From 741fcca9b6e95e831a0a4a62b901558446c0d944 Mon Sep 17 00:00:00 2001
From: Etan Kissling <etan@status.im>
Date: Tue, 28 May 2024 08:38:57 +0200
Subject: [PATCH] Workaround for disallowed transaction superseding (#2181)

* Workaround for disallowed transaction superseding

The transaction spammer from Kurtosis keeps spamming transactions with
the same nonce because report 'pending' account nocne based on 'latest'
rather than actually considering the mempool. To avoid errors from
rejecting those, disable the required gas price bump when replacing
a transaction with a new nonce.

* Lint

* Skip superseding negative test
---
 nimbus/core/tx_pool/tx_tasks/tx_add.nim | 16 ++++++++++++----
 tests/test_txpool.nim                   | 11 ++++++-----
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/nimbus/core/tx_pool/tx_tasks/tx_add.nim b/nimbus/core/tx_pool/tx_tasks/tx_add.nim
index 01e95f087..b37fb814d 100644
--- a/nimbus/core/tx_pool/tx_tasks/tx_add.nim
+++ b/nimbus/core/tx_pool/tx_tasks/tx_add.nim
@@ -77,10 +77,18 @@ proc supersede(xp: TxPoolRef; item: TxItemRef): Result[void,TxInfo]
       return err(txInfoErrUnspecified)
     current = rc.value.data
 
-  # verify whether replacing is allowed, at all
-  let bumpPrice = (current.tx.gasPrice * xp.priceBump.GasInt + 99) div 100
-  if item.tx.gasPrice < current.tx.gasPrice + bumpPrice:
-    return err(txInfoErrReplaceUnderpriced)
+  # TODO: To unblock `kurtosis-tech/ethereum-package` based testing,
+  # we have to accept superseding transactions temporarily until `rpc_utils.nim`
+  # supports the 'pending' tag by incorporating pending transactions from the
+  # mempool when returning the current account nonce. Until that is fixed,
+  # we keep telling the transaction spammer that their nonce has not changed,
+  # and it keeps spamming transactions with the same nonce repeatedly.
+  # Note: When this is fixed, update `tests/test_txpool.nim` and
+  # re-enable the "Superseding txs with sender and nonce variants" test case.
+  if false:
+    let bumpPrice = (current.tx.gasPrice * xp.priceBump.GasInt + 99) div 100
+    if item.tx.gasPrice < current.tx.gasPrice + bumpPrice:
+      return err(txInfoErrReplaceUnderpriced)
 
   # make space, delete item
   if not xp.txDB.dispose(current, txInfoSenderNonceSuperseded):
diff --git a/tests/test_txpool.nim b/tests/test_txpool.nim
index 0e201c01b..a34a7d10b 100644
--- a/tests/test_txpool.nim
+++ b/tests/test_txpool.nim
@@ -301,11 +301,12 @@ proc runTxPoolTests(noisy = true) =
         check xq.nItems.total == testTxs.len
         check xq.nItems.disposed == testTxs.len
 
-        # last update item was underpriced, so it must not have been
-        # replaced
-        var altLst = testTxs.toSeq.mapIt("alt " & it[0].info)
-        altLst[^1] = testTxs[^1][0].info
-        check altLst.sorted == xq.toItems.toSeq.mapIt(it.info).sorted
+        if false:  # Temporarily disabled, see `supersede` in `tx_add.nim`
+          # last update item was underpriced, so it must not have been
+          # replaced
+          var altLst = testTxs.toSeq.mapIt("alt " & it[0].info)
+          altLst[^1] = testTxs[^1][0].info
+          check altLst.sorted == xq.toItems.toSeq.mapIt(it.info).sorted
 
       test &"Deleting tx => also delete higher nonces":