filehandle.read(buffer) can't read file when options are omitted

Version

v18.12.1

Platform

Linux ubuntu-focal 5.4.0-144-generic #161-Ubuntu SMP Fri Feb 3 14:49:04 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

No response

What steps will reproduce the bug?

const fs = require("fs/promises");

async function test() {
  let path = '/path/to/file';

  let buf = Buffer.alloc(4);
  let handle;
  try {
    handle = await fs.open(path);
    {
      let buf = Buffer.alloc(4);
      let { bytesRead, buffer } = await handle.read(buf);
      //let { bytesRead, buffer } = await handle.read(buf, {}); // It is behavior I would expect.
      console.log(bytesRead);
      console.log(buffer);
      console.log(buf);
    }
  } finally {
    await handle?.close();
  }
}
test();

How often does it reproduce? Is there a required condition?

always

What is the expected behavior? Why is that the expected behavior?

https://nodejs.org/dist/latest-v18.x/docs/api/fs.html#filehandlereadbuffer-options

Even if you omit options, it will be default values.

What do you see instead?

0
<Buffer 00 00 00 00>
<Buffer 00 00 00 00>

Additional information

No response

node/lib/internal/fs/promises.js

Lines 569 to 571 in a94966f

    
           if (offset == null) { 
        
             offset = 0; 
        
           } else {

It looks like the length is still zero here.
Adding the following might work as expected.

length = buffer.byteLength - offset

is this issue valid? please confirm.

fs: make offset, position & length args in fh.read() optional

@pulkit-30

Edit: Oh, I see #51087 probably fixes this. Sorry for the noise!

@pulkit-30 I can still reproduce this on node 21.5.0 and 20.10.0 with this script:

import { open } from 'fs/promises';

async function main() {
  const bytes = new Uint8Array(8);
  const fileHandle = await open(process.argv[2]);
  console.debug(await fileHandle.read(bytes));
}

main();

Invoked like this:

node index.mjs some-file.txt

Produces this output:

[Object: null prototype] {
  bytesRead: 0,
  buffer: Uint8Array(8) [
    0, 0, 0, 0,
    0, 0, 0, 0
  ]
}

fs: make offset, position & length args in fh.read() optional

Navigation Menu

Repository navigation

filehandle.read(buffer) can't read file when options are omitted #47183

Version

Platform

Subsystem

What steps will reproduce the bug?

How often does it reproduce? Is there a required condition?

What is the expected behavior? Why is that the expected behavior?

What do you see instead?

Additional information

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

filehandle.read(buffer) can't read file when options are omitted #47183

Description

Version

Platform

Subsystem

What steps will reproduce the bug?

How often does it reproduce? Is there a required condition?

What is the expected behavior? Why is that the expected behavior?

What do you see instead?

Additional information

Activity

H1Gdev commented on Mar 21, 2023

pulkit-30 commented on Dec 7, 2023

markrian commented on Jan 2, 2024

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions