Merge #12634: [refactor] Make TransactionWithinChainLimit more flexible

f77e1d34fd5f17304ce319b5f962b8005592501a test: Add MempoolAncestryTests (Karl-Johan Alm)
a08d76bcfee6f563a268933357931abe32060668 mempool: Calculate descendant maximum thoroughly (Karl-Johan Alm)
6d3568371eb2559d65a3e2334252d36a262319e8 wallet: Switch to using ancestor/descendant limits (Karl-Johan Alm)
6888195b062c8c58dd776fd10b44b25554eb1f15 wallet: Strictly greater than for ancestor caps (Karl-Johan Alm)
322b12ac4e0a8c892e81a760ff7225619248b74f Remove deprecated TransactionWithinChainLimit (Karl-Johan Alm)
47847515473b054929af0c8de3d54b6672500cab Switch to GetTransactionAncestry() in OutputEligibleForSpending (Karl-Johan Alm)
475a385a80198a46a6d99846f99b968f04e9b470 Add GetTransactionAncestry to CTxMemPool for general purpose chain limit checking (Karl-Johan Alm)
46847d69d2c1cc908fd779daac7884e365955dbd mempool: Fix max descendants check (Karl-Johan Alm)
b9ef21dd727dde33f5bd3c33226b05d07eb12aac mempool: Add explicit max_descendants (Karl-Johan Alm)

Pull request description:

  Currently, `TransactionWithinChainLimit` is restricted to single-output use, and needs to be called every time for different limits. If it is replaced with a chain limit value calculator, that can be called once and reused, and is generally more flexible (see e.g. #12257).

  Update: this PR now corrects usage of max ancestors / max descendants, including calculating the correct max descendant value, as advertised for the two limits.

  ~~This change also makes `nMaxAncestors` signed, as the replacement method will return `-1` for "not in the mempool", which is different from "0", which means "no ancestors/descendants in mempool".~~

  ~~This is a subset of #12257.~~

Tree-SHA512: aa59c849360542362b3126c0e29d44d3d58f11898e277d38c034dc4b86a5b4500f77ac61767599ce878c876b5c446fec9c02699797eb2fa41e530ec863a00cf9

1 files changed, 6 insertions, 2 deletions

diff --git a/src/txmempool.h b/src/txmempool.h
index ca7b1cd4be..bda812b42f 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -498,6 +498,7 @@ public:
 
     const setEntries & GetMemPoolParents(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
     const setEntries & GetMemPoolChildren(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
+    uint64_t CalculateDescendantMaximum(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
 private:
     typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap;
 
@@ -619,8 +620,11 @@ public:
     /** Expire all transaction (and their dependencies) in the mempool older than time. Return the number of removed transactions. */
     int Expire(int64_t time);
 
-    /** Returns false if the transaction is in the mempool and not within the chain limit specified. */
-    bool TransactionWithinChainLimit(const uint256& txid, size_t chainLimit) const;
+    /**
+     * Calculate the ancestor and descendant count for the given transaction.
+     * The counts include the transaction itself.
+     */
+    void GetTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants) const;
 
     unsigned long size()
     {