feat: implements promise provider

Adds `PromiseProvider` storage class to save the user-provided promise library. Eliminates the use of `promiseLibrary` stores within class constructors. Creates `PromiseProvider.get()` hook to retrieve the latest promise-library state. Allows setter of promise-library on module export `mongodb.Promise`. Preserves `promiseLibrary` option for `MongoClient`. Adds "no-native-promise" eslint rule to prevent direct internal use of native promises.

NODE-2579

.eslintrc

@@ -8,7 +8,7 @@
   "parserOptions": {
     "ecmaVersion": 2018
   },
-  "plugins": ["prettier", "jsdoc"],
+  "plugins": ["prettier", "promise", "jsdoc"],
   "rules": {
     "prettier/prettier": "error",
 
@@ -30,8 +30,17 @@
 
     "no-console": "off",
     "eqeqeq": ["error", "always", { "null": "ignore" }],
-    "strict": ["error", "global"]
+    "strict": ["error", "global"],
+    "promise/no-native": "error"
   },
+  "overrides": [
+    {
+      "files": ["test/**/*.js"],
+      "rules": {
+        "promise/no-native": "off"
+      }
+    }
+  ],
   "settings": {
     "jsdoc": {
       "check-types": false,

index.js

@@ -1,12 +1,23 @@
 'use strict';
+
 const error = require('./lib/error');
 const Instrumentation = require('./lib/apm');
 const { BSON } = require('./lib/deps');
 const { Cursor, AggregationCursor, CommandCursor } = require('./lib/cursor');
+const PromiseProvider = require('./lib/promise_provider');
 
 // Set up the connect function
 const connect = require('./lib/mongo_client').connect;
 
+Object.defineProperty(connect, 'Promise', {
+  get: function() {
+    return PromiseProvider.get();
+  },
+  set: function(lib) {
+    PromiseProvider.set(lib);
+  }
+});
+
 // Expose error class
 connect.MongoError = error.MongoError;
 connect.MongoNetworkError = error.MongoNetworkError;

lib/admin.js

@@ -44,16 +44,14 @@ const executeOperation = require('./operations/execute_operation');
  * @returns {Admin} a collection instance.
  * @param {any} db
  * @param {any} topology
- * @param {any} promiseLibrary
  */
-function Admin(db, topology, promiseLibrary) {
+function Admin(db, topology) {
   if (!(this instanceof Admin)) return new Admin(db, topology);
 
   // Internal state
   this.s = {
     db: db,
-    topology: topology,
-    promiseLibrary: promiseLibrary
+    topology: topology
   };
 }
 

lib/bulk/common.js

@@ -1,5 +1,6 @@
 'use strict';
 
+const PromiseProvider = require('../promise_provider');
 const {
   BSON: { Long, ObjectId }
 } = require('../deps');
@@ -781,9 +782,6 @@ class BulkOperationBase {
     finalOptions = applyWriteConcern(finalOptions, { collection: collection }, options);
     const writeConcern = finalOptions.writeConcern;
 
-    // Get the promiseLibrary
-    const promiseLibrary = options.promiseLibrary || Promise;
-
     // Final results
     const bulkResult = {
       ok: 1,
@@ -832,8 +830,6 @@ class BulkOperationBase {
       executed: executed,
       // Collection
       collection: collection,
-      // Promise Library
-      promiseLibrary: promiseLibrary,
       // Fundamental error
       err: null,
       // check keys
@@ -1027,12 +1023,14 @@ class BulkOperationBase {
    * @param {any} callback
    */
   _handleEarlyError(err, callback) {
+    const Promise = PromiseProvider.get();
+
     if (typeof callback === 'function') {
       callback(err, null);
       return;
     }
 
-    return this.s.promiseLibrary.reject(err);
+    return Promise.reject(err);
   }
 
   /**

lib/change_stream.js

@@ -85,7 +85,6 @@ class ChangeStream extends EventEmitter {
       );
     }
 
-    this.promiseLibrary = parent.s.promiseLibrary;
     if (!this.options.readPreference && parent.s.readPreference) {
       this.options.readPreference = parent.s.readPreference;
     }
@@ -130,7 +129,7 @@ class ChangeStream extends EventEmitter {
    * @returns {Promise|void} returns Promise if no callback passed
    */
   hasNext(callback) {
-    return maybePromise(this.parent, callback, cb => this.cursor.hasNext(cb));
+    return maybePromise(callback, cb => this.cursor.hasNext(cb));
   }
 
   /**
@@ -142,7 +141,7 @@ class ChangeStream extends EventEmitter {
    * @returns {Promise|void} returns Promise if no callback passed
    */
   next(callback) {
-    return maybePromise(this.parent, callback, cb => {
+    return maybePromise(callback, cb => {
       if (this.isClosed()) {
         return cb(new MongoError('ChangeStream is closed'));
       }
@@ -170,7 +169,7 @@ class ChangeStream extends EventEmitter {
    * @returns {Promise} returns Promise if no callback passed
    */
   close(callback) {
-    return maybePromise(this.parent, callback, cb => {
+    return maybePromise(callback, cb => {
       if (this.closed) return cb();
 
       // flag the change stream as explicitly closed

lib/collection.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const { emitDeprecatedOptionWarning } = require('./utils');
+const PromiseProvider = require('./promise_provider');
 const ReadPreference = require('./read_preference');
 const { deprecate } = require('util');
 const {
@@ -111,6 +113,7 @@ const mergeKeys = ['ignoreUndefined'];
  */
 function Collection(db, topology, dbName, name, pkFactory, options) {
   checkCollectionName(name);
+  emitDeprecatedOptionWarning(options, ['promiseLibrary']);
 
   // Unpack variables
   const internalHint = null;
@@ -136,9 +139,6 @@ function Collection(db, topology, dbName, name, pkFactory, options) {
 
   const namespace = new MongoDBNamespace(dbName, name);
 
-  // Get the promiseLibrary
-  const promiseLibrary = options.promiseLibrary || Promise;
-
   // Set custom primary key factory if provided
   pkFactory = pkFactory == null ? ObjectId : pkFactory;
 
@@ -172,8 +172,6 @@ function Collection(db, topology, dbName, name, pkFactory, options) {
     internalHint: internalHint,
     // collectionHint
     collectionHint: collectionHint,
-    // Promise library
-    promiseLibrary: promiseLibrary,
     // Read Concern
     readConcern: ReadConcern.fromOptions(options),
     // Write Concern
@@ -453,9 +451,6 @@ Collection.prototype.find = deprecateOptions(
     // Add db object to the new options
     newOptions.db = this.s.db;
 
-    // Add the promise library
-    newOptions.promiseLibrary = this.s.promiseLibrary;
-
     // Set raw if available at collection level
     if (newOptions.raw == null && typeof this.s.raw === 'boolean') newOptions.raw = this.s.raw;
     // Set promoteLongs if available at collection level
@@ -757,11 +752,12 @@ Collection.prototype.insert = deprecate(function(docs, options, callback) {
 Collection.prototype.updateOne = function(filter, update, options, callback) {
   if (typeof options === 'function') (callback = options), (options = {});
   options = options || {};
+  const Promise = PromiseProvider.get();
 
   const err = checkForAtomicOperators(update);
   if (err) {
     if (typeof callback === 'function') return callback(err);
-    return this.s.promiseLibrary.reject(err);
+    return Promise.reject(err);
   }
 
   options = Object.assign({}, options);
@@ -836,13 +832,14 @@ Collection.prototype.replaceOne = function(filter, doc, options, callback) {
  * @returns {Promise<Collection~updateWriteOpResult>} returns Promise if no callback passed
  */
 Collection.prototype.updateMany = function(filter, update, options, callback) {
+  const Promise = PromiseProvider.get();
   if (typeof options === 'function') (callback = options), (options = {});
   options = options || {};
 
   const err = checkForAtomicOperators(update);
   if (err) {
     if (typeof callback === 'function') return callback(err);
-    return this.s.promiseLibrary.reject(err);
+    return Promise.reject(err);
   }
 
   options = Object.assign({}, options);
@@ -1786,6 +1783,8 @@ Collection.prototype.findOneAndReplace = function(filter, replacement, options,
  * @returns {Promise<Collection~findAndModifyWriteOpResultObject>} returns Promise if no callback passed
  */
 Collection.prototype.findOneAndUpdate = function(filter, update, options, callback) {
+  const Promise = PromiseProvider.get();
+
   if (typeof options === 'function') (callback = options), (options = {});
   options = options || {};
 
@@ -1798,7 +1797,7 @@ Collection.prototype.findOneAndUpdate = function(filter, update, options, callba
   const err = checkForAtomicOperators(update);
   if (err) {
     if (typeof callback === 'function') return callback(err);
-    return this.s.promiseLibrary.reject(err);
+    return Promise.reject(err);
   }
 
   const findOneAndUpdateOperation = new FindOneAndUpdateOperation(this, filter, update, options);
@@ -2018,9 +2017,6 @@ Collection.prototype.parallelCollectionScan = deprecate(function(options, callba
   // Ensure we have the right read preference inheritance
   options.readPreference = resolveReadPreference(this, options);
 
-  // Add a promiseLibrary
-  options.promiseLibrary = this.s.promiseLibrary;
-
   if (options.session) {
     options.session = undefined;
   }
@@ -2174,7 +2170,6 @@ Collection.prototype.initializeUnorderedBulkOp = function(options) {
     options.ignoreUndefined = this.s.options.ignoreUndefined;
   }
 
-  options.promiseLibrary = this.s.promiseLibrary;
   return unordered(this.s.topology, this, options);
 };
 
@@ -2196,7 +2191,7 @@ Collection.prototype.initializeOrderedBulkOp = function(options) {
   if (options.ignoreUndefined == null) {
     options.ignoreUndefined = this.s.options.ignoreUndefined;
   }
-  options.promiseLibrary = this.s.promiseLibrary;
+
   return ordered(this.s.topology, this, options);
 };
 

lib/cursor/cursor.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const { emitDeprecatedOptionWarning } = require('../utils');
+const PromiseProvider = require('../promise_provider');
 const ReadPreference = require('../read_preference');
 const { Transform, PassThrough } = require('stream');
 const { deprecate } = require('util');
@@ -101,14 +103,13 @@ class Cursor extends CoreCursor {
       options = this.operation.options;
     }
 
+    emitDeprecatedOptionWarning(options, ['promiseLibrary']);
+
     // Tailable cursor options
     const numberOfRetries = options.numberOfRetries || 5;
     const tailableRetryInterval = options.tailableRetryInterval || 500;
     const currentNumberOfRetries = numberOfRetries;
 
-    // Get the promiseLibrary
-    const promiseLibrary = options.promiseLibrary || Promise;
-
     // Internal cursor state
     this.s = {
       // Tailable cursor options
@@ -117,8 +118,6 @@ class Cursor extends CoreCursor {
       currentNumberOfRetries: currentNumberOfRetries,
       // State
       state: CursorState.INIT,
-      // Promise library
-      promiseLibrary,
       // explicitlyIgnoreSession
       explicitlyIgnoreSession: !!options.explicitlyIgnoreSession
     };
@@ -193,7 +192,7 @@ class Cursor extends CoreCursor {
       throw MongoError.create({ message: 'Cursor is closed', driver: true });
     }
 
-    return maybePromise(this, callback, cb => {
+    return maybePromise(callback, cb => {
       const cursor = this;
       if (cursor.isNotified()) {
         return cb(null, false);
@@ -221,7 +220,7 @@ class Cursor extends CoreCursor {
    * @returns {Promise} returns Promise if no callback passed
    */
   next(callback) {
-    return maybePromise(this, callback, cb => {
+    return maybePromise(callback, cb => {
       const cursor = this;
       if (cursor.s.state === CursorState.CLOSED || (cursor.isDead && cursor.isDead())) {
         cb(MongoError.create({ message: 'Cursor is closed', driver: true }));
@@ -746,6 +745,7 @@ class Cursor extends CoreCursor {
    * @returns {Promise} if no callback supplied
    */
   forEach(iterator, callback) {
+    const Promise = PromiseProvider.get();
     // Rewind cursor state
     this.rewind();
 
@@ -770,7 +770,7 @@ class Cursor extends CoreCursor {
         }
       });
     } else {
-      return new this.s.promiseLibrary((fulfill, reject) => {
+      return new Promise((fulfill, reject) => {
         each(this, (err, doc) => {
           if (err) {
             reject(err);
@@ -840,7 +840,7 @@ class Cursor extends CoreCursor {
         driver: true
       });
     }
-    return maybePromise(this, callback, cb => {
+    return maybePromise(callback, cb => {
       const cursor = this;
       const items = [];
 
@@ -934,6 +934,8 @@ class Cursor extends CoreCursor {
    * @returns {Promise} returns Promise if no callback passed
    */
   close(options, callback) {
+    const Promise = PromiseProvider.get();
+
     if (typeof options === 'function') (callback = options), (options = {});
     options = Object.assign({}, { skipKillCursors: false }, options);
 
@@ -953,7 +955,7 @@ class Cursor extends CoreCursor {
       }
 
       // Return a Promise
-      return new this.s.promiseLibrary(resolve => {
+      return new Promise(resolve => {
         resolve();
       });
     };
@@ -963,7 +965,7 @@ class Cursor extends CoreCursor {
         return this._endSession(() => completeClose());
       }
 
-      return new this.s.promiseLibrary(resolve => {
+      return new Promise(resolve => {
         this._endSession(() => completeClose().then(resolve));
       });
     }
@@ -1069,7 +1071,7 @@ class Cursor extends CoreCursor {
     if (this.cmd.readConcern) {
       delete this.cmd['readConcern'];
     }
-    return maybePromise(this, callback, cb => {
+    return maybePromise(callback, cb => {
       CoreCursor.prototype._next.apply(this, [cb]);
     });
   }