lib: Fix bug when migrating a table with no foreign keys to having some

Author: nwoltman

lib/TableDefinition.js

@@ -5,7 +5,6 @@ const Operation = require('./Operation');
 
 const cloneDeep = require('lodash/cloneDeep');
 const diffKeys = require('./utils/diffKeys');
-const isEmpty = require('lodash/isEmpty');
 const isEqual = require('lodash/isEqual');
 
 const KEY_TYPES = {
@@ -753,7 +752,7 @@ function generateForegnKeysSchema(createDefinitions) {
     };
   }
 
-  return isEmpty(foreignKeys) ? null : foreignKeys;
+  return foreignKeys;
 }
 
 function arraysEqual(a, b) {

test/integration/addForeignKeys.js

@@ -0,0 +1,51 @@
+'use strict';
+
+const MySQLPlus = require('../../lib/MySQLPlus');
+
+const config = require('../config');
+
+const ColTypes = MySQLPlus.ColTypes;
+
+describe('when migrating a table with no foreign keys to having some foreign keys', function() {
+
+  const pool = MySQLPlus.createPool(config);
+  const pool2 = MySQLPlus.createPool(config);
+
+  pool.defineTable('add_foreign_keys_foreign', {
+    columns: {
+      id: ColTypes.int().notNull().primaryKey(),
+    },
+  });
+  pool.defineTable('add_foreign_keys_main', {
+    columns: {
+      id: ColTypes.int().notNull().index(),
+    },
+  });
+  pool2.defineTable('add_foreign_keys_main', {
+    columns: {
+      id: ColTypes.int().notNull().index(),
+    },
+    foreignKeys: {
+      id: 'add_foreign_keys_foreign.id',
+    },
+  });
+
+  before(done => {
+    pool.sync(err => {
+      if (err) {
+        throw err;
+      }
+
+      pool.end(done);
+    });
+  });
+
+  after(done => {
+    pool2.end(done);
+  });
+
+  it('should not error', done => {
+    pool2.sync(done);
+  });
+
+});