refactor!: reimplement partial notes on FactStore (#24369)

Closes F-771

---------

Co-authored-by: Nicolas Chamo <nicolas@chamo.com.ar>

Author: mverzilli

docs/docs-developers/docs/resources/migration_notes.md

@@ -9,6 +9,31 @@ Aztec is in active development. Each version may introduce breaking changes that
 
 ## TBD
 
+### [Aztec.nr] `MessageContext` removed: message processing uses `ResolvedTx`
+
+`aztec::messages::processing::MessageContext` has been removed in favor of the new `ResolvedTx`, which carries the same `tx_hash`, `unique_note_hashes_in_tx`, and `first_nullifier_in_tx`, plus `block_number` and `block_hash`. The offchain handoff type `OffchainMessageWithContext` is likewise renamed to `OffchainMessageWithTx`.
+
+This affects contracts that implement a custom message handler (registered via `AztecConfig::custom_message_handler`): the handler's context parameter is now a `ResolvedTx`.
+
+**Migration:**
+
+```diff
+  use aztec::messages::processing::{
+-     enqueue_event_for_validation, MessageContext,
++     enqueue_event_for_validation, ResolvedTx,
+  };
+
+  unconstrained fn handle_my_message(
+      // ...
+-     message_context: MessageContext,
++     resolved_tx: ResolvedTx,
+      scope: AztecAddress,
+  ) {
+-     // ...message_context.tx_hash...
++     // ...resolved_tx.tx_hash...
+  }
+```
+
 ### [PXE] `pxe.updateContract` removed and `pxe.registerContract` no longer takes an artifact
 
 Registering classes and instances are now separate, unvalidated operations. `registerContractClass(artifact)` registers a class, `registerContract(instance)` registers an instance and no longer takes an artifact. `registerContract` does not check that PXE knows the contract's artifact: a missing artifact surfaces only when the contract is later simulated.

noir-projects/aztec-nr/aztec/src/lib.nr

@@ -45,6 +45,7 @@ pub mod transient;
 pub mod event;
 pub mod facts;
 pub mod messages;
+pub(crate) mod partial_notes;
 pub use protocol_types as protocol;
 pub(crate) mod logging;
 pub mod utils;

noir-projects/aztec-nr/aztec/src/messages/discovery/mod.nr

@@ -4,10 +4,10 @@ use crate::messages::{
     delivery::handshake::{get_handshake_secrets, PROVIDED_SECRETS_ARRAY_BASE_SLOT},
     processing::provided_secret::ProvidedSecret,
 };
+use crate::partial_notes;
 use crate::protocol::address::AztecAddress;
 
 pub(crate) mod nonce_discovery;
-pub(crate) mod partial_notes;
 pub(crate) mod private_events;
 pub mod private_notes;
 pub mod process_message;
@@ -18,8 +18,8 @@ use crate::{
         encoding::MAX_MESSAGE_CONTENT_LEN,
         logs::note::MAX_NOTE_PACKED_LEN,
         processing::{
-            MessageContext, offchain::OffchainInboxSync, OffchainMessageWithContext,
-            pending_tagged_log::PendingTaggedLog, validate_and_store_enqueued_notes_and_events,
+            offchain::OffchainInboxSync, OffchainMessageWithTx, pending_tagged_log::PendingTaggedLog, ResolvedTx,
+            validate_and_store_enqueued_notes_and_events,
         },
     },
     oracle::message_processing,
@@ -108,7 +108,7 @@ pub type CustomMessageHandler = unconstrained fn(
 /* msg_type_id */ u64,
 /* msg_metadata */ u64,
 /* msg_content */ BoundedVec<Field, MAX_MESSAGE_CONTENT_LEN>,
-/* message_context */ MessageContext,
+/* resolved_tx */ ResolvedTx,
 /* scope */ AztecAddress);
 
 /// Custom state synchronization handler.
@@ -209,22 +209,22 @@ unconstrained fn sync_state_with_secrets(
 
     if offchain_inbox_sync.is_some() {
         let msgs = offchain_inbox_sync.unwrap()(contract_address, scope);
-        msgs.for_each(|_i, msg: OffchainMessageWithContext| {
+        msgs.for_each(|_i, msg: OffchainMessageWithTx| {
             process_message_ciphertext(
                 contract_address,
                 compute_note_hash,
                 compute_note_nullifier,
                 process_custom_message,
                 msg.message_ciphertext,
-                msg.message_context,
+                msg.resolved_tx,
                 scope,
             );
         });
     }
 
     // Then we process all pending partial notes, regardless of whether they were found in the current or previous
     // executions.
-    partial_notes::fetch_and_process_partial_note_completion_logs(
+    partial_notes::sync(
         contract_address,
         compute_note_hash,
         compute_note_nullifier,
@@ -264,7 +264,7 @@ mod test {
             // Mock the oracle call to return a known base slot, then populate an ephemeral
             // array at that slot so do_sync_state processes a non-empty log list.
             let base_slot = 42;
-            let mock = std::test::OracleMock::mock("aztec_utl_getPendingTaggedLogs");
+            let mock = std::test::OracleMock::mock("aztec_utl_getPendingTaggedLogsV2");
             let _ = mock.returns(base_slot);
 
             let logs: EphemeralArray<PendingTaggedLog> = EphemeralArray::at(base_slot);
@@ -281,6 +281,10 @@ mod test {
                 no_inbox_sync,
                 scope,
             );
+
+            // Guards against the mocked oracle name going stale: if sync stops calling it, the crafted empty log
+            // above is never consumed and the test silently stops covering the empty-payload path.
+            assert_eq(mock.times_called(), 1);
         });
     }