Fix relation field unknown target object (#13129)

Fixes https://github.com/twentyhq/twenty/issues/12867

Issue:
when you have a variable `toto` which is: `Record<string, MyType>` and
you do toto['xxx'], this will be typed as `MyType` instead of `MyType |
undefined`

Solutions:
- activate `noUncheckedIndexedAccess` check in tsconfig, this is the
preferred solution but will take time to get there (this raises 600+
errors)
- use a Map: cf https://github.com/twentyhq/twenty/pull/13125/files
- set the type to Partial<Record<string, MyType>>. Drawback is that when
you do Object.values(toto), you'll get `Array<MyType | undefined>`.
Hence why we have to filter these behind


<img width="1512" alt="image"
src="https://github.com/user-attachments/assets/d0a0bfed-c441-4e53-84c2-2da98ccbcf50"
/>

packages/twenty-server/src/engine/api/graphql/workspace-query-runner/factories/query-result-getters/query-result-getters.factory.ts

@@ -19,9 +19,9 @@ import { PersonQueryResultGetterHandler } from 'src/engine/api/graphql/workspace
 import { WorkspaceMemberQueryResultGetterHandler } from 'src/engine/api/graphql/workspace-query-runner/factories/query-result-getters/handlers/workspace-member-query-result-getter.handler';
 import { CompositeInputTypeDefinitionFactory } from 'src/engine/api/graphql/workspace-schema-builder/factories/composite-input-type-definition.factory';
 import { FileService } from 'src/engine/core-modules/file/services/file.service';
+import { ObjectMetadataItemWithFieldMaps } from 'src/engine/metadata-modules/types/object-metadata-item-with-field-maps';
 import { ObjectMetadataMaps } from 'src/engine/metadata-modules/types/object-metadata-maps';
 import { isFieldMetadataInterfaceOfType } from 'src/engine/utils/is-field-metadata-of-type.util';
-import { ObjectMetadataItemWithFieldMaps } from 'src/engine/metadata-modules/types/object-metadata-item-with-field-maps';
 
 // TODO: find a way to prevent conflict between handlers executing logic on object relations
 // And this factory that is also executing logic on object relations
@@ -121,6 +121,10 @@ export class QueryResultGettersFactory {
   ): Promise<ObjectRecord> {
     const objectMetadataMapItem = objectMetadataMaps.byId[objectMetadataItemId];
 
+    if (!isDefined(objectMetadataMapItem)) {
+      throw new Error('Object metadata map item is not defined');
+    }
+
     const handler = this.getHandler(objectMetadataMapItem.nameSingular);
 
     const relationFields = Object.keys(record)

packages/twenty-server/src/engine/api/graphql/workspace-resolver-builder/workspace-resolver.factory.ts

@@ -1,6 +1,7 @@
 import { Injectable, Logger } from '@nestjs/common';
 
 import { IResolvers } from '@graphql-tools/utils';
+import { isDefined } from 'twenty-shared/utils';
 
 import { DeleteManyResolverFactory } from 'src/engine/api/graphql/workspace-resolver-builder/factories/delete-many-resolver.factory';
 import { DestroyManyResolverFactory } from 'src/engine/api/graphql/workspace-resolver-builder/factories/destroy-many-resolver.factory';
@@ -75,7 +76,9 @@ export class WorkspaceResolverFactory {
       Mutation: {},
     };
 
-    for (const objectMetadata of Object.values(objectMetadataMaps.byId)) {
+    for (const objectMetadata of Object.values(objectMetadataMaps.byId).filter(
+      isDefined,
+    )) {
       // Generate query resolvers
       for (const methodName of workspaceResolverBuilderMethods.queries) {
         const resolverName = getResolverName(objectMetadata, methodName);

packages/twenty-server/src/engine/api/graphql/workspace-schema.factory.ts

@@ -3,6 +3,7 @@ import { Injectable } from '@nestjs/common';
 import { makeExecutableSchema } from '@graphql-tools/schema';
 import { GraphQLSchema, printSchema } from 'graphql';
 import { gql } from 'graphql-tag';
+import { isDefined } from 'twenty-shared/utils';
 
 import { ScalarsExplorerService } from 'src/engine/api/graphql/services/scalars-explorer.service';
 import { workspaceResolverBuilderMethodNames } from 'src/engine/api/graphql/workspace-resolver-builder/factories/factories';
@@ -56,13 +57,13 @@ export class WorkspaceSchemaFactory {
       );
     }
 
-    const objectMetadataCollection = Object.values(objectMetadataMaps.byId).map(
-      (objectMetadataItem) => ({
+    const objectMetadataCollection = Object.values(objectMetadataMaps.byId)
+      .filter(isDefined)
+      .map((objectMetadataItem) => ({
         ...objectMetadataItem,
         fields: Object.values(objectMetadataItem.fieldsById),
         indexes: objectMetadataItem.indexMetadatas,
-      }),
-    );
+      }));
 
     // Get typeDefs from cache
     let typeDefs = await this.workspaceCacheStorageService.getGraphQLTypeDefs(

packages/twenty-server/src/engine/api/rest/core/interfaces/rest-api-base.handler.ts

@@ -171,6 +171,12 @@ export abstract class RestApiBaseHandler {
               objectMetadata.objectMetadataMaps.byId[
                 field.relationTargetObjectMetadataId
               ];
+
+            if (!isDefined(relationTargetObjectMetadata)) {
+              throw new BadRequestException(
+                `Object metadata relation target not found for relation creation payload`,
+              );
+            }
             const depth2Relations = this.getRelations({
               objectMetadata: {
                 objectMetadataMaps: objectMetadata.objectMetadataMaps,

packages/twenty-server/src/engine/api/rest/core/query-builder/utils/map-field-metadata-to-graphql-query.utils.ts

@@ -1,4 +1,5 @@
 import { FieldMetadataType } from 'twenty-shared/types';
+import { isDefined } from 'twenty-shared/utils';
 
 import { FieldMetadataInterface } from 'src/engine/metadata-modules/field-metadata/interfaces/field-metadata.interface';
 import { RelationType } from 'src/engine/metadata-modules/field-metadata/interfaces/relation-type.interface';
@@ -58,6 +59,10 @@ export const mapFieldMetadataToGraphqlQuery = (
     const relationMetadataItem =
       objectMetadataMaps.byId[targetObjectMetadataId];
 
+    if (!isDefined(relationMetadataItem)) {
+      return '';
+    }
+
     return `${field.name}
     {
       id