Merge bitcoin/bitcoin#33591: Cluster mempool followups

b8d279a81c doc: add comment to explain correctness of GatherClusters() (Suhas Daftuar)
aba7500a30 Fix parameter name in getmempoolcluster rpc (Suhas Daftuar)
6c1325a091 Rename weight -> clusterweight in RPC output, and add doc explaining mempool terminology (Suhas Daftuar)
bc2eb931da Require mempool lock to be held when invoking TRUC checks (Suhas Daftuar)
957ae23241 Improve comments for getTransactionAncestry to reference cluster counts instead of descendants (Suhas Daftuar)
d97d6199ce Fix comment to reference cluster limits, not chain limits (Suhas Daftuar)
a1b341ef98 Sanity check feerate diagram in CTxMemPool::check() (Suhas Daftuar)
23d6f457c4 rpc: improve getmempoolcluster output (Suhas Daftuar)
d2dcd37aac Avoid using mapTx.modify() to update modified fees (Suhas Daftuar)
d84ffc24d2 doc: add release notes snippet for cluster mempool (Suhas Daftuar)
b0417ba944 doc: Add design notes for cluster mempool and explain new mempool limits (Suhas Daftuar)
2d88966e43 miner: replace "package" with "chunk" (Suhas Daftuar)
6f3e8eb300 Add a GetFeePerVSize() accessor to CFeeRate, and use it in the BlockAssembler (Suhas Daftuar)
b5f245f6f2 Remove unused DEFAULT_ANCESTOR_SIZE_LIMIT_KVB and DEFAULT_DESCENDANT_SIZE_LIMIT_KVB (Suhas Daftuar)
1dac54d506 Use cluster size limit instead of ancestor size limit in txpackage unit test (Suhas Daftuar)
04f65488ca Use cluster size limit instead of ancestor/descendant size limits when sanity checking TRUC policy limits (Suhas Daftuar)
634291a7dc Use cluster limits instead of ancestor/descendant limits when sanity checking package policy limits (Suhas Daftuar)
fc18ef1f3f Remove ancestor and descendant vsize limits from MemPoolLimits (Suhas Daftuar)
ed8e819121 Warn user if using -limitancestorsize/-limitdescendantsize that the options have no effect (Suhas Daftuar)
80d8df2d47 Invoke removeUnchecked() directly in removeForBlock() (Suhas Daftuar)
9292570f4c Rewrite GetChildren without sets (Suhas Daftuar)
3e39ea8c30 Rewrite removeForReorg to avoid using sets (Suhas Daftuar)
a3c31dfd71 scripted-diff: rename AddToMempool -> TryAddToMempool (Suhas Daftuar)
a5a7905d83 Simplify removeRecursive (Suhas Daftuar)
01d8520038 Remove unused argument to RemoveStaged (Suhas Daftuar)
bc64013e6f Remove unused variable (cacheMap) in mempool (Suhas Daftuar)

Pull request description:

  As suggested in the main cluster mempool PR (https://github.com/bitcoin/bitcoin/pull/28676#pullrequestreview-3177119367), I've pulled out some of the non-essential optimizations and cleanups into this separate PR.

  Will continue to add more commits here to address non-blocking suggestions/improvements as they come up.

ACKs for top commit:
  instagibbs:
    ACK https://github.com/bitcoin/bitcoin/pull/33591/commits/b8d279a81c16fe9f5b6d422e518c77344e217d4f
  sipa:
    ACK b8d279a81c

Tree-SHA512: 1a05e99eaf8db2e274a1801307fed5d82f8f917e75ccb9ab0e1b0eb2f9672b13c79d691d78ea7cd96900d0e7d5031a3dd582ebcccc9b1d66eb7455b1d3642235

test/functional/mempool_reorg.py

@@ -164,7 +164,7 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         assert_raises_rpc_error(-26, "non-final", self.nodes[0].sendrawtransaction, timelock_tx)
 
         self.log.info("Broadcast and mine spend_2 and spend_3")
-        wallet.sendrawtransaction(from_node=self.nodes[0], tx_hex=spend_2['hex'])
+        spend_2_id = wallet.sendrawtransaction(from_node=self.nodes[0], tx_hex=spend_2['hex'])
         wallet.sendrawtransaction(from_node=self.nodes[0], tx_hex=spend_3['hex'])
         self.log.info("Generate a block")
         self.generate(self.nodes[0], 1)
@@ -172,7 +172,7 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         assert_raises_rpc_error(-26, 'non-final', self.nodes[0].sendrawtransaction, timelock_tx)
 
         self.log.info("Create spend_2_1 and spend_3_1")
-        spend_2_1 = wallet.create_self_transfer(utxo_to_spend=spend_2["new_utxo"])
+        spend_2_1 = wallet.create_self_transfer(utxo_to_spend=spend_2["new_utxo"], version=1)
         spend_3_1 = wallet.create_self_transfer(utxo_to_spend=spend_3["new_utxo"])
 
         self.log.info("Broadcast and mine spend_3_1")
@@ -211,6 +211,24 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         self.log.info("spend_3_1 has been re-orged out of the chain and is back in the mempool")
         assert_equal(set(self.nodes[0].getrawmempool()), {spend_1_id, spend_2_1_id, spend_3_1_id})
 
+        self.log.info("Reorg out enough blocks to get spend_2 back in the mempool, along with its child")
+
+        while (spend_2_id not in self.nodes[0].getrawmempool()):
+            b = self.nodes[0].getbestblockhash()
+            for node in self.nodes:
+                node.invalidateblock(b)
+
+        assert(spend_2_id in self.nodes[0].getrawmempool())
+        assert(spend_2_1_id in self.nodes[0].getrawmempool())
+
+        # Chain 10 more transactions off of spend_2_1
+        self.log.info("Give spend_2 some more descendants by creating a chain of 10 transactions spending from it")
+        parent_utxo = spend_2_1["new_utxo"]
+        for i in range(10):
+            tx = wallet.create_self_transfer(utxo_to_spend=parent_utxo, version=1)
+            self.nodes[0].sendrawtransaction(tx['hex'])
+            parent_utxo = tx["new_utxo"]
+
         self.log.info("Use invalidateblock to re-org back and make all those coinbase spends immature/invalid")
         b = self.nodes[0].getblockhash(first_block + 100)