setUint8 throws when ArrayBuffer is resizable

[guest271314]

This should work

import * as std from "qjs:std";
import * as os from "qjs:os";

const buffer = new ArrayBuffer(0, {maxByteLength: 16384});
const view = new DataView(buffer);
const arr = [97, 98, 99];
const file = os.open("test.txt", os.O_RDWR | os.O_CREAT | os.O_TRUNC, 0o764);
buffer.resize(arr.length);
console.log(buffer.byteLength);
for (let i = 0; i < arr.length; i++) {
  console.log(`setUint8(${i}, ${arr[i]})`);
  view.setUint8(i, arr[i]);
}
console.log(os.write(file, buffer, 0, buffer.byteLength));
console.log(os.close(file));

I get

3
setUint8(0, 97)
Possibly unhandled promise rejection: RangeError: out of bound
    at setUint8 (native)
    at <anonymous> (test.js:15:17)

Looks like a bug in DataView reading resizable ArrayBuffer.

This works as expected

import * as std from "qjs:std";
import * as os from "qjs:os";

const buffer = new ArrayBuffer(3);
const view = new DataView(buffer);
const arr = [97, 98, 99];
const file = os.open("test.txt", os.O_RDWR | os.O_CREAT | os.O_TRUNC, 0o764);
//buffer.resize(arr.length);
console.log(buffer.byteLength);
for (let i = 0; i < arr.length; i++) {
  console.log(`setUint8(${i}, ${arr[i]})`);
  view.setUint8(i, arr[i]);
}
console.log(os.write(file, buffer, 0, buffer.byteLength));
console.log(os.close(file));

3
setUint8(0, 97)
setUint8(1, 98)
setUint8(2, 99)
3
0

ls -l test.txt
-rwxr--r-- 1 user user 3 Mar 20 05:09 test.txt

[saghul]

I think the problem lies here: https://github.com/quickjs-ng/quickjs/blob/97e6ef94c5aa1d9975d5c4bd78571ece77c8ec0d/quickjs.c#L52312

The DataView length is not updated when the backing buffer is updated.

[guest271314]

Kind of related, I encounted this because I was using std.open() which does not provide an option to set file permissions, then tried using os.open() which does set file permissions. Setting file permission to executable, or otherwise, without necessarily writing to the file handle would be useful. Then I could just keep using std.open() and then do something like os.chmod(filename, 0o764).

[guest271314]

Verified working as expected with the test case in OP

qjs test.js
3
setUint8(0, 97)
setUint8(1, 98)
setUint8(2, 99)
3
0