fix(tap-agent): derive allocation_id from V2 collection_id in AllocationId check

- Accept Horizon (V2) receipts that only provide collection_id by mapping the 32‑byte value to an Address
(last 20 bytes, right‑aligned).
- Preserve V1 behavior (use allocation_id() when present).
- Validate collection_id length and return a clear error when invalid.
- Add a small debug log comparing the resolved allocation_id to the expected one.

Author: neithanmo

crates/tap-agent/src/tap/context/checks/allocation_id.rs

@@ -8,7 +8,7 @@ use indexer_monitor::SubgraphClient;
 use indexer_query::{tap_transactions, TapTransactions};
 use indexer_watcher::new_watcher;
 use tap_core::receipt::checks::{Check, CheckError, CheckResult};
-use thegraph_core::alloy::primitives::Address;
+use thegraph_core::{alloy::primitives::Address, CollectionId as CollectionIdCore};
 use tokio::sync::watch::Receiver;
 
 use crate::tap::{CheckingReceipt, TapReceipt};
@@ -54,13 +54,33 @@ impl Check<TapReceipt> for AllocationId {
         _: &tap_core::receipt::Context,
         receipt: &CheckingReceipt,
     ) -> CheckResult {
-        let allocation_id = receipt
-            .signed_receipt()
-            .allocation_id()
-            .ok_or_else(|| CheckError::Failed(anyhow!("Receipt does not have an allocation_id")))?;
+        // Support both Legacy (V1) and Horizon (V2) receipts.
+        // V1 provides allocation_id directly; V2 provides collection_id which we map to an Address.
+        let allocation_id = if let Some(a) = receipt.signed_receipt().allocation_id() {
+            a
+        } else if let Some(cid) = receipt.signed_receipt().collection_id() {
+            // V2: collection_id is 32 bytes with the 20-byte address right-aligned (left-padded zeros).
+            let bytes = cid.as_slice();
+            if bytes.len() != 32 {
+                return Err(CheckError::Failed(anyhow!(
+                    "Invalid collection_id length: {} (expected 32)",
+                    bytes.len()
+                )));
+            }
+            Address::from_slice(&bytes[12..32])
+        } else {
+            return Err(CheckError::Failed(anyhow!(
+                "Receipt does not have an allocation_id or collection_id"
+            )));
+        };
         // TODO: Remove the if block below? Each TAP Monitor is specific to an allocation
         // ID. So the receipts that are received here should already have been filtered by
         // allocation ID.
+        tracing::debug!(
+            "Checking allocation_id: {:?} against expected_allocation_id: {}",
+            allocation_id,
+            self.allocation_id
+        );
         if allocation_id != self.allocation_id {
             return Err(CheckError::Failed(anyhow!("Receipt allocation_id different from expected: allocation_id: {:?}, expected_allocation_id: {}", allocation_id, self.allocation_id)));
         };