feature(subgraphs): Add creationTransactionHash to lock entity in subgraph

subgraph/schema.graphql

@@ -45,6 +45,8 @@ type Lock @entity {
   The primary reason for this role is to support additional purchase mechanisms beyond direct key purchases like credit-card purchases.
   """
   keyGranters: [Bytes!]!
+  "transaction hash of the lock's creation"
+  transactionHash: String!
 }
 
 type Key @entity {

subgraph/src/unlock.ts

@@ -1,6 +1,6 @@
 /* eslint-disable no-unused-vars */
 /* eslint-disable prefer-const */
-import { log, BigInt, ethereum } from '@graphprotocol/graph-ts'
+import { log, BigInt } from '@graphprotocol/graph-ts'
 import { NewLock, LockUpgraded, GNPChanged } from '../generated/Unlock/Unlock'
 import { PublicLock as PublicLockMerged } from '../generated/templates/PublicLock/PublicLock'
 import { PublicLock } from '../generated/templates'
@@ -105,6 +105,7 @@ export function handleNewLock(event: NewLock): void {
   lock.createdAtBlock = event.block.number
   lock.lastKeyMintedAt = null
   lock.lastKeyRenewedAt = null
+  lock.transactionHash = event.transaction.hash.toHexString()
 
   if (version.le(BigInt.fromI32(8))) {
     // prior to v8, add default lock manager

subgraph/tests/locks-utils.ts

@@ -35,6 +35,11 @@ export function createNewLockEvent(
 ): NewLock {
   const newLockEvent = changetype<NewLock>(newMockEvent())
 
+  // Set a deterministic transaction hash for testing
+  newLockEvent.transaction.hash = Bytes.fromHexString(
+    '0x0000000000000000000000000000000000000000000000000000000000000001'
+  )
+
   newLockEvent.parameters = []
 
   newLockEvent.parameters.push(

subgraph/tests/locks.test.ts

@@ -85,6 +85,12 @@ describe('Describe Locks events', () => {
     assert.entityCount('Lock', 1)
     assert.fieldEquals('Lock', lockAddress, 'address', lockAddress)
     assert.fieldEquals('Lock', lockAddress, 'createdAtBlock', '1')
+    assert.fieldEquals(
+      'Lock',
+      lockAddress,
+      'transactionHash',
+      '0x0000000000000000000000000000000000000000000000000000000000000001'
+    )
     assert.fieldEquals('Lock', lockAddress, 'version', '11')
     assert.fieldEquals('Lock', lockAddress, 'price', '1000')
     assert.fieldEquals('Lock', lockAddress, 'name', 'My lock graph')