[refactor] comment/naming improvements

src/rpc/rawtransaction.cpp

@@ -889,7 +889,7 @@ static RPCHelpMan testmempoolaccept()
                 "\nReturns result of mempool acceptance tests indicating if raw transaction(s) (serialized, hex-encoded) would be accepted by mempool.\n"
                 "\nIf multiple transactions are passed in, parents must come before children and package policies apply: the transactions cannot conflict with any mempool transactions or each other.\n"
                 "\nIf one transaction fails, other transactions may not be fully validated (the 'allowed' key will be blank).\n"
-                "\nThe maximum number of transactions allowed is 25 (MAX_PACKAGE_COUNT)\n"
+                "\nThe maximum number of transactions allowed is " + ToString(MAX_PACKAGE_COUNT) + ".\n"
                 "\nThis checks if transactions violate the consensus or policy rules.\n"
                 "\nSee sendrawtransaction call.\n",
                 {
@@ -905,7 +905,7 @@ static RPCHelpMan testmempoolaccept()
                 RPCResult{
                     RPCResult::Type::ARR, "", "The result of the mempool acceptance test for each raw transaction in the input array.\n"
                         "Returns results for each transaction in the same order they were passed in.\n"
-                        "It is possible for transactions to not be fully validated ('allowed' unset) if an earlier transaction failed.\n",
+                        "It is possible for transactions to not be fully validated ('allowed' unset) if another transaction failed.\n",
                     {
                         {RPCResult::Type::OBJ, "", "",
                         {
@@ -939,7 +939,6 @@ static RPCHelpMan testmempoolaccept()
         UniValue::VARR,
         UniValueType(), // VNUM or VSTR, checked inside AmountFromValue()
     });
-
     const UniValue raw_transactions = request.params[0].get_array();
     if (raw_transactions.size() < 1 || raw_transactions.size() > MAX_PACKAGE_COUNT) {
         throw JSONRPCError(RPC_INVALID_PARAMETER,
@@ -972,8 +971,8 @@ static RPCHelpMan testmempoolaccept()
     }();
 
     UniValue rpc_result(UniValue::VARR);
-    // We will check transaction fees we iterate through txns in order. If any transaction fee
+    // We will check transaction fees while we iterate through txns in order. If any transaction fee
-    // exceeds maxfeerate, we will keave the rest of the validation results blank, because it
+    // exceeds maxfeerate, we will leave the rest of the validation results blank, because it
     // doesn't make sense to return a validation result for a transaction if its ancestor(s) would
     // not be submitted.
     bool exit_early{false};

src/test/miner_tests.cpp

@@ -28,8 +28,8 @@ struct MinerTestingSetup : public TestingSetup {
     void TestPackageSelection(const CChainParams& chainparams, const CScript& scriptPubKey, const std::vector<CTransactionRef>& txFirst) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_node.mempool->cs);
     bool TestSequenceLocks(const CTransaction& tx, int flags) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_node.mempool->cs)
     {
-        CCoinsViewMemPool viewMempool(&m_node.chainman->ActiveChainstate().CoinsTip(), *m_node.mempool);
+        CCoinsViewMemPool view_mempool(&m_node.chainman->ActiveChainstate().CoinsTip(), *m_node.mempool);
-        return CheckSequenceLocks(m_node.chainman->ActiveChain().Tip(), viewMempool, tx, flags);
+        return CheckSequenceLocks(m_node.chainman->ActiveChain().Tip(), view_mempool, tx, flags);
     }
     BlockAssembler AssemblerForTest(const CChainParams& params);
 };

src/txmempool.cpp

@@ -515,9 +515,9 @@ void CTxMemPool::removeForReorg(CChainState& active_chainstate, int flags)
         LockPoints lp = it->GetLockPoints();
         assert(std::addressof(::ChainstateActive()) == std::addressof(active_chainstate));
         bool validLP =  TestLockPointValidity(active_chainstate.m_chain, &lp);
-        CCoinsViewMemPool viewMempool(&active_chainstate.CoinsTip(), *this);
+        CCoinsViewMemPool view_mempool(&active_chainstate.CoinsTip(), *this);
         if (!CheckFinalTx(active_chainstate.m_chain.Tip(), tx, flags)
-            || !CheckSequenceLocks(active_chainstate.m_chain.Tip(), viewMempool, tx, flags, &lp, validLP)) {
+            || !CheckSequenceLocks(active_chainstate.m_chain.Tip(), view_mempool, tx, flags, &lp, validLP)) {
             // Note if CheckSequenceLocks fails the LockPoints may still be invalid
             // So it's critical that we remove the tx and not depend on the LockPoints.
             txToRemove.insert(it);

src/txmempool.h

@@ -874,7 +874,8 @@ protected:
 public:
     CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn);
     bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
-    /** Add the coins created by this transaction. */
+    /** Add the coins created by this transaction. These coins are only temporarily stored in
+     * m_temp_added and cannot be flushed to the back end. Only used for package validation. */
     void PackageAddTransaction(const CTransactionRef& tx);
 };
 

src/validation.cpp

@@ -482,7 +482,7 @@ public:
     /**
     * Multiple transaction acceptance. Transactions may or may not be interdependent,
     * but must not conflict with each other. Parents must come before children if any
-    * dependencies exist, otherwise a TX_MISSING_INPUTS error will be returned.
+    * dependencies exist.
     */
     PackageMempoolAcceptResult AcceptMultipleTransactions(const std::vector<CTransactionRef>& txns, ATMPArgs& args) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
@@ -1148,9 +1148,9 @@ PackageMempoolAcceptResult MemPoolAccept::AcceptMultipleTransactions(const std::
             return PackageMempoolAcceptResult(package_state, std::move(results));
         }
         // Make the coins created by this transaction available for subsequent transactions in the
-        // package to spend. Since we already checked conflicts in the package and RBFs are
+        // package to spend. Since we already checked conflicts in the package and we don't allow
-        // impossible, we don't need to track the coins spent. Note that this logic will need to be
+        // replacements, we don't need to track the coins spent. Note that this logic will need to be
-        // updated if RBFs in packages are allowed in the future.
+        // updated if package replace-by-fee is allowed in the future.
         assert(args.disallow_mempool_conflicts);
         m_viewmempool.PackageAddTransaction(ws.m_ptx);
     }
@@ -1227,7 +1227,6 @@ PackageMempoolAcceptResult ProcessNewPackage(CChainState& active_chainstate, CTx
     const PackageMempoolAcceptResult result = MemPoolAccept(pool, active_chainstate).AcceptMultipleTransactions(package, args);
 
     // Uncache coins pertaining to transactions that were not submitted to the mempool.
-    // Ensure the cache is still within its size limits.
     for (const COutPoint& hashTx : coins_to_uncache) {
         active_chainstate.CoinsTip().Uncache(hashTx);
     }

src/validation.h

@@ -234,11 +234,13 @@ MempoolAcceptResult AcceptToMemoryPool(CChainState& active_chainstate, CTxMemPoo
                                        bool bypass_limits, bool test_accept=false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 /**
-* Atomically test acceptance of a package. If the package only contains one tx, package rules still apply.
+* Atomically test acceptance of a package. If the package only contains one tx, package rules still
+* apply. Package validation does not allow BIP125 replacements, so the transaction(s) cannot spend
+* the same inputs as any transaction in the mempool.
 * @param[in]    txns                Group of transactions which may be independent or contain
-*                                   parent-child dependencies. The transactions must not conflict, i.e.
+*                                   parent-child dependencies. The transactions must not conflict
-*                                   must not spend the same inputs, even if it would be a valid BIP125
+*                                   with each other, i.e., must not spend the same inputs. If any
-*                                   replace-by-fee. Parents must appear before children.
+*                                   dependencies exist, parents must appear before children.
 * @returns a PackageMempoolAcceptResult which includes a MempoolAcceptResult for each transaction.
 * If a transaction fails, validation will exit early and some results may be missing.
 */
@@ -269,9 +271,13 @@ bool TestLockPointValidity(CChain& active_chain, const LockPoints* lp) EXCLUSIVE
  * Check if transaction will be BIP68 final in the next block to be created on top of tip.
  * @param[in]   tip             Chain tip to check tx sequence locks against. For example,
  *                              the tip of the current active chain.
- * @param[in]   coins_view      Any CCoinsView that provides access to the relevant coins
+ * @param[in]   coins_view      Any CCoinsView that provides access to the relevant coins for
- *                              for checking sequence locks. Any CCoinsView can be passed in;
+ *                              checking sequence locks. For example, it can be a CCoinsViewCache
- *                              it is assumed to be consistent with the tip.
+ *                              that isn't connected to anything but contains all the relevant
+ *                              coins, or a CCoinsViewMemPool that is connected to the
+ *                              mempool and chainstate UTXO set. In the latter case, the caller is
+ *                              responsible for holding the appropriate locks to ensure that
+ *                              calls to GetCoin() return correct coins.
  * Simulates calling SequenceLocks() with data from the tip passed in.
  * Optionally stores in LockPoints the resulting height and time calculated and the hash
  * of the block needed for calculation or skips the calculation and uses the LockPoints