From 0793398b4f203994cf039fa84bd9e2514796d8a6 Mon Sep 17 00:00:00 2001 From: David Mark Clements Date: Fri, 5 Jul 2019 20:02:08 +0200 Subject: stream: add null push transform in async_iterator when the readable side of a transform ends any for await loop on that transform stream should also complete. This fix prevents for await loop on a transform stream from hanging indefinitely. PR-URL: https://github.com/nodejs/node/pull/28566 Reviewed-By: Anna Henningsen Reviewed-By: Jeremiah Senkpiel Reviewed-By: Ruben Bridgewater Reviewed-By: James M Snell Reviewed-By: Rich Trott --- lib/internal/streams/async_iterator.js | 2 +- .../test-stream-readable-async-iterators.js | 26 +++++++++++++++++++++- 2 files changed, 26 insertions(+), 2 deletions(-) diff --git a/lib/internal/streams/async_iterator.js b/lib/internal/streams/async_iterator.js index defba235ad..89a1dae7fd 100644 --- a/lib/internal/streams/async_iterator.js +++ b/lib/internal/streams/async_iterator.js @@ -155,7 +155,7 @@ const createReadableStreamAsyncIterator = (stream) => { }); iterator[kLastPromise] = null; - finished(stream, (err) => { + finished(stream, { writable: false }, (err) => { if (err && err.code !== 'ERR_STREAM_PREMATURE_CLOSE') { const reject = iterator[kLastReject]; // Reject if we are waiting for data in the Promise returned by next() and diff --git a/test/parallel/test-stream-readable-async-iterators.js b/test/parallel/test-stream-readable-async-iterators.js index b50a6b1734..12971cb236 100644 --- a/test/parallel/test-stream-readable-async-iterators.js +++ b/test/parallel/test-stream-readable-async-iterators.js @@ -1,7 +1,7 @@ 'use strict'; const common = require('../common'); -const { Readable, PassThrough, pipeline } = require('stream'); +const { Readable, Transform, PassThrough, pipeline } = require('stream'); const assert = require('assert'); async function tests() { @@ -396,6 +396,30 @@ async function tests() { } } + { + console.log('readable side of a transform stream pushes null'); + const transform = new Transform({ + objectMode: true, + transform: (chunk, enc, cb) => { cb(null, chunk); } + }); + transform.push(0); + transform.push(1); + process.nextTick(() => { + transform.push(null); + }); + + const mustReach = [ common.mustCall(), common.mustCall() ]; + + const iter = transform[Symbol.asyncIterator](); + assert.strictEqual((await iter.next()).value, 0); + + for await (const d of iter) { + assert.strictEqual(d, 1); + mustReach[0](); + } + mustReach[1](); + } + { console.log('all next promises must be resolved on end'); const r = new Readable({ -- cgit v1.2.3