Merge bitcoin/bitcoin#22689: rpc: deprecate top-level fee fields in getmempool RPCs

2f9515f37addabde84c79926d7a24b2897a21dd1 rpc: move fees object to match help (josibake)
07ade7db8f919826c5e69bdaf7d54a6ae653175e doc: add release note for fee field deprecation (josibake)
2ee406ce3e9c252734cb391d85044ac389c34279 test: add functional test for deprecatedrpc=fees (josibake)
35d928c63237e31c99215e2d9d84782befd618d5 rpc: deprecate fee fields from mempool entries (josibake)

Pull request description:

  per #22682 , top level fee fields for mempool entries have been deprecated since 0.17 but are still returned. this PR properly deprecates them so that they are no longer returned unless `-deprecatedrpc=fees` is passed.

  the first commit takes care of deprecation and also updates `test/functional/mempool_packages.py` to only use the `fees` object. the second commit adds a new functional test for `-deprecatedrpc=fees`

  closes #22682

  ## questions for the reviewer

  * `-deprecatedrpc=fees` made the most sense to me, but happy to change if there is a name that makes more sense
  * #22682 seems to indicate that after some period of time, the fields will be removed all together. if we have a rough idea of when this will be, i can add a `TODO: fully remove in vXX` comment to `entryToJSON`

  ## testing
  to get started on testing, compile, run the tests, and start your node with the deprecated rpcs flag:

  ```bash
  ./src/bitcoind -daemon -deprecatedrpc=fees
  ```
  you should see entries with the deprecated fields like so:
  ```json
  {
    "<txid>": {
      "fees": {
        "base": 0.00000671,
        "modified": 0.00000671,
        "ancestor": 0.00000671,
        "descendant": 0.00000671
      },
      "fee": 0.00000671,
      "modifiedfee": 0.00000671,
      "descendantfees": 671,
      "ancestorfees": 671,
      "vsize": 144,
      "weight": 573,
     ...
    },
  ```
  you can also check `getmempoolentry` using any of the txid's from the output above.

  next start the node without the deprecated flag, repeat the commands from above and verify that the deprecated fields are no longer present at the top level, but present in the "fees" object

ACKs for top commit:
  jnewbery:
    reACK 2f9515f37addabde84c79926d7a24b2897a21dd1
  glozow:
    utACK 2f9515f37addabde84c79926d7a24b2897a21dd1

Tree-SHA512: b175f4d39d26d96dc5bae26717d3ccfa5842d98ab402065880bfdcf4921b14ca692a8919fe4e9969acbb5c4d6e6d07dd6462a7e0a0a7342556279b381e1a004e

1 files changed, 28 insertions, 19 deletions

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index f3abe97fc9..2011ffb4fd 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -464,23 +464,23 @@ static RPCHelpMan getdifficulty()
 static std::vector<RPCResult> MempoolEntryDescription() { return {
     RPCResult{RPCResult::Type::NUM, "vsize", "virtual transaction size as defined in BIP 141. This is different from actual serialized size for witness transactions as witness data is discounted."},
     RPCResult{RPCResult::Type::NUM, "weight", "transaction weight as defined in BIP 141."},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "fee", "transaction fee in " + CURRENCY_UNIT + " (DEPRECATED)"},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "modifiedfee", "transaction fee with fee deltas used for mining priority (DEPRECATED)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "fee", "transaction fee, denominated in " + CURRENCY_UNIT + " (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "modifiedfee", "transaction fee with fee deltas used for mining priority, denominated in " + CURRENCY_UNIT + " (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
     RPCResult{RPCResult::Type::NUM_TIME, "time", "local time transaction entered pool in seconds since 1 Jan 1970 GMT"},
     RPCResult{RPCResult::Type::NUM, "height", "block height when transaction entered pool"},
     RPCResult{RPCResult::Type::NUM, "descendantcount", "number of in-mempool descendant transactions (including this one)"},
     RPCResult{RPCResult::Type::NUM, "descendantsize", "virtual transaction size of in-mempool descendants (including this one)"},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "descendantfees", "modified fees (see above) of in-mempool descendants (including this one) (DEPRECATED)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "descendantfees", "transaction fees of in-mempool descendants (including this one) with fee deltas used for mining priority, denominated in " + CURRENCY_ATOM + "s (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
     RPCResult{RPCResult::Type::NUM, "ancestorcount", "number of in-mempool ancestor transactions (including this one)"},
     RPCResult{RPCResult::Type::NUM, "ancestorsize", "virtual transaction size of in-mempool ancestors (including this one)"},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "ancestorfees", "modified fees (see above) of in-mempool ancestors (including this one) (DEPRECATED)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "ancestorfees", "transaction fees of in-mempool ancestors (including this one) with fee deltas used for mining priority, denominated in " + CURRENCY_ATOM + "s (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
     RPCResult{RPCResult::Type::STR_HEX, "wtxid", "hash of serialized transaction, including witness data"},
     RPCResult{RPCResult::Type::OBJ, "fees", "",
         {
-            RPCResult{RPCResult::Type::STR_AMOUNT, "base", "transaction fee in " + CURRENCY_UNIT},
-            RPCResult{RPCResult::Type::STR_AMOUNT, "modified", "transaction fee with fee deltas used for mining priority in " + CURRENCY_UNIT},
-            RPCResult{RPCResult::Type::STR_AMOUNT, "ancestor", "modified fees (see above) of in-mempool ancestors (including this one) in " + CURRENCY_UNIT},
-            RPCResult{RPCResult::Type::STR_AMOUNT, "descendant", "modified fees (see above) of in-mempool descendants (including this one) in " + CURRENCY_UNIT},
+            RPCResult{RPCResult::Type::STR_AMOUNT, "base", "transaction fee, denominated in " + CURRENCY_UNIT},
+            RPCResult{RPCResult::Type::STR_AMOUNT, "modified", "transaction fee with fee deltas used for mining priority, denominated in " + CURRENCY_UNIT},
+            RPCResult{RPCResult::Type::STR_AMOUNT, "ancestor", "transaction fees of in-mempool ancestors (including this one) with fee deltas used for mining priority, denominated in " + CURRENCY_UNIT},
+            RPCResult{RPCResult::Type::STR_AMOUNT, "descendant", "transaction fees of in-mempool descendants (including this one) with fee deltas used for mining priority, denominated in " + CURRENCY_UNIT},
         }},
     RPCResult{RPCResult::Type::ARR, "depends", "unconfirmed transactions used as inputs for this transaction",
         {RPCResult{RPCResult::Type::STR_HEX, "transactionid", "parent transaction id"}}},
@@ -494,26 +494,35 @@ static void entryToJSON(const CTxMemPool& pool, UniValue& info, const CTxMemPool
 {
     AssertLockHeld(pool.cs);
 
-    UniValue fees(UniValue::VOBJ);
-    fees.pushKV("base", ValueFromAmount(e.GetFee()));
-    fees.pushKV("modified", ValueFromAmount(e.GetModifiedFee()));
-    fees.pushKV("ancestor", ValueFromAmount(e.GetModFeesWithAncestors()));
-    fees.pushKV("descendant", ValueFromAmount(e.GetModFeesWithDescendants()));
-    info.pushKV("fees", fees);
-
     info.pushKV("vsize", (int)e.GetTxSize());
     info.pushKV("weight", (int)e.GetTxWeight());
-    info.pushKV("fee", ValueFromAmount(e.GetFee()));
-    info.pushKV("modifiedfee", ValueFromAmount(e.GetModifiedFee()));
+    // TODO: top-level fee fields are deprecated. deprecated_fee_fields_enabled blocks should be removed in v24
+    const bool deprecated_fee_fields_enabled{IsDeprecatedRPCEnabled("fees")};
+    if (deprecated_fee_fields_enabled) {
+        info.pushKV("fee", ValueFromAmount(e.GetFee()));
+        info.pushKV("modifiedfee", ValueFromAmount(e.GetModifiedFee()));
+    }
     info.pushKV("time", count_seconds(e.GetTime()));
     info.pushKV("height", (int)e.GetHeight());
     info.pushKV("descendantcount", e.GetCountWithDescendants());
     info.pushKV("descendantsize", e.GetSizeWithDescendants());
-    info.pushKV("descendantfees", e.GetModFeesWithDescendants());
+    if (deprecated_fee_fields_enabled) {
+        info.pushKV("descendantfees", e.GetModFeesWithDescendants());
+    }
     info.pushKV("ancestorcount", e.GetCountWithAncestors());
     info.pushKV("ancestorsize", e.GetSizeWithAncestors());
-    info.pushKV("ancestorfees", e.GetModFeesWithAncestors());
+    if (deprecated_fee_fields_enabled) {
+        info.pushKV("ancestorfees", e.GetModFeesWithAncestors());
+    }
     info.pushKV("wtxid", pool.vTxHashes[e.vTxHashesIdx].first.ToString());
+
+    UniValue fees(UniValue::VOBJ);
+    fees.pushKV("base", ValueFromAmount(e.GetFee()));
+    fees.pushKV("modified", ValueFromAmount(e.GetModifiedFee()));
+    fees.pushKV("ancestor", ValueFromAmount(e.GetModFeesWithAncestors()));
+    fees.pushKV("descendant", ValueFromAmount(e.GetModFeesWithDescendants()));
+    info.pushKV("fees", fees);
+
     const CTransaction& tx = e.GetTx();
     std::set<std::string> setDepends;
     for (const CTxIn& txin : tx.vin)