stream: readable read one buffer at a time #60441

ronag · 2025-10-27T18:44:50Z

Instead of wasting cycles concatenating buffers, just return each
one by one.

Similar (but not exact) old behavior can be achieved by using
`readable.read(readable.readableLength)` instead of
`readable.read()`. In some edge cases it might be necessary
to do a `readable.read(0)` first.

nodejs-github-bot · 2025-10-27T18:44:55Z

Review requested:

@nodejs/streams

test/parallel/test-stream-readable-infinite-read.js

mcollina

code lgtm

I think some docs changes are needed

mcollina · 2026-01-02T08:05:20Z

Marked as semver-major.

lpinca · 2026-01-02T08:27:37Z

I'm -1 on this unless there is a strong reason for it. Historically, readable.read() has always returned all queued data. If this lands, I think that the easiest workaround for modules affected by the breaking change would be replacing readable.read() with readable.read(readable.readableLength).

ronag · 2026-01-02T08:48:08Z

I'm -1 on this unless there is a strong reason for it.

The performance overhead is huge. As it stand we should at least add a note to avoid this api for anything performance sensitive.

If this lands, I think that the easiest workaround for modules affected by the breaking change would be replacing readable.read() with readable.read(readable.readableLength).

Good point.

ronag · 2026-01-02T08:51:56Z

I think some docs changes are needed

What doc changes are you roughly asking for?

Instead of wasting cycles concatenating buffers, just return each one by one. Old behavior can be achieved by using `readable.read(readable.readableLength)` instead of `readable.read()`. PR: nodejs#60441

github-actions · 2026-01-02T08:58:57Z

Failed to start CI

   ⚠  Commits were pushed since the last approving review:
   ⚠  - stream: readable read one buffer at a time
   ✘  Refusing to run CI on potentially unsafe PR

https://github.com/nodejs/node/actions/runs/20654449594

github-actions · 2026-01-03T22:27:17Z

Failed to start CI

   ⚠  Commits were pushed since the last approving review:
   ⚠  - stream: readable read one buffer at a time
   ⚠  - Update test/parallel/test-stream-readable-readable-one.js
   ⚠  - fixup
   ✘  Refusing to run CI on potentially unsafe PR

https://github.com/nodejs/node/actions/runs/20683777042

github-actions · 2026-01-03T22:39:34Z

Failed to start CI

   ⚠  Commits were pushed since the last approving review:
   ⚠  - stream: readable read one buffer at a time
   ⚠  - Update test/parallel/test-stream-readable-readable-one.js
   ⚠  - fixup
   ✘  Refusing to run CI on potentially unsafe PR

https://github.com/nodejs/node/actions/runs/20683908897

mcollina

lgtm

nodejs-github-bot · 2026-01-04T16:24:13Z

CI: https://ci.nodejs.org/job/node-test-pull-request/70668/

nodejs-github-bot · 2026-01-04T17:11:35Z

CI: https://ci.nodejs.org/job/node-test-pull-request/70669/

mcollina

lgtm

nodejs-github-bot · 2026-01-05T08:51:29Z

CI: https://ci.nodejs.org/job/node-test-pull-request/70672/

Instead of wasting cycles concatenating buffers, just return each one by one. Similar (but not exact) old behavior can be achieved by using `readable.read(readable.readableLength)` instead of `readable.read()`. In some edge cases it might be necessary to do a `readable.read(0)` first. PR: nodejs#60441

ronag · 2026-01-05T09:27:53Z

@lpinca Do you need help fixing ws in relation to this PR or can you deal with it yourself?

mcollina

lgtm

nodejs-github-bot · 2026-01-05T09:53:06Z

CI: https://ci.nodejs.org/job/node-test-pull-request/70676/

lpinca · 2026-01-05T09:53:46Z

@lpinca Do you need help fixing ws in relation to this PR or can you deal with it yourself?

I've already fixed it in websockets/ws@1998485

ronag · 2026-01-05T09:54:54Z

CITGM: https://ci.nodejs.org/view/Node.js-citgm/job/citgm-smoker/3663/

ronag requested a review from mcollina October 27, 2025 18:44

nodejs-github-bot added needs-ci PRs that need a full CI run. stream Issues and PRs related to the stream subsystem. labels Oct 27, 2025

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stream: readable read one buffer at a time #60441

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