Merge bitcoin/bitcoin#28948: v3 transaction policy for anti-pinning

29029df5c700e6940c712028303761d91ae15847 [doc] v3 signaling in mempool-replacements.md (glozow)
e643ea795e4b6fea4a6bbb3d72870ee6a4c836b1 [fuzz] v3 transactions and sigop-adjusted vsize (glozow)
1fd16b5c62f54c7f4c60122acd65d852f63d1e8b [functional test] v3 transaction submission (glozow)
27c8786ba918a42c860e6a50eaee9fdf56d7c646 test framework: Add and use option for tx-version in MiniWallet methods (MarcoFalke)
9a1fea55b29fe025355b06b45e3d77d192acc635 [policy/validation] allow v3 transactions with certain restrictions (glozow)
eb8d5a2e7d939dd3ee683486e98702079e0dfcc0 [policy] add v3 policy rules (glozow)
9a29d470fbb62bbb27d517efeafe46ff03c25f54 [rpc] return full string for package_msg and package-error (glozow)
158623b8e0726dff7eae4288138f1710e727db9c [refactor] change Workspace::m_conflicts and adjacent funcs/structs to use Txid (glozow)

Pull request description:

  See #27463 for overall package relay tracking.

  Delving Bitcoin discussion thread: https://delvingbitcoin.org/t/v3-transaction-policy-for-anti-pinning/340
  Delving Bitcoin discussion for LN usage: https://delvingbitcoin.org/t/lightning-transactions-with-v3-and-ephemeral-anchors/418

  Rationale:
  - There are various pinning problems with RBF and our general ancestor/descendant limits. These policies help mitigate many pinning attacks and make package RBF feasible (see #28984 which implements package RBF on top of this). I would focus the most here on Rule 3 pinning. [1][2]
  - Switching to a cluster-based mempool (see #27677 and #28676) requires the removal of CPFP carve out, which applications depend on. V3 + package RBF + ephemeral anchors + 1-parent-1-child package relay provides an intermediate solution.

  V3 policy is for "Priority Transactions." [3][4] It allows users to opt in to more restrictive topological limits for shared transactions, in exchange for the more robust fee-bumping abilities that offers. Even though we don't have cluster limits, we are able to treat these transactions as having as having a maximum cluster size of 2.

  Immediate benefits:

  - You can presign a transaction with 0 fees (not just 1sat/vB!) and add a fee-bump later.
  - Rule 3 pinning is reduced by a significant amount, since the attacker can only attach a maximum of 1000vB to your shared transaction.

  This also enables some other cool things (again see #27463 for overall roadmap):
  - Ephemeral Anchors
  - Package RBF for these 1-parent-1-child packages. That means e.g. a commitment tx + child can replace another commitment tx using the child's fees.
  - We can transition to a "single anchor" universe without worrying about package limit pinning. So current users of CPFP carve out would have something else to use.
  - We can switch to a cluster-based mempool [5] (#27677 #28676), which removes CPFP carve out [6].

  [1]: Original mailing list post and discussion about RBF pinning problems https://gist.github.com/glozow/25d9662c52453bd08b4b4b1d3783b9ff, https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-January/019817.html
  [2]: A FAQ is "we need this for cluster mempool, but is this still necessary afterwards?" There are some pinning issues that are fixed here and not fully fixed in cluster mempool, so we will still want this or something similar afterward.
  [3]: Mailing list post for v3 https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-September/020937.html
  [4]: Original PR #25038 also contains a lot of the discussion
  [5]: https://delvingbitcoin.org/t/an-overview-of-the-cluster-mempool-proposal/393/7
  [6]: https://delvingbitcoin.org/t/an-overview-of-the-cluster-mempool-proposal/393#the-cpfp-carveout-rule-can-no-longer-be-supported-12

ACKs for top commit:
  sdaftuar:
    ACK 29029df5c700e6940c712028303761d91ae15847
  achow101:
    ACK 29029df5c700e6940c712028303761d91ae15847
  instagibbs:
    ACK 29029df5c700e6940c712028303761d91ae15847 modulo that

Tree-SHA512: 9664b078890cfdca2a146439f8835c9d9ab483f43b30af8c7cd6962f09aa557fb1ce7689d5e130a2ec142235dbc8f21213881baa75241c5881660f9008d68450

1 files changed, 1 insertions, 1 deletions

diff --git a/src/policy/rbf.h b/src/policy/rbf.h
index fff9828482..5a33ed64a3 100644
--- a/src/policy/rbf.h
+++ b/src/policy/rbf.h
@@ -80,7 +80,7 @@ std::optional<std::string> HasNoNewUnconfirmed(const CTransaction& tx, const CTx
  * @returns error message if the sets intersect, std::nullopt if they are disjoint.
  */
 std::optional<std::string> EntriesAndTxidsDisjoint(const CTxMemPool::setEntries& ancestors,
-                                                   const std::set<uint256>& direct_conflicts,
+                                                   const std::set<Txid>& direct_conflicts,
                                                    const uint256& txid);
 
 /** Check that the feerate of the replacement transaction(s) is higher than the feerate of each