From f83d18b4a8e63c1850ab6df065b77a00c5d54985 Mon Sep 17 00:00:00 2001
From: raychu86 <14917648+raychu86@users.noreply.github.com>
Date: Tue, 12 Mar 2024 17:11:51 -0700
Subject: [PATCH] Move tx verification logic into check_speculate

---
 ledger/src/check_next_block.rs | 14 ++------------
 synthesizer/src/vm/finalize.rs | 16 +++++++++++++++-
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/ledger/src/check_next_block.rs b/ledger/src/check_next_block.rs
index c23797f8d4..ffb6213299 100644
--- a/ledger/src/check_next_block.rs
+++ b/ledger/src/check_next_block.rs
@@ -14,8 +14,6 @@
 
 use super::*;
 
-use rand::{rngs::StdRng, SeedableRng};
-
 impl<N: Network, C: ConsensusStorage<N>> Ledger<N, C> {
     /// Checks the given block is valid next block.
     pub fn check_next_block<R: CryptoRng + Rng>(&self, block: &Block<N>, rng: &mut R) -> Result<()> {
@@ -38,14 +36,6 @@ impl<N: Network, C: ConsensusStorage<N>> Ledger<N, C> {
             }
         }
 
-        // Ensure each transaction is well-formed and unique.
-        let transactions = block.transactions();
-        let rngs = (0..transactions.len()).map(|_| StdRng::from_seed(rng.gen())).collect::<Vec<_>>();
-        cfg_iter!(transactions).zip(rngs).try_for_each(|(transaction, mut rng)| {
-            self.check_transaction_basic(transaction, transaction.to_rejected_id()?, &mut rng)
-                .map_err(|e| anyhow!("Invalid transaction found in the transactions list: {e}"))
-        })?;
-
         // TODO (howardwu): Remove this after moving the total supply into credits.aleo.
         {
             // // Retrieve the latest total supply.
@@ -78,9 +68,9 @@ impl<N: Network, C: ConsensusStorage<N>> Ledger<N, C> {
             block.previous_hash(),
         )?;
 
-        // Ensure speculation over the unconfirmed transactions is correct.
+        // Ensure speculation over the unconfirmed transactions is correct and ensure each transaction is well-formed and unique.
         let ratified_finalize_operations =
-            self.vm.check_speculate(state, block.ratifications(), block.solutions(), block.transactions())?;
+            self.vm.check_speculate(state, block.ratifications(), block.solutions(), block.transactions(), rng)?;
 
         // Retrieve the committee lookback.
         let committee_lookback = {
diff --git a/synthesizer/src/vm/finalize.rs b/synthesizer/src/vm/finalize.rs
index a66a6f8065..216b8d13fb 100644
--- a/synthesizer/src/vm/finalize.rs
+++ b/synthesizer/src/vm/finalize.rs
@@ -20,6 +20,8 @@ use rand::{rngs::StdRng, SeedableRng};
 
 impl<N: Network, C: ConsensusStorage<N>> VM<N, C> {
     /// Speculates on the given list of transactions in the VM.
+    /// This function aborts all transactions that are not are well-formed or unique.
+    ///
     ///
     /// Returns the confirmed transactions, aborted transaction IDs,
     /// and finalize operations from pre-ratify and post-ratify.
@@ -111,18 +113,30 @@ impl<N: Network, C: ConsensusStorage<N>> VM<N, C> {
     }
 
     /// Checks the speculation on the given transactions in the VM.
+    /// This function also ensure that the given transactions are well-formed and unique.
     ///
     /// Returns the finalize operations from pre-ratify and post-ratify.
     #[inline]
-    pub fn check_speculate(
+    pub fn check_speculate<R: Rng + CryptoRng>(
         &self,
         state: FinalizeGlobalState,
         ratifications: &Ratifications<N>,
         solutions: &Solutions<N>,
         transactions: &Transactions<N>,
+        rng: &mut R,
     ) -> Result<Vec<FinalizeOperation<N>>> {
         let timer = timer!("VM::check_speculate");
 
+        // Ensure each transaction is well-formed and unique.
+        // NOTE: We perform the transaction checks here prior to `atomic_speculate` because we must
+        // ensure that the `Fee` transactions are valid. We can't unify the transaction checks in `atomic_speculate`
+        // because we run speculation on the unconfirmed variant of the transactions.
+        let rngs = (0..transactions.len()).map(|_| StdRng::from_seed(rng.gen())).collect::<Vec<_>>();
+        cfg_iter!(transactions).zip(rngs).try_for_each(|(transaction, mut rng)| {
+            self.check_transaction(transaction, transaction.to_rejected_id()?, &mut rng)
+                .map_err(|e| anyhow!("Invalid transaction found in the transactions list: {e}"))
+        })?;
+
         // Reconstruct the candidate ratifications to verify the speculation.
         let candidate_ratifications = ratifications.iter().cloned().collect::<Vec<_>>();
         // Reconstruct the unconfirmed transactions to verify the speculation.