Fix last iteration in sequential opcode

CHANGELOG.md

@@ -36,6 +36,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [2369](https://github.com/FuelLabs/fuel-core/pull/2369): The `transaction_insertion_time_in_thread_pool_milliseconds` metric is properly collected.
 - [2413](https://github.com/FuelLabs/fuel-core/issues/2413): block production immediately errors if unable to lock the mutex.
 - [2389](https://github.com/FuelLabs/fuel-core/pull/2389): Fix construction of reverse iterator in RocksDB.
+- [2479](https://github.com/FuelLabs/fuel-core/pull/2479): Fix an error on the last iteration of the read and write sequential opcodes on contract storage.
 - [2478](https://github.com/FuelLabs/fuel-core/pull/2478): Fix proof created by `message_receipts_proof` function by ignoring the receipts from failed transactions to match `message_outbox_root`.
 - [2485](https://github.com/FuelLabs/fuel-core/pull/2485): Hardcode the timestamp of the genesis block and version of `tai64` to avoid breaking changes for us.
 

crates/storage/src/vm_storage.rs

@@ -344,11 +344,13 @@ where
         let mut state_key = Bytes32::zeroed();
 
         let mut results = Vec::new();
-        for _ in 0..range {
+        for i in 0..range {
+            if i != 0 {
+                key.increase()?;
+            }
             key.to_big_endian(state_key.as_mut());
             let multikey = ContractsStateKey::new(contract_id, &state_key);
             results.push(self.database.storage::<ContractsState>().get(&multikey)?);
-            key.increase()?;
         }
         Ok(results)
     }
@@ -367,12 +369,15 @@ where
 
         // verify key is in range
         current_key
-            .checked_add(U256::from(values.len()))
+            .checked_add(U256::from(values.len().saturating_sub(1)))
             .ok_or_else(|| anyhow!("range op exceeded available keyspace"))?;
 
         let mut key_bytes = Bytes32::zeroed();
         let mut found_unset = 0u32;
-        for value in values {
+        for (idx, value) in values.iter().enumerate() {
+            if idx != 0 {
+                current_key.increase()?;
+            }
             current_key.to_big_endian(key_bytes.as_mut());
 
             let option = self
@@ -385,8 +390,6 @@ where
                     .checked_add(1)
                     .expect("We've checked it above via `values.len()`");
             }
-
-            current_key.increase()?;
         }
 
         Ok(found_unset as usize)
@@ -403,7 +406,10 @@ where
         let mut current_key = U256::from_big_endian(start_key.as_ref());
 
         let mut key_bytes = Bytes32::zeroed();
-        for _ in 0..range {
+        for i in 0..range {
+            if i != 0 {
+                current_key.increase()?;
+            }
             current_key.to_big_endian(key_bytes.as_mut());
 
             let option = self
@@ -412,8 +418,6 @@ where
                 .take(&(contract_id, &key_bytes).into())?;
 
             found_unset |= option.is_none();
-
-            current_key.increase()?;
         }
 
         if found_unset {

tests/tests/vm_storage.rs

@@ -86,6 +86,11 @@ mod tests {
     => Err(())
     ; "read fails on partially initialized range if keyspace exceeded"
     )]
+    #[test_case(
+    &[(*u256_to_bytes32(U256::MAX), vec![0; 32])], *u256_to_bytes32(U256::MAX), 1
+    => Ok(vec![Some(vec![0; 32])])
+    ; "read success when reading last key"
+    )]
     fn read_sequential_range(
         prefilled_slots: &[([u8; 32], Vec<u8>)],
         start_key: [u8; 32],
@@ -161,6 +166,11 @@ mod tests {
     => Err(())
     ; "insert fails if start_key + range > u256::MAX"
     )]
+    #[test_case(
+    &[(*u256_to_bytes32(U256::MAX), vec![0; 32])], *u256_to_bytes32(U256::MAX), &[vec![1; 32]]
+    => Ok(true)
+    ; "try to modify only the last value of storage"
+    )]
     fn insert_range(
         prefilled_slots: &[([u8; 32], Vec<u8>)],
         start_key: [u8; 32],
@@ -255,6 +265,11 @@ mod tests {
     => (vec![], false)
     ; "remove multiple slots over partially uninitialized middle range"
     )]
+    #[test_case(
+    &[(*u256_to_bytes32(U256::MAX), vec![0; 32])], *u256_to_bytes32(U256::MAX), 1
+    => (vec![], true)
+    ; "try to modify only the last value of storage"
+    )]
     fn remove_range(
         prefilled_slots: &[([u8; 32], Vec<u8>)],
         start_key: [u8; 32],