feat: warn about non-existing relationships

Author: gajus

src/utilities/generateDataLoaderFactory.js

@@ -10,13 +10,18 @@ import type {
   DataTypeMapType,
   IndexType
 } from '../types';
+import Logger from '../Logger';
 import generateFlowTypeDocument from './generateFlowTypeDocument';
 import indent from './indent';
 import isJoiningTable from './isJoiningTable';
 import createColumnSelector from './createColumnSelector';
 import createLoaderTypePropertyDeclaration from './createLoaderTypePropertyDeclaration';
 import pluralizeTableName from './pluralizeTableName';
 
+const log = Logger.child({
+  namespace: 'generateDataLoaderFactory'
+});
+
 const createLoaderByIdsDeclaration = (loaderName: string, tableName: string, keyColumnName, columnSelector: string, resultIsArray: boolean) => {
   return `const ${loaderName} = new DataLoader((ids) => {
   return getByIds(connection, '${tableName}', ids, '${keyColumnName}', '${columnSelector}', ${String(resultIsArray)}, NotFoundError);
@@ -177,6 +182,14 @@ export default (
         return column.mappedTableName === relation.resource;
       });
 
+      if (!resourceTableColumns.length) {
+        log.warn({
+          relation
+        }, 'resource without columns');
+
+        continue;
+      }
+
       const realResourceTableName = resourceTableColumns[0].tableName;
 
       const tableColumnSelector = createColumnSelector(resourceTableColumns, 'r2');