graph init should only generate entity handlers for immutable enitites (#1993)

* Generate only immutable entities when using graph init with a source subgraph

* remove EntityHandler from codegen for composed subgraphs

* fix: clarify error message for source subgraph immutable entities requirement

* Add changeset

* remove non entity type test for getImmutableEntityNames

* remove graph-ts from changeset

Author: incrypto32

.changeset/short-coins-deny.md

@@ -0,0 +1,5 @@
+---
+'@graphprotocol/graph-cli': minor
+---
+
+Composed subgraphs are modified to only accept immutable entites as triggers from a source subgraph

packages/cli/src/commands/init.ts

@@ -1253,7 +1253,7 @@ async function initSubgraphFromContract(
     }
   }
 
-  let entities: string[] | undefined;
+  let immutableEntities: string[] | undefined;
 
   if (isComposedSubgraph) {
     try {
@@ -1274,7 +1274,14 @@ async function initSubgraphFromContract(
       startBlock ||= getMinStartBlock(manifestYaml)?.toString();
       const schemaString = await loadSubgraphSchemaFromIPFS(ipfsClient, source);
       const schema = await Schema.loadFromString(schemaString);
-      entities = schema.getEntityNames();
+      immutableEntities = schema.getImmutableEntityNames();
+
+      if (immutableEntities.length === 0) {
+        this.error(
+          'Source subgraph must have at least one immutable entity. This subgraph cannot be used as a source subgraph since it has no immutable entities.',
+          { exit: 1 },
+        );
+      }
     } catch (e) {
       this.error(`Failed to load and parse subgraph schema: ${e.message}`, { exit: 1 });
     }
@@ -1316,7 +1323,7 @@ async function initSubgraphFromContract(
           startBlock,
           node,
           spkgPath,
-          entities,
+          entities: immutableEntities,
         },
         spinner,
       );

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

@@ -7,12 +7,11 @@ export const generatePlaceholderHandlers = ({
 }) => `
 import { ExampleEntity } from '../generated/schema'
 import {${entities.join(', ')}} from '../generated/subgraph-${contract}'
-import { EntityTrigger } from '@graphprotocol/graph-ts'
 
 ${entities
   .map(
     entityName => `
-export function handle${entityName}(entity: EntityTrigger<${entityName}>): void {
+export function handle${entityName}(entity: ${entityName}): void {
   // Empty handler for ${entityName}
 }`,
   )

packages/cli/src/schema.test.ts

@@ -0,0 +1,44 @@
+import { beforeEach, describe, expect, test } from 'vitest';
+import Schema from './schema.js';
+
+describe('Schema', () => {
+  const schemaDocument = `
+    type Entity1 @entity {
+      id: ID!
+    }
+
+    type Entity2 @entity(immutable: true) {
+      id: ID!
+    }
+
+    type Entity3 @entity(immutable: false) {
+      id: ID!
+    }
+  `;
+
+  let schema: Schema;
+
+  beforeEach(async () => {
+    schema = await Schema.loadFromString(schemaDocument);
+  });
+
+  test('getEntityNames returns all entity types', () => {
+    const entityNames = schema.getEntityNames();
+    expect(entityNames).toEqual(['Entity1', 'Entity2', 'Entity3']);
+  });
+
+  test('getImmutableEntityNames returns only immutable entity types', () => {
+    const immutableEntityNames = schema.getImmutableEntityNames();
+    expect(immutableEntityNames).toEqual(['Entity2']);
+  });
+
+  test('getImmutableEntityNames handles entities without immutable flag', () => {
+    const immutableEntityNames = schema.getImmutableEntityNames();
+    expect(immutableEntityNames).not.toContain('Entity1');
+  });
+
+  test('getImmutableEntityNames handles explicitly non-immutable entities', () => {
+    const immutableEntityNames = schema.getImmutableEntityNames();
+    expect(immutableEntityNames).not.toContain('Entity3');
+  });
+});

packages/cli/src/schema.ts

@@ -69,4 +69,24 @@ export default class Schema {
       return isImmutable(entity);
     }).length;
   }
+
+  getImmutableEntityNames(): string[] {
+    return this.ast.definitions
+      .filter(
+        def =>
+          def.kind === 'ObjectTypeDefinition' &&
+          def.directives?.find(
+            directive =>
+              directive.name.value === 'entity' &&
+              directive.arguments?.find(arg => {
+                return (
+                  arg.name.value === 'immutable' &&
+                  arg.value.kind === 'BooleanValue' &&
+                  arg.value.value === true
+                );
+              }),
+          ) !== undefined,
+      )
+      .map(entity => (entity as graphql.ObjectTypeDefinitionNode).name.value);
+  }
 }

packages/ts/common/collections.ts

@@ -457,28 +457,6 @@ export class Entity extends TypedMap<string, Value> {
   }
 }
 
-/**
- * Common representation for entity triggers, this wraps the entity
- * and has fields for the operation type and the entity type.
- */
-export class EntityTrigger<T extends Entity> {
-  constructor(
-    public operation: EntityOp,
-    public type: string,
-    public data: T, // T is a specific type that extends Entity
-  ) {}
-}
-
-/**
- * Enum for entity operations.
- * Create, Modify, Remove
- */
-export enum EntityOp {
-  Create,
-  Modify,
-  Remove,
-}
-
 /**
  * The result of an operation, with a corresponding value and error type.
  */