add error handling

Cargo.toml

@@ -17,7 +17,7 @@ members = [
 ]
 
 [workspace.dependencies]
-anyhow = "1.0"
+anyhow = "1.0.98"
 num_cpus = "1.13.1"
 openssl = { version = "0.10", features = ["vendored"] }
 openssl-probe = { version = "0.1.2" }
@@ -30,7 +30,7 @@ lazy_static = "1.5.0"
 env_logger = "0.10"
 log = "0.4"
 lru = "0.7.8"
-thiserror = "1.0"
+thiserror = "2.0.12"
 rs_merkle = "1.4"
 sha2 = "0.10.8"
 hex = "0.4.3"

nssa/Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+thiserror = "2.0.12"
 risc0-zkvm = "2.3.1"
 nssa-core = { path = "core"}
 program-methods = { path = "program_methods" }

nssa/core/src/program.rs

@@ -1,4 +1,3 @@
-
 use crate::account::{Account, AccountWithMetadata};
 
 pub type ProgramId = [u32; 8];
@@ -19,26 +18,26 @@ pub fn validate_constraints(
     pre_states: &[AccountWithMetadata],
     post_states: &[Account],
     executing_program_id: ProgramId,
-) -> Result<(), ()> {
+) -> bool {
     // 1. Lengths must match
     if pre_states.len() != post_states.len() {
-        return Err(());
+        return false;
     }
 
     for (pre, post) in pre_states.iter().zip(post_states) {
         // 2. Nonce must remain unchanged
         if pre.account.nonce != post.nonce {
-            return Err(());
+            return false;
         }
 
         // 3. Ownership change only allowed from default accounts
         if pre.account.program_owner != post.program_owner && pre.account != Account::default() {
-            return Err(());
+            return false;
         }
 
         // 4. Decreasing balance only allowed if owned by executing program
         if post.balance < pre.account.balance && pre.account.program_owner != executing_program_id {
-            return Err(());
+            return false;
         }
 
         // 5. Data changes only allowed if owned by executing program
@@ -46,7 +45,7 @@ pub fn validate_constraints(
             && (executing_program_id != pre.account.program_owner
                 || executing_program_id != post.program_owner)
         {
-            return Err(());
+            return false;
         }
     }
 
@@ -54,8 +53,8 @@ pub fn validate_constraints(
     let total_balance_pre_states: u128 = pre_states.iter().map(|pre| pre.account.balance).sum();
     let total_balance_post_states: u128 = post_states.iter().map(|post| post.balance).sum();
     if total_balance_pre_states != total_balance_post_states {
-        return Err(());
+        return false;
     }
 
-    Ok(())
+    true
 }

nssa/src/error.rs

@@ -0,0 +1,16 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum NssaError {
+    #[error("Invalid input: {0}")]
+    InvalidInput(String),
+
+    #[error("Operation failed")]
+    OperationFailed,
+
+    #[error("Risc0 error: {0}")]
+    ProgramExecutionFailed(String),
+
+    #[error("Program violated execution rules")]
+    InvalidProgramBehavior,
+}

nssa/src/lib.rs

@@ -6,6 +6,7 @@ use program_methods::{AUTHENTICATED_TRANSFER_ELF, AUTHENTICATED_TRANSFER_ID};
 use risc0_zkvm::{ExecutorEnv, ExecutorEnvBuilder, default_executor};
 
 mod address;
+pub mod error;
 pub mod public_transaction;
 mod signature;
 mod state;
@@ -18,6 +19,8 @@ pub use signature::PublicKey;
 pub use signature::Signature;
 pub use state::V01State;
 
+use crate::error::NssaError;
+
 pub const AUTHENTICATED_TRANSFER_PROGRAM: Program = Program {
     id: AUTHENTICATED_TRANSFER_ID,
     elf: AUTHENTICATED_TRANSFER_ELF,
@@ -28,10 +31,14 @@ fn write_inputs(
     pre_states: &[AccountWithMetadata],
     instruction_data: u128,
     env_builder: &mut ExecutorEnvBuilder,
-) -> Result<(), ()> {
+) -> Result<(), NssaError> {
     let pre_states = pre_states.to_vec();
-    env_builder.write(&pre_states).map_err(|_| ())?;
-    env_builder.write(&instruction_data).map_err(|_| ())?;
+    env_builder
+        .write(&pre_states)
+        .map_err(|e| NssaError::ProgramExecutionFailed(e.to_string()))?;
+    env_builder
+        .write(&instruction_data)
+        .map_err(|e| NssaError::ProgramExecutionFailed(e.to_string()))?;
     Ok(())
 }
 
@@ -39,7 +46,7 @@ fn execute_public(
     pre_states: &[AccountWithMetadata],
     instruction_data: u128,
     program: &Program,
-) -> Result<Vec<Account>, ()> {
+) -> Result<Vec<Account>, NssaError> {
     // Write inputs to the program
     let mut env_builder = ExecutorEnv::builder();
     write_inputs(pre_states, instruction_data, &mut env_builder)?;
@@ -47,10 +54,15 @@ fn execute_public(
 
     // Execute the program (without proving)
     let executor = default_executor();
-    let session_info = executor.execute(env, program.elf).map_err(|_| ())?;
+    let session_info = executor
+        .execute(env, program.elf)
+        .map_err(|e| NssaError::ProgramExecutionFailed(e.to_string()))?;
 
     // Get outputs
-    let mut post_states: Vec<Account> = session_info.journal.decode().map_err(|_| ())?;
+    let mut post_states: Vec<Account> = session_info
+        .journal
+        .decode()
+        .map_err(|e| NssaError::ProgramExecutionFailed(e.to_string()))?;
 
     // Claim any output account with default program owner field
     for account in post_states.iter_mut() {

nssa/src/state.rs

@@ -1,5 +1,5 @@
 use crate::{
-    AUTHENTICATED_TRANSFER_PROGRAM, address::Address, execute_public,
+    AUTHENTICATED_TRANSFER_PROGRAM, address::Address, error::NssaError, execute_public,
     public_transaction::PublicTransaction,
 };
 use nssa_core::{
@@ -40,10 +40,11 @@ impl V01State {
         }
     }
 
-    pub fn transition_from_public_transaction(&mut self, tx: &PublicTransaction) -> Result<(), ()> {
-        let state_diff = self
-            .execute_and_verify_public_transaction(tx)
-            .map_err(|_| ())?;
+    pub fn transition_from_public_transaction(
+        &mut self,
+        tx: &PublicTransaction,
+    ) -> Result<(), NssaError> {
+        let state_diff = self.execute_and_verify_public_transaction(tx)?;
 
         for (address, post) in state_diff.into_iter() {
             let current_account = self.get_account_by_address_mut(address);
@@ -71,17 +72,21 @@ impl V01State {
     fn execute_and_verify_public_transaction(
         &mut self,
         tx: &PublicTransaction,
-    ) -> Result<HashMap<Address, Account>, ()> {
+    ) -> Result<HashMap<Address, Account>, NssaError> {
         let message = tx.message();
         let witness_set = tx.witness_set();
 
         // All addresses must be different
         if message.addresses.iter().collect::<HashSet<_>>().len() != message.addresses.len() {
-            return Err(());
+            return Err(NssaError::InvalidInput(
+                "Duplicate addresses found in message".into(),
+            ));
         }
 
         if message.nonces.len() != witness_set.signatures_and_public_keys.len() {
-            return Err(());
+            return Err(NssaError::InvalidInput(
+                "Mismatch between number of nonces and signatures/public keys".into(),
+            ));
         }
 
         let mut authorized_addresses = Vec::new();
@@ -92,14 +97,16 @@ impl V01State {
         {
             // Check the signature is valid
             if !signature.is_valid_for(message, public_key) {
-                return Err(());
+                return Err(NssaError::InvalidInput(
+                    "Invalid signature for given message and public key".into(),
+                ));
             }
 
             // Check the nonce corresponds to the current nonce on the public state.
             let address = Address::from_public_key(public_key);
             let current_nonce = self.get_account_by_address(&address).nonce;
             if current_nonce != *nonce {
-                return Err(());
+                return Err(NssaError::InvalidInput("Nonce mismatch".into()));
             }
 
             authorized_addresses.push(address);
@@ -118,19 +125,16 @@ impl V01State {
         // Check the `program_id` corresponds to a built-in program
         // Only allowed program so far is the authenticated transfer program
         let Some(program) = self.builtin_programs.get(&message.program_id) else {
-            return Err(());
+            return Err(NssaError::InvalidInput("Unknown program".into()));
         };
 
         // // Execute program
-        let post_states =
-            execute_public(&pre_states, message.instruction_data, program).map_err(|_| ())?;
+        let post_states = execute_public(&pre_states, message.instruction_data, program)?;
 
         // Verify execution corresponds to a well-behaved program.
         // See the # Programs section for the definition of the `validate_constraints` method.
-        validate_constraints(&pre_states, &post_states, message.program_id).map_err(|_| ())?;
-
-        if post_states.len() != message.addresses.len() {
-            return Err(());
+        if !validate_constraints(&pre_states, &post_states, message.program_id) {
+            return Err(NssaError::InvalidProgramBehavior);
         }
 
         Ok(message.addresses.iter().cloned().zip(post_states).collect())

sequencer_core/src/lib.rs

@@ -94,7 +94,7 @@ impl SequencerCore {
     fn execute_check_transaction_on_state(
         &mut self,
         tx: nssa::PublicTransaction,
-    ) -> Result<nssa::PublicTransaction, ()> {
+    ) -> Result<nssa::PublicTransaction, nssa::error::NssaError> {
         self.store.state.transition_from_public_transaction(&tx)?;
 
         Ok(tx)
@@ -405,7 +405,7 @@ mod tests {
         // Signature is not from sender. Execution fails
         let result = sequencer.execute_check_transaction_on_state(tx);
 
-        assert!(matches!(result, Err(())));
+        assert!(matches!(result, Err(nssa::error::NssaError::ProgramExecutionFailed(_))));
     }
 
     #[test]
@@ -438,8 +438,7 @@ mod tests {
         let result = sequencer.execute_check_transaction_on_state(result.unwrap());
         let is_failed_at_balance_mismatch = matches!(
             result.err().unwrap(),
-            // TransactionMalformationErrorKind::BalanceMismatch { tx: _ }
-            ()
+            nssa::error::NssaError::ProgramExecutionFailed(_)
         );
 
         assert!(is_failed_at_balance_mismatch);