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

[H1Gdev]

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

[H1Gdev]

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

[pulkit-30]

is this issue valid? please confirm.

[markrian]

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
 ]
}