fix: enforce correct length of hashConstructor args

circuits/cpp/src/aztec3/circuits/abis/combined_historic_tree_roots.hpp

@@ -25,7 +25,8 @@ template <typename NCT> struct CombinedHistoricTreeRoots {
                public_data_tree_root == other.public_data_tree_root;
     };
 
-    template <typename Composer> CombinedHistoricTreeRoots<CircuitTypes<Composer>> to_circuit_type(Composer& composer) const
+    template <typename Composer>
+    CombinedHistoricTreeRoots<CircuitTypes<Composer>> to_circuit_type(Composer& composer) const
     {
         static_assert((std::is_same<NativeTypes, NCT>::value));
 
@@ -80,7 +81,8 @@ template <typename NCT> void write(std::vector<uint8_t>& buf, CombinedHistoricTr
     write(buf, historic_tree_roots.public_data_tree_root);
 };
 
-template <typename NCT> std::ostream& operator<<(std::ostream& os, CombinedHistoricTreeRoots<NCT> const& historic_tree_roots)
+template <typename NCT>
+std::ostream& operator<<(std::ostream& os, CombinedHistoricTreeRoots<NCT> const& historic_tree_roots)
 {
     return os << "private_historic_tree_roots: " << historic_tree_roots.private_historic_tree_roots << "\n"
               << "public_data_tree_root: " << historic_tree_roots.public_data_tree_root << "\n";

circuits/cpp/src/aztec3/circuits/abis/private_historic_tree_roots.hpp

@@ -27,7 +27,8 @@ template <typename NCT> struct PrivateHistoricTreeRoots {
                private_kernel_vk_tree_root == other.private_kernel_vk_tree_root;
     };
 
-    template <typename Composer> PrivateHistoricTreeRoots<CircuitTypes<Composer>> to_circuit_type(Composer& composer) const
+    template <typename Composer>
+    PrivateHistoricTreeRoots<CircuitTypes<Composer>> to_circuit_type(Composer& composer) const
     {
         static_assert((std::is_same<NativeTypes, NCT>::value));
 
@@ -90,7 +91,8 @@ template <typename NCT> void write(std::vector<uint8_t>& buf, PrivateHistoricTre
     write(buf, historic_tree_roots.private_kernel_vk_tree_root);
 };
 
-template <typename NCT> std::ostream& operator<<(std::ostream& os, PrivateHistoricTreeRoots<NCT> const& historic_tree_roots)
+template <typename NCT>
+std::ostream& operator<<(std::ostream& os, PrivateHistoricTreeRoots<NCT> const& historic_tree_roots)
 {
     return os << "private_data_tree_root: " << historic_tree_roots.private_data_tree_root << "\n"
               << "nullifier_tree_root: " << historic_tree_roots.nullifier_tree_root << "\n"

circuits/cpp/src/aztec3/circuits/kernel/private/.test.cpp

@@ -339,7 +339,7 @@ PrivateInputs<NT> do_private_call_get_kernel_inputs(bool const is_constructor,
     mock_previous_kernel.public_inputs.end.private_call_stack = initial_kernel_private_call_stack;
     mock_previous_kernel.public_inputs.constants = CombinedConstantData<NT>{
         .historic_tree_roots =
-            CombinedHistoricTreeRoots<NT> {
+            CombinedHistoricTreeRoots<NT>{
                 .private_historic_tree_roots =
                     PrivateHistoricTreeRoots<NT>{
                         .private_data_tree_root = private_circuit_public_inputs.historic_private_data_tree_root,

circuits/cpp/src/aztec3/circuits/kernel/private/native_private_kernel_circuit.cpp

@@ -144,7 +144,8 @@ void contract_logic(DummyComposer& composer,
     auto const& purported_contract_tree_root =
         private_inputs.private_call.call_stack_item.public_inputs.historic_contract_tree_root;
     auto const& previous_kernel_contract_tree_root =
-        private_inputs.previous_kernel.public_inputs.constants.historic_tree_roots.private_historic_tree_roots.contract_tree_root;
+        private_inputs.previous_kernel.public_inputs.constants.historic_tree_roots.private_historic_tree_roots
+            .contract_tree_root;
     composer.do_assert(purported_contract_tree_root == previous_kernel_contract_tree_root,
                        "purported_contract_tree_root doesn't match previous_kernel_contract_tree_root");
 

circuits/cpp/src/aztec3/circuits/rollup/base/.test.cpp

@@ -693,7 +693,8 @@ TEST_F(base_rollup_tests, native_compute_membership_historic_private_data)
         .root = tree.root(),
         .next_available_leaf_index = 0,
     };
-    inputs.kernel_data[0].public_inputs.constants.historic_tree_roots.private_historic_tree_roots.private_data_tree_root = fr(0);
+    inputs.kernel_data[0]
+        .public_inputs.constants.historic_tree_roots.private_historic_tree_roots.private_data_tree_root = fr(0);
 
     // fetch sibling path from hash path (only get the second half of the hash path)
     auto hash_path = tree.get_hash_path(0);

circuits/cpp/src/aztec3/circuits/rollup/base/native_base_rollup_circuit.cpp

@@ -201,8 +201,9 @@ void perform_historical_private_data_tree_membership_checks(DummyComposer& compo
     auto historic_root = baseRollupInputs.constants.start_tree_of_historic_private_data_tree_roots_snapshot.root;
 
     for (size_t i = 0; i < 2; i++) {
-        NT::fr leaf = baseRollupInputs.kernel_data[i]
-                          .public_inputs.constants.historic_tree_roots.private_historic_tree_roots.private_data_tree_root;
+        NT::fr leaf =
+            baseRollupInputs.kernel_data[i]
+                .public_inputs.constants.historic_tree_roots.private_historic_tree_roots.private_data_tree_root;
         abis::MembershipWitness<NT, PRIVATE_DATA_TREE_ROOTS_TREE_HEIGHT> historic_root_witness =
             baseRollupInputs.historic_private_data_tree_root_membership_witnesses[i];
 

yarn-project/circuits.js/src/abis/__snapshots__/abis.test.ts.snap

@@ -99,41 +99,81 @@ Fr {
 }
 `;
 
-exports[`abis wasm bindings hash constructor info 1`] = `
+exports[`abis wasm bindings hash constructor info (max args) 1`] = `
 {
   "data": [
-    36,
-    203,
-    121,
-    198,
-    238,
-    246,
-    39,
     11,
-    209,
-    251,
-    234,
-    135,
-    70,
-    0,
-    68,
-    226,
-    184,
-    31,
-    77,
+    83,
     126,
-    81,
-    123,
-    23,
-    198,
-    162,
-    185,
-    199,
-    254,
+    59,
+    216,
+    223,
+    139,
+    197,
+    97,
+    118,
+    93,
+    86,
+    72,
+    166,
+    146,
     183,
-    90,
-    167,
+    120,
+    217,
+    74,
+    66,
+    45,
+    248,
+    192,
+    209,
+    59,
+    200,
+    244,
+    214,
+    63,
+    239,
+    67,
+    177,
+  ],
+  "type": "Buffer",
+}
+`;
+
+exports[`abis wasm bindings hash constructor info 2 args 1`] = `
+{
+  "data": [
+    6,
+    8,
+    191,
+    65,
+    136,
+    96,
+    198,
+    140,
+    203,
+    137,
+    102,
+    172,
+    105,
+    89,
+    77,
+    15,
+    15,
+    196,
+    42,
+    213,
+    11,
+    179,
     9,
+    133,
+    16,
+    68,
+    18,
+    76,
+    208,
+    143,
+    149,
+    123,
   ],
   "type": "Buffer",
 }

yarn-project/circuits.js/src/abis/abis.test.ts

@@ -1,4 +1,4 @@
-import { Fr, FunctionData, FunctionLeafPreimage, NewContractData } from '../index.js';
+import { ARGS_LENGTH, Fr, FunctionData, FunctionLeafPreimage, NewContractData } from '../index.js';
 import { makeEthAddress } from '../tests/factories.js';
 import { makeAztecAddress, makeBytes, makeTxRequest, makeVerificationKey } from '../tests/factories.js';
 import { CircuitsWasm } from '../wasm/circuits_wasm.js';
@@ -66,15 +66,30 @@ describe('abis wasm bindings', () => {
     expect(res).toMatchSnapshot();
   });
 
-  it('hash constructor info', async () => {
+  it('hash constructor info 2 args', async () => {
     const functionData = new FunctionData(Buffer.alloc(4), true, true);
     // args needs to have a FIXED length of 8, due to a circuit constant `aztec3::ARGS_SIZE`.
-    const args = [new Fr(0n), new Fr(1n), new Fr(0n), new Fr(1n), new Fr(0n), new Fr(1n), new Fr(0n), new Fr(1n)];
+    const args = [new Fr(0n), new Fr(1n)];
     const vkHash = Buffer.alloc(32);
     const res = await hashConstructor(wasm, functionData, args, vkHash);
     expect(res).toMatchSnapshot();
   });
 
+  it('hash constructor info (max args)', async () => {
+    const functionData = new FunctionData(Buffer.alloc(4), true, true);
+    const args = Array.from({ length: ARGS_LENGTH }, (v, i) => new Fr(BigInt(i)));
+    const vkHash = Buffer.alloc(32);
+    const res = await hashConstructor(wasm, functionData, args, vkHash);
+    expect(res).toMatchSnapshot();
+  });
+
+  it('hash constructor throws (>max args)', async () => {
+    const functionData = new FunctionData(Buffer.alloc(4), true, true);
+    const args = Array.from({ length: ARGS_LENGTH + 1 }, (v, i) => new Fr(BigInt(i)));
+    const vkHash = Buffer.alloc(32);
+    await expect(hashConstructor(wasm, functionData, args, vkHash)).rejects.toThrow();
+  });
+
   it('computes a contract address', async () => {
     const deployerAddr = makeAztecAddress(1);
     const contractAddrSalt = new Fr(2n);

yarn-project/circuits.js/src/abis/abis.ts

@@ -4,6 +4,7 @@ import { CircuitsWasm } from '../wasm/index.js';
 import {
   FunctionData,
   FUNCTION_SELECTOR_NUM_BYTES,
+  ARGS_LENGTH,
   TxRequest,
   NewContractData,
   FunctionLeafPreimage,
@@ -108,7 +109,13 @@ export async function hashConstructor(
   args: Fr[],
   constructorVKHash: Buffer,
 ) {
-  const inputVector = serializeToBuffer(args.map(fr => fr.toBuffer()));
+  if (args.length > ARGS_LENGTH) {
+    throw new Error(`Expected constructor args to have length <= ${ARGS_LENGTH}! Was: ${args.length}`);
+  }
+  const numEmptyArgs = ARGS_LENGTH - args.length;
+  const emptyArgs = Array.from({ length: numEmptyArgs }, () => new Fr(0n));
+  const fullArgs = args.concat(emptyArgs);
+  const inputVector = serializeToBuffer(fullArgs.map(fr => fr.toBuffer()));
   wasm.call('pedersen__init');
   const result = await inputBuffersToOutputBuffer(
     wasm,