fix generated example entity id uniqueness

Author: YaroShkvorets

.changeset/swift-jobs-count.md

@@ -0,0 +1,5 @@
+---
+'@graphprotocol/graph-cli': patch
+---
+
+fix generated example entity id uniqueness

packages/cli/src/protocols/ethereum/scaffold/mapping.ts

@@ -11,7 +11,7 @@ export const generatePlaceholderHandlers = ({
   contractName: string;
 }) =>
   `
-  import { BigInt } from '@graphprotocol/graph-ts'
+  import { BigInt, Bytes } from '@graphprotocol/graph-ts'
   import { ${contractName}, ${events.map(event => event._alias)} }
     from '../generated/${contractName}/${contractName}'
   import { ExampleEntity } from '../generated/schema'
@@ -21,14 +21,15 @@ export const generatePlaceholderHandlers = ({
       index === 0
         ? `
     export function handle${event._alias}(event: ${event._alias}): void {
-      // Entities can be loaded from the store using a string ID; this ID
+      // Entities can be loaded from the store using an ID; this ID
       // needs to be unique across all entities of the same type
-      let entity = ExampleEntity.load(event.transaction.from)
+      const id = event.transaction.hash.concat(Bytes.fromByteArray(Bytes.fromBigInt(event.logIndex)));
+      let entity = ExampleEntity.load(id)
 
       // Entities only exist after they have been saved to the store;
       // \`null\` checks allow to create entities on demand
       if (!entity) {
-        entity = new ExampleEntity(event.transaction.from)
+        entity = new ExampleEntity(id)
 
         // Entity fields can be set using simple assignments
         entity.count = BigInt.fromI32(0)

packages/cli/src/scaffold/__snapshots__/ethereum.test.ts.snap

@@ -34,7 +34,7 @@ dataSources:
 `;
 
 exports[`Ethereum subgraph scaffolding > Mapping (default) 1`] = `
-"import { BigInt } from "@graphprotocol/graph-ts"
+"import { BigInt, Bytes } from "@graphprotocol/graph-ts"
 import {
   Contract,
   ExampleEvent,
@@ -43,14 +43,17 @@ import {
 import { ExampleEntity } from "../generated/schema"
 
 export function handleExampleEvent(event: ExampleEvent): void {
-  // Entities can be loaded from the store using a string ID; this ID
+  // Entities can be loaded from the store using an ID; this ID
   // needs to be unique across all entities of the same type
-  let entity = ExampleEntity.load(event.transaction.from)
+  const id = event.transaction.hash.concat(
+    Bytes.fromByteArray(Bytes.fromBigInt(event.logIndex))
+  )
+  let entity = ExampleEntity.load(id)
 
   // Entities only exist after they have been saved to the store;
   // \`null\` checks allow to create entities on demand
   if (!entity) {
-    entity = new ExampleEntity(event.transaction.from)
+    entity = new ExampleEntity(id)
 
     // Entity fields can be set using simple assignments
     entity.count = BigInt.fromI32(0)