feat: 7 bit long note_type_id (#10951)

noir-projects/aztec-nr/aztec/src/macros/notes/mod.nr

@@ -19,19 +19,19 @@ comptime global NOTE_HEADER_TYPE: Type = type_of(NoteHeader::empty());
 pub comptime mut global NOTES: UHashMap<Type, (StructDefinition, u32, Field, [(Quoted, u32, bool)]), BuildHasherDefault<Poseidon2Hasher>> =
     UHashMap::default();
 
-/// Computes a note type id by hashing a note name (e.g. `TokenNote`), getting the first 4 bytes of the hash
-/// and returning it as a `Field`.
-comptime fn compute_note_type_id(name: Quoted) -> Field {
-    let (name_as_str_quote, _) = name.as_str_quote();
+pub comptime mut global NOTE_TYPE_ID_COUNTER: u32 = 0;
+
+/// The note type id is set by enumerating the note types.
+comptime fn get_next_note_type_id() -> Field {
+    // We assert that the note type id fits within 7 bits
+    assert(
+        NOTE_TYPE_ID_COUNTER < 128 as u32,
+        "A contract can contain at most 128 different note types",
+    );
 
-    unquote!(
-        quote {
-            let bytes = $name_as_str_quote.as_bytes();
-            let hash = protocol_types::hash::poseidon2_hash_bytes(bytes);
-            let hash_bytes = hash.to_be_bytes::<4>();
-            protocol_types::utils::field::field_from_bytes(hash_bytes, true)
-        },
-    )
+    let note_type_id = NOTE_TYPE_ID_COUNTER as Field;
+    NOTE_TYPE_ID_COUNTER += 1;
+    note_type_id
 }
 
 /// Generates default `NoteInterface` implementation for a given note struct `s` and returns it as quote along with
@@ -123,6 +123,7 @@ comptime fn generate_note_interface(
                 let mut buffer: [u8; $content_len * 32 + 64] = [0; $content_len * 32 + 64];
 
                 let storage_slot_bytes: [u8; 32] = storage_slot.to_be_bytes();
+                // TODO(#10952): The following can be reduced to 7 bits
                 let note_type_id_bytes: [u8; 32] = $name::get_note_type_id().to_be_bytes();
 
                 for i in 0..32 {
@@ -265,7 +266,7 @@ pub(crate) comptime fn generate_note_export(
     let mut hasher = Poseidon2Hasher::default();
     s.as_type().hash(&mut hasher);
     let hash = hasher.finish() as u32;
-    let global_export_name = f"{name}_{hash}_EXPORTS".quoted_contents();
+    let global_export_name = f"{name}_EXPORTS_{hash}".quoted_contents();
     let note_fields_name = f"{name}Fields_{hash}".quoted_contents();
     let (note_name_as_str, _) = name.as_str_quote();
     let note_name_str_len = unquote!(quote { $note_name_as_str.as_bytes().len() });
@@ -871,7 +872,7 @@ pub comptime fn partial_note(s: StructDefinition, nullable_fields: [Quoted]) ->
     inject_note_header(s);
 
     let note_properties = generate_note_properties(s);
-    let note_type_id = compute_note_type_id(s.name());
+    let note_type_id = get_next_note_type_id();
     let (setup_payload_impl, setup_payload_name) =
         generate_setup_payload(s, indexed_fixed_fields, indexed_nullable_fields);
     let (finalization_payload_impl, finalization_payload_name) =
@@ -914,7 +915,7 @@ pub comptime fn note(s: StructDefinition) -> Quoted {
     inject_note_header(s);
 
     let note_properties = generate_note_properties(s);
-    let note_type_id = compute_note_type_id(s.name());
+    let note_type_id = get_next_note_type_id();
     let (note_interface_impl, note_serialized_len) = generate_note_interface(
         s,
         note_type_id,
@@ -944,7 +945,7 @@ pub comptime fn note_custom_interface(s: StructDefinition) -> Quoted {
     inject_note_header(s);
 
     let note_properties = generate_note_properties(s);
-    let note_type_id = compute_note_type_id(s.name());
+    let note_type_id = get_next_note_type_id();
     let serialized_len_type = fresh_type_variable();
     let note_interface_impl = s.as_type().get_trait_impl(
         quote { crate::note::note_interface::NoteInterface<$serialized_len_type> }

noir-projects/aztec-nr/aztec/src/macros/storage/mod.nr

@@ -3,6 +3,8 @@ use std::{collections::umap::UHashMap, hash::{BuildHasherDefault, poseidon2::Pos
 use super::utils::get_serialized_size;
 use super::utils::is_note;
 
+/// Stores a map from a module to the name of the struct that describes its storage layout.
+/// This is then used when generating a `storage_layout()` getter on the contract struct.
 pub comptime mut global STORAGE_LAYOUT_NAME: UHashMap<Module, Quoted, BuildHasherDefault<Poseidon2Hasher>> =
     UHashMap::default();
 

noir-projects/noir-contracts/contracts/test_contract/Nargo.toml

@@ -7,4 +7,5 @@ type = "contract"
 [dependencies]
 aztec = { path = "../../../aztec-nr/aztec" }
 value_note = { path = "../../../aztec-nr/value-note" }
+uint_note = { path = "../../../aztec-nr/uint-note" }
 token_portal_content_hash_lib = { path = "../token_portal_content_hash_lib" }

noir-projects/noir-contracts/contracts/test_contract/src/main.nr

@@ -1,10 +1,13 @@
+mod test;
 mod test_note;
 
 // A contract used for testing a random hodgepodge of small features from simulator and end-to-end tests.
 use dep::aztec::macros::aztec;
 
 #[aztec]
 contract Test {
+    // Note: If you import a new kind of note you will most likely need to update the test_note_type_id test
+    // as the note type ids of current notes might have changed.
 
     use dep::aztec::encrypted_logs::encrypted_event_emission::encode_and_encrypt_event_unconstrained;
     use dep::aztec::encrypted_logs::encrypted_note_emission::encode_and_encrypt_note;
@@ -43,6 +46,10 @@ contract Test {
     use std::meta::derive;
 
     use crate::test_note::TestNote;
+
+    // Imported just to test note type ids
+    use dep::uint_note::uint_note::UintNote;
+
     #[derive(Serialize)]
     #[event]
     struct ExampleEvent {

noir-projects/noir-contracts/contracts/test_contract/src/test.nr

@@ -0,0 +1,12 @@
+use crate::test_note::TestNote;
+use dep::uint_note::uint_note::UintNote;
+use dep::value_note::value_note::ValueNote;
+
+#[test]
+unconstrained fn test_note_type_id() {
+    // The order in which the note types are sorted seems arbitrary and an implementation detail of Noir,
+    // but the important thing is that they are sequential and start from 0.
+    assert_eq(UintNote::get_note_type_id(), 0, "UintNote type id should be 0");
+    assert_eq(ValueNote::get_note_type_id(), 1, "ValueNote type id should be 1");
+    assert_eq(TestNote::get_note_type_id(), 2, "TestNote type id should be 2");
+}

yarn-project/circuit-types/src/interfaces/pxe.ts

@@ -388,7 +388,7 @@ export interface PXE {
   isContractInitialized(address: AztecAddress): Promise<boolean>;
 
   /**
-   * Returns the enctypred events given search parameters.
+   * Returns the encrypted events given search parameters.
    * @param eventMetadata - Metadata of the event. This should be the class generated from the contract. e.g. Contract.events.Event
    * @param from - The block number to search from.
    * @param limit - The amount of blocks to search.

yarn-project/foundation/src/abi/note_selector.ts

@@ -1,6 +1,6 @@
 import { toBigIntBE } from '../bigint-buffer/index.js';
-import { randomBytes } from '../crypto/index.js';
-import { type Fr } from '../fields/fields.js';
+import { randomInt } from '../crypto/index.js';
+import { Fr } from '../fields/fields.js';
 import { hexSchemaFor } from '../schemas/utils.js';
 import { BufferReader } from '../serialize/buffer_reader.js';
 import { TypeRegistry } from '../serialize/type_registry.js';
@@ -14,7 +14,10 @@ export interface NoteSelector {
   _branding: 'NoteSelector';
 }
 
-/** A note selector is the first 4 bytes of the hash of a note signature. */
+/**
+ * A note selector is a 7 bit long value that identifies a note type within a contract.
+ * TODO(#10952): Encoding of note type id can be reduced to 7 bits.
+ */
 export class NoteSelector extends Selector {
   /**
    * Deserializes from a buffer or reader, corresponding to a write in cpp.
@@ -24,6 +27,9 @@ export class NoteSelector extends Selector {
   static fromBuffer(buffer: Buffer | BufferReader) {
     const reader = BufferReader.asReader(buffer);
     const value = Number(toBigIntBE(reader.readBytes(Selector.SIZE)));
+    if (value >= 1 << 7) {
+      throw new Error('Invalid note selector');
+    }
     return new NoteSelector(value);
   }
 
@@ -55,7 +61,8 @@ export class NoteSelector extends Selector {
    * @returns A random selector.
    */
   static random() {
-    return NoteSelector.fromBuffer(randomBytes(Selector.SIZE));
+    const value = randomInt(1 << 7);
+    return NoteSelector.fromField(new Fr(value));
   }
 
   toJSON() {