Merge bitcoin/bitcoin#28251: validation: fix coins disappearing mid-package evaluation

32c1dd1ad65af0ad4d36a56d2ca32a8481237e68 [test] mempool coins disappearing mid-package evaluation (glozow)
a67f460c3fd1c7eb8070623666d887eefccff0d6 [refactor] split setup in mempool_limit test (glozow)
d08696120e3647b4c2cd0ae8d6e57dea12418b7c [test framework] add ability to spend only confirmed utxos (glozow)
3ea71feb11c261f002ed918f91f3434fd8a23589 [validation] don't LimitMempoolSize in any subpackage submissions (glozow)
d227b7234cd4cfd7c593ffcf8e2f24573d1ebea5 [validation] return correct result when already-in-mempool tx gets evicted (glozow)
9698b81828ff98820fa49c83ca364063233374c6 [refactor] back-fill results in AcceptPackage (glozow)
8ad7ad33929ee846a55a43c55732be0cb8973060 [validation] make PackageMempoolAcceptResult members mutable (glozow)
03b87c11ca0705e1d6147b90da33ce555f9f41c8 [validation] add AcceptSubPackage to delegate Accept* calls and clean up m_view (glozow)
3f01a3dab1c4ee37fd4093b6a0a3b622f53e231d [CCoinsViewMemPool] track non-base coins and allow Reset (glozow)
7d7f7a1189432b1b6245ba25df572229870567cb [policy] check for duplicate txids in package (glozow)

Pull request description:

  While we are evaluating a package, we split it into "subpackages" for evaluation (currently subpackages all have size 1 except the last one). If a subpackage has size 1, we may add a tx to mempool and call `LimitMempoolSize()`, which evicts transactions if the mempool gets full. We handle the case where the just-submitted transaction is evicted immediately, but we don't handle the case in which a transaction from a previous subpackage (either just submitted or already in mempool) is evicted. Mainly, since the coins created by the evicted transaction are cached in `m_view`, we don't realize the UTXO has disappeared until `CheckInputsFromMempoolAndCache` asserts that they exist. Also, the returned `PackageMempoolAcceptResult` reports that the transaction is in mempool even though it isn't anymore.

  Fix this by not calling `LimitMempoolSize()` until the very end, and editing the results map with "mempool full" if things fall out.

  Pointed out by instagibbs in https://github.com/bitcoin/bitcoin/commit/faeed687e5cde5e32750d93818dd1d4add837f24 on top of the v3 PR.

ACKs for top commit:
  instagibbs:
    reACK https://github.com/bitcoin/bitcoin/pull/28251/commits/32c1dd1ad65af0ad4d36a56d2ca32a8481237e68

Tree-SHA512: 61e7f69db4712e5e5bfa27d037ab66bdd97f1bf60a8d9ffb96adb1f0609af012c810d681102ee5c7baec7b5fe8cb7c304a60c63ccc445d00d86a2b7f0e7ddb90

1 files changed, 7 insertions, 0 deletions

diff --git a/src/policy/packages.cpp b/src/policy/packages.cpp
index 6e70a94088..a901ef8f38 100644
--- a/src/policy/packages.cpp
+++ b/src/policy/packages.cpp
@@ -37,6 +37,13 @@ bool CheckPackage(const Package& txns, PackageValidationState& state)
     std::unordered_set<uint256, SaltedTxidHasher> later_txids;
     std::transform(txns.cbegin(), txns.cend(), std::inserter(later_txids, later_txids.end()),
                    [](const auto& tx) { return tx->GetHash(); });
+
+    // Package must not contain any duplicate transactions, which is checked by txid. This also
+    // includes transactions with duplicate wtxids and same-txid-different-witness transactions.
+    if (later_txids.size() != txns.size()) {
+        return state.Invalid(PackageValidationResult::PCKG_POLICY, "package-contains-duplicates");
+    }
+
     for (const auto& tx : txns) {
         for (const auto& input : tx->vin) {
             if (later_txids.find(input.prevout.hash) != later_txids.end()) {