feat!: remove support for a custom Promise implementation

packages/pg-cursor/index.js

@@ -18,7 +18,6 @@ class Cursor extends EventEmitter {
     this._queue = []
     this.state = 'initialized'
     this._result = new Result(this._conf.rowMode, this._conf.types)
-    this._Promise = this._conf.Promise || global.Promise
     this._cb = null
     this._rows = null
     this._portal = null
@@ -212,7 +211,7 @@ class Cursor extends EventEmitter {
     let promise
 
     if (!cb) {
-      promise = new this._Promise((resolve, reject) => {
+      promise = new Promise((resolve, reject) => {
         cb = (err) => (err ? reject(err) : resolve())
       })
     }
@@ -235,7 +234,7 @@ class Cursor extends EventEmitter {
     let promise
 
     if (!cb) {
-      promise = new this._Promise((resolve, reject) => {
+      promise = new Promise((resolve, reject) => {
         cb = (err, rows) => (err ? reject(err) : resolve(rows))
       })
     }

packages/pg-pool/index.js

@@ -27,7 +27,7 @@ function throwOnDoubleRelease() {
   throw new Error('Release called on client which has already been released to the pool.')
 }
 
-function promisify(Promise, callback) {
+function promisify(callback) {
   if (callback) {
     return { callback: callback, result: undefined }
   }
@@ -93,7 +93,6 @@ class Pool extends EventEmitter {
     this.options.maxLifetimeSeconds = this.options.maxLifetimeSeconds || 0
     this.log = this.options.log || function () {}
     this.Client = this.options.Client || Client || require('pg').Client
-    this.Promise = this.options.Promise || global.Promise
 
     if (typeof this.options.idleTimeoutMillis === 'undefined') {
       this.options.idleTimeoutMillis = 10000
@@ -109,7 +108,6 @@ class Pool extends EventEmitter {
   }
 
   _promiseTry(f) {
-    const Promise = this.Promise
     if (typeof Promise.try === 'function') {
       return Promise.try(f)
     }
@@ -190,10 +188,10 @@ class Pool extends EventEmitter {
   connect(cb) {
     if (this.ending) {
       const err = new Error('Cannot use a pool after calling end on the pool')
-      return cb ? cb(err) : this.Promise.reject(err)
+      return cb ? cb(err) : Promise.reject(err)
     }
 
-    const response = promisify(this.Promise, cb)
+    const response = promisify(cb)
     const result = response.result
 
     // if we don't have to connect a new client, don't do so
@@ -431,7 +429,7 @@ class Pool extends EventEmitter {
   query(text, values, cb) {
     // guard clause against passing a function as the first parameter
     if (typeof text === 'function') {
-      const response = promisify(this.Promise, text)
+      const response = promisify(text)
       setImmediate(function () {
         return response.callback(new Error('Passing a function as the first parameter to pool.query is not supported'))
       })
@@ -443,7 +441,7 @@ class Pool extends EventEmitter {
       cb = values
       values = undefined
     }
-    const response = promisify(this.Promise, cb)
+    const response = promisify(cb)
     cb = response.callback
 
     this.connect((err, client) => {
@@ -489,10 +487,10 @@ class Pool extends EventEmitter {
     this.log('ending')
     if (this.ending) {
       const err = new Error('Called end on pool more than once')
-      return cb ? cb(err) : this.Promise.reject(err)
+      return cb ? cb(err) : Promise.reject(err)
     }
     this.ending = true
-    const promised = promisify(this.Promise, cb)
+    const promised = promisify(cb)
     this._endCallback = promised.callback
     this._pulseQueue()
     return promised.result

packages/pg/lib/client.js

@@ -20,11 +20,6 @@ const queryQueueDeprecationNotice = nodeUtils.deprecate(
   'Client.queryQueue is deprecated and will be removed in pg@9.0.'
 )
 
-const byoPromiseDeprecationNotice = nodeUtils.deprecate(
-  () => {},
-  'Passing a custom Promise implementation to the Client/Pool constructor is deprecated and will be removed in pg@9.0.'
-)
-
 const queryQueueLengthDeprecationNotice = nodeUtils.deprecate(
   () => {},
   'Calling client.query() when the client is already executing a query is deprecated and will be removed in pg@9.0. Use async/await or an external async flow control mechanism instead.'
@@ -53,10 +48,6 @@ class Client extends EventEmitter {
 
     const c = config || {}
 
-    if (c.Promise) {
-      byoPromiseDeprecationNotice()
-    }
-    this._Promise = c.Promise || global.Promise
     this._types = new TypeOverrides(c.types)
     this._ending = false
     this._ended = false
@@ -205,7 +196,7 @@ class Client extends EventEmitter {
       return
     }
 
-    return new this._Promise((resolve, reject) => {
+    return new Promise((resolve, reject) => {
       this._connect((error) => {
         if (error) {
           reject(error)
@@ -247,8 +238,7 @@ class Client extends EventEmitter {
       return
     }
     const con = this.connection
-    this._Promise
-      .resolve()
+    Promise.resolve()
       .then(() => this.password(this.connectionParameters))
       .then((pass) => {
         if (pass !== undefined) {
@@ -604,7 +594,7 @@ class Client extends EventEmitter {
       readTimeout = config.query_timeout || this.connectionParameters.query_timeout
       query = new Query(config, values, callback)
       if (!query.callback) {
-        result = new this._Promise((resolve, reject) => {
+        result = new Promise((resolve, reject) => {
           query.callback = (err, res) => (err ? reject(err) : resolve(res))
         }).catch((err) => {
           // replace the stack trace that leads to `TCP.onStreamRead` with one that leads back to the
@@ -692,7 +682,7 @@ class Client extends EventEmitter {
       if (cb) {
         cb()
       } else {
-        return this._Promise.resolve()
+        return Promise.resolve()
       }
     }
 
@@ -707,7 +697,7 @@ class Client extends EventEmitter {
     if (cb) {
       this.connection.once('end', cb)
     } else {
-      return new this._Promise((resolve) => {
+      return new Promise((resolve) => {
         this.connection.once('end', resolve)
       })
     }

packages/pg/lib/native/client.js

@@ -24,7 +24,6 @@ const Client = (module.exports = function (config) {
   EventEmitter.call(this)
   config = config || {}
 
-  this._Promise = config.Promise || global.Promise
   this._types = new TypeOverrides(config.types)
 
   this.native = new Native({
@@ -134,7 +133,7 @@ Client.prototype.connect = function (callback) {
     return
   }
 
-  return new this._Promise((resolve, reject) => {
+  return new Promise((resolve, reject) => {
     this._connect((error) => {
       if (error) {
         reject(error)
@@ -176,7 +175,7 @@ Client.prototype.query = function (config, values, callback) {
     query = new NativeQuery(config, values, callback)
     if (!query.callback) {
       let resolveOut, rejectOut
-      result = new this._Promise((resolve, reject) => {
+      result = new Promise((resolve, reject) => {
         resolveOut = resolve
         rejectOut = reject
       }).catch((err) => {
@@ -254,7 +253,7 @@ Client.prototype.end = function (cb) {
   }
   let result
   if (!cb) {
-    result = new this._Promise(function (resolve, reject) {
+    result = new Promise(function (resolve, reject) {
       cb = (err) => (err ? reject(err) : resolve())
     })
   }

packages/pg/test/integration/client/query-as-promise-tests.js

@@ -1,5 +1,4 @@
 'use strict'
-const bluebird = require('bluebird')
 const helper = require('../test-helper')
 const pg = helper.pg
 const assert = require('assert')
@@ -33,15 +32,21 @@ suite.test('promise API', (cb) => {
   })
 })
 
-suite.test('promise API with configurable promise type', (cb) => {
-  const client = new pg.Client({ Promise: bluebird })
+// The `Promise` constructor option was removed in pg@9.0; a client always uses the global Promise
+// now, and passing one is ignored rather than honoured.
+suite.test('a supplied promise type is ignored', (cb) => {
+  class NotAPromise extends Promise {}
+
+  const client = new pg.Client({ Promise: NotAPromise })
   const connectPromise = client.connect()
-  assert(connectPromise instanceof bluebird, 'Client connect() returns configured promise')
+  assert(connectPromise instanceof Promise, 'Client connect() returns a promise')
+  assert(!(connectPromise instanceof NotAPromise), 'Client connect() ignores a supplied promise type')
 
   connectPromise
     .then(() => {
       const queryPromise = client.query('SELECT 1')
-      assert(queryPromise instanceof bluebird, 'Client query() returns configured promise')
+      assert(queryPromise instanceof Promise, 'Client query() returns a promise')
+      assert(!(queryPromise instanceof NotAPromise), 'Client query() ignores a supplied promise type')
 
       return queryPromise.then(() => {
         client.end(cb)