 2026-02-24T13:00:44Z

ACK a5299c3

The comment for CheckEphemeralSpends seems incorrect. It currently states, "Must be called for each package/transaction with dust." That is no longer the case. It wasn’t the case before either, because on the test chain, you can override and accept non-standard transactions, and then it won’t be called.

instagibbs · 2026-02-24T15:42:50Z

@ismaelsadeeq dropped the "must" in both places, since they are not true.

ismaelsadeeq · 2026-02-24T16:13:04Z

reACK 2854de7

9a3631b1b..2854de7b fixed a comment as mentioned in #33616 (comment)

darosior

ACK 2854de7

sedited · 2026-02-25T13:31:46Z

Approach ACK

Looks good, but I would prefer to see glozow's original comment addressed.

darosior · 2026-02-25T14:27:56Z

re-ACK 33fbaed

ismaelsadeeq · 2026-02-25T15:07:49Z

reACK 33fbaed

sedited

ACK 33fbaed

instagibbs changed the title ~~2025 10 bypass checkephemeral~~ policy: don't CheckEphemeralSpends on reorg Oct 13, 2025

DrahtBot added the TX fees and policy label Oct 13, 2025

DrahtBot mentioned this pull request Oct 13, 2025

Cluster mempool followups #33591

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optout21 reviewed Oct 14, 2025

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test/functional/test_framework/blocktools.py Outdated Show resolved Hide resolved

DrahtBot mentioned this pull request Oct 14, 2025

Cluster mempool implementation #28676

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instagibbs mentioned this pull request Oct 14, 2025

test: Fix reorg patterns in tests to use proper fork-based approach #32587

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DrahtBot mentioned this pull request Oct 15, 2025

Cluster mempool #33629

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glozow reviewed Oct 15, 2025

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DrahtBot mentioned this pull request Nov 18, 2025

policy: allow <minrelay txns in package context if paid for by cpfp #33892

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DrahtBot added the Needs rebase label Nov 25, 2025

DrahtBot mentioned this pull request Nov 25, 2025

Replace cluster linearization algorithm with SFL #32545

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instagibbs force-pushed the 2025-10-bypass_checkephemeral branch from 04832d0 to 0ae5db4 Compare November 25, 2025 16:01

instagibbs marked this pull request as draft November 25, 2025 16:01

DrahtBot removed the Needs rebase label Nov 25, 2025

instagibbs force-pushed the 2025-10-bypass_checkephemeral branch from 0ae5db4 to 9ddde71 Compare November 26, 2025 14:09

DrahtBot mentioned this pull request Nov 30, 2025

test: use ForkGenerator to deduplicate reorg test code #33959

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instagibbs force-pushed the 2025-10-bypass_checkephemeral branch from 9ddde71 to a5299c3 Compare December 1, 2025 17:36

instagibbs marked this pull request as ready for review December 1, 2025 17:37

fanquake added this to the 31.0 milestone Dec 4, 2025

DrahtBot requested a review from darosior February 24, 2026 13:00

instagibbs force-pushed the 2025-10-bypass_checkephemeral branch from a5299c3 to 2854de7 Compare February 24, 2026 15:42

darosior approved these changes Feb 24, 2026

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policy: don't CheckEphemeralSpends on reorg

33fbaed

instagibbs force-pushed the 2025-10-bypass_checkephemeral branch from 2854de7 to 33fbaed Compare February 25, 2026 14:23

DrahtBot requested review from ismaelsadeeq and sedited February 25, 2026 14:28

sedited approved these changes Feb 25, 2026

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sedited merged commit 7c80301 into bitcoin:master Feb 25, 2026
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bolty-from-atl-bitlab bot mentioned this pull request Mar 7, 2026

Bitcoin Socratic Seminar #49 - Topic Suggestions atlantabitdevs/atlbit.dev#136

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