feat: Simplify NoteMetadata constructor by making tag optional (0xMiden#2384)

* Update NoteMetadata::new API calls in miden-testing crate

Changed from NoteMetadata::new(sender, note_type, tag) to NoteMetadata::new(sender, note_type).with_tag(tag) across all files in the miden-testing crate.

Updated files:
- tests/agglayer/bridge_out.rs (2 occurrences)
- tests/agglayer/bridge_in.rs (1 occurrence)
- tests/scripts/faucet.rs (2 occurrences)
- tests/scripts/send_note.rs (2 occurrences)
- tests/scripts/swap.rs (1 occurrence)
- tests/lib.rs (1 occurrence)
- src/kernel_tests/tx/test_output_note.rs (3 occurrences)
- src/kernel_tests/tx/test_tx.rs (2 occurrences)
- src/kernel_tests/tx/test_account_interface.rs (1 occurrence)
- src/kernel_tests/tx/test_note.rs (2 occurrences)
- src/kernel_tests/tx/test_active_note.rs (1 occurrence)
- src/standards/network_account_target.rs (1 occurrence)

* Change NoteMetadata constructor to not take tag by default

- Modified NoteMetadata::new() to only take sender and note_type
- Added with_tag() method for setting tag explicitly
- Updated all call sites across protocol, testing, standards, tx, and agglayer crates
- Tag now defaults to NoteTag::default() if not explicitly set

Co-authored-by: mmagician <8402446+mmagician@users.noreply.github.com>

* Fix formatting and missed call site

Co-authored-by: mmagician <8402446+mmagician@users.noreply.github.com>

* Improve documentation for mutator methods

Co-authored-by: mmagician <8402446+mmagician@users.noreply.github.com>

* Add changelog entry for PR 0xMiden#2384

Co-authored-by: mmagician <8402446+mmagician@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: mmagician <8402446+mmagician@users.noreply.github.com>
Co-authored-by: Marti <marti@miden.team>

Author: 2 people

CHANGELOG.md

@@ -18,6 +18,7 @@ Enable `CodeBuilder` to add advice map entries to compiled scripts ([#2275](http
 
 - Removed redundant note storage item count from advice map ([#2376](https://github.com/0xMiden/miden-base/pull/2376)).
 - [BREAKING] Prefixed transaction kernel events with `miden::protocol` ([#2364](https://github.com/0xMiden/miden-base/pull/2364)).
+- [BREAKING] Simplified `NoteMetadata::new()` constructor to not require tag parameter; tag defaults to zero and can be set via `with_tag()` builder method ([#2384](https://github.com/0xMiden/miden-base/pull/2384)).
 - [BREAKING] Renamed `WellKnownComponent` to `StandardAccountComponent`, `WellKnownNote` to `StandardNote`, and `WellKnownNoteAttachment` to `StandardNoteAttachment` ([#2332](https://github.com/0xMiden/miden-base/pull/2332)).
 - Skip requests to the `DataStore` for asset vault witnesses which are already in transaction inputs ([#2298](https://github.com/0xMiden/miden-base/pull/2298)).
 - [BREAKING] Refactored `TransactionAuthenticator::get_public_key()` method to return `Arc<PublicKey> `instead of `&PublicKey` ([#2304](https://github.com/0xMiden/miden-base/pull/2304)).

crates/miden-agglayer/src/lib.rs

@@ -518,7 +518,8 @@ pub fn create_claim_note<R: FeltRng>(params: ClaimNoteParams<'_, R>) -> Result<N
             .map_err(|e| NoteError::other(e.to_string()))?
             .into();
     // Use a default sender since we don't have sender anymore - create from destination address
-    let metadata = NoteMetadata::new(params.claim_note_creator_account_id, note_type, tag)
+    let metadata = NoteMetadata::new(params.claim_note_creator_account_id, note_type)
+        .with_tag(tag)
         .with_attachment(attachment);
     let assets = NoteAssets::new(vec![])?;
     let recipient = NoteRecipient::new(serial_num, claim_script, inputs);

crates/miden-protocol/src/note/file.rs

@@ -171,7 +171,7 @@ mod tests {
         let recipient = NoteRecipient::new(serial_num, script, note_storage);
 
         let asset = Asset::Fungible(FungibleAsset::new(faucet, 100).unwrap());
-        let metadata = NoteMetadata::new(faucet, NoteType::Public, NoteTag::from(123));
+        let metadata = NoteMetadata::new(faucet, NoteType::Public).with_tag(NoteTag::from(123));
 
         Note::new(NoteAssets::new(vec![asset]).unwrap(), metadata, recipient)
     }

crates/miden-protocol/src/note/metadata.rs

@@ -77,11 +77,14 @@ impl NoteMetadata {
     // --------------------------------------------------------------------------------------------
 
     /// Returns a new [`NoteMetadata`] instantiated with the specified parameters.
-    pub fn new(sender: AccountId, note_type: NoteType, tag: NoteTag) -> Self {
+    ///
+    /// The tag defaults to [`NoteTag::default()`]. Use [`NoteMetadata::with_tag`] to set a
+    /// specific tag if needed.
+    pub fn new(sender: AccountId, note_type: NoteType) -> Self {
         Self {
             sender,
             note_type,
-            tag,
+            tag: NoteTag::default(),
             attachment: NoteAttachment::default(),
         }
     }
@@ -153,12 +156,27 @@ impl NoteMetadata {
     // MUTATORS
     // --------------------------------------------------------------------------------------------
 
-    /// Overwrites the note's attachment with the provided one.
+    /// Mutates the note's tag by setting it to the provided value.
+    pub fn set_tag(&mut self, tag: NoteTag) {
+        self.tag = tag;
+    }
+
+    /// Returns a new [`NoteMetadata`] with the tag set to the provided value.
+    ///
+    /// This is a builder method that consumes self and returns a new instance for method chaining.
+    pub fn with_tag(mut self, tag: NoteTag) -> Self {
+        self.tag = tag;
+        self
+    }
+
+    /// Mutates the note's attachment by setting it to the provided value.
     pub fn set_attachment(&mut self, attachment: NoteAttachment) {
         self.attachment = attachment;
     }
 
-    /// Overwrites the note's attachment with the provided one.
+    /// Returns a new [`NoteMetadata`] with the attachment set to the provided value.
+    ///
+    /// This is a builder method that consumes self and returns a new instance for method chaining.
     pub fn with_attachment(mut self, attachment: NoteAttachment) -> Self {
         self.attachment = attachment;
         self
@@ -184,7 +202,7 @@ impl Deserializable for NoteMetadata {
         let tag = NoteTag::read_from(source)?;
         let attachment = NoteAttachment::read_from(source)?;
 
-        Ok(NoteMetadata::new(sender, note_type, tag).with_attachment(attachment))
+        Ok(NoteMetadata::new(sender, note_type).with_tag(tag).with_attachment(attachment))
     }
 }
 
@@ -351,7 +369,8 @@ mod tests {
         let sender = AccountId::try_from(ACCOUNT_ID_MAX_ONES).unwrap();
         let note_type = NoteType::Public;
         let tag = NoteTag::new(u32::MAX);
-        let metadata = NoteMetadata::new(sender, note_type, tag).with_attachment(attachment);
+        let metadata =
+            NoteMetadata::new(sender, note_type).with_tag(tag).with_attachment(attachment);
 
         // Serialization Roundtrip
         let deserialized = NoteMetadata::read_from_bytes(&metadata.to_bytes())?;

crates/miden-protocol/src/testing/note.rs

@@ -24,11 +24,8 @@ impl Note {
         let note_script = NoteScript::mock();
         let assets =
             NoteAssets::new(vec![FungibleAsset::mock(200)]).expect("note assets should be valid");
-        let metadata = NoteMetadata::new(
-            sender_id,
-            NoteType::Private,
-            NoteTag::with_account_target(sender_id),
-        );
+        let metadata = NoteMetadata::new(sender_id, NoteType::Private)
+            .with_tag(NoteTag::with_account_target(sender_id));
         let inputs = NoteStorage::new(Vec::new()).unwrap();
         let recipient = NoteRecipient::new(serial_num, note_script, inputs);
 

crates/miden-standards/src/account/interface/test.rs

@@ -253,7 +253,7 @@ fn test_basic_wallet_custom_notes() {
     let sender_account_id = ACCOUNT_ID_REGULAR_PUBLIC_ACCOUNT_IMMUTABLE_CODE_2.try_into().unwrap();
     let serial_num = RpoRandomCoin::new(Word::from([1, 2, 3, 4u32])).draw_word();
     let tag = NoteTag::with_account_target(wallet_account.id());
-    let metadata = NoteMetadata::new(sender_account_id, NoteType::Public, tag);
+    let metadata = NoteMetadata::new(sender_account_id, NoteType::Public).with_tag(tag);
     let vault = NoteAssets::new(vec![FungibleAsset::mock(100)]).unwrap();
 
     let compatible_source_code = "
@@ -336,7 +336,7 @@ fn test_basic_fungible_faucet_custom_notes() {
     let sender_account_id = ACCOUNT_ID_REGULAR_PUBLIC_ACCOUNT_IMMUTABLE_CODE_2.try_into().unwrap();
     let serial_num = RpoRandomCoin::new(Word::from([1, 2, 3, 4u32])).draw_word();
     let tag = NoteTag::with_account_target(faucet_account.id());
-    let metadata = NoteMetadata::new(sender_account_id, NoteType::Public, tag);
+    let metadata = NoteMetadata::new(sender_account_id, NoteType::Public).with_tag(tag);
     let vault = NoteAssets::new(vec![FungibleAsset::mock(100)]).unwrap();
 
     let compatible_source_code = "
@@ -439,7 +439,7 @@ fn test_custom_account_custom_notes() {
 
     let serial_num = RpoRandomCoin::new(Word::from([1, 2, 3, 4u32])).draw_word();
     let tag = NoteTag::with_account_target(target_account.id());
-    let metadata = NoteMetadata::new(sender_account.id(), NoteType::Public, tag);
+    let metadata = NoteMetadata::new(sender_account.id(), NoteType::Public).with_tag(tag);
     let vault = NoteAssets::new(vec![FungibleAsset::mock(100)]).unwrap();
 
     let compatible_source_code = "
@@ -543,7 +543,7 @@ fn test_custom_account_multiple_components_custom_notes() {
 
     let serial_num = RpoRandomCoin::new(Word::from([1, 2, 3, 4u32])).draw_word();
     let tag = NoteTag::with_account_target(target_account.id());
-    let metadata = NoteMetadata::new(sender_account.id(), NoteType::Public, tag);
+    let metadata = NoteMetadata::new(sender_account.id(), NoteType::Public).with_tag(tag);
     let vault = NoteAssets::new(vec![FungibleAsset::mock(100)]).unwrap();
 
     let compatible_source_code = "

crates/miden-standards/src/note/burn.rs

@@ -99,7 +99,8 @@ impl BurnNote {
         let inputs = NoteStorage::new(vec![])?;
         let tag = NoteTag::with_account_target(faucet_id);
 
-        let metadata = NoteMetadata::new(sender, note_type, tag).with_attachment(attachment);
+        let metadata =
+            NoteMetadata::new(sender, note_type).with_tag(tag).with_attachment(attachment);
         let assets = NoteAssets::new(vec![fungible_asset])?; // BURN notes contain the asset to burn
         let recipient = NoteRecipient::new(serial_num, note_script, inputs);
 

crates/miden-standards/src/note/mint.rs

@@ -104,7 +104,8 @@ impl MintNote {
 
         let tag = NoteTag::with_account_target(faucet_id);
 
-        let metadata = NoteMetadata::new(sender, note_type, tag).with_attachment(attachment);
+        let metadata =
+            NoteMetadata::new(sender, note_type).with_tag(tag).with_attachment(attachment);
         let assets = NoteAssets::new(vec![])?; // MINT notes have no assets
         let recipient = NoteRecipient::new(serial_num, note_script, storage);
 

crates/miden-standards/src/note/p2id.rs

@@ -87,7 +87,8 @@ impl P2idNote {
 
         let tag = NoteTag::with_account_target(target);
 
-        let metadata = NoteMetadata::new(sender, note_type, tag).with_attachment(attachment);
+        let metadata =
+            NoteMetadata::new(sender, note_type).with_tag(tag).with_attachment(attachment);
         let vault = NoteAssets::new(assets)?;
 
         Ok(Note::new(vault, metadata, recipient))

crates/miden-standards/src/note/p2ide.rs

@@ -92,7 +92,8 @@ impl P2ideNote {
         let recipient = Self::build_recipient(target, reclaim_height, timelock_height, serial_num)?;
         let tag = NoteTag::with_account_target(target);
 
-        let metadata = NoteMetadata::new(sender, note_type, tag).with_attachment(attachment);
+        let metadata =
+            NoteMetadata::new(sender, note_type).with_tag(tag).with_attachment(attachment);
         let vault = NoteAssets::new(assets)?;
 
         Ok(Note::new(vault, metadata, recipient))