Bun.stdin/Bun.stdout results in Unseekable for read/write

[fnky]

Version

0.1.3

Platform

Darwin fnky 18.7.0 Darwin Kernel Version 18.7.0: Tue Aug 20 16:57:14 PDT 2019; root:xnu-4903.271.2~2/RELEASE_X86_64 x86_64

What steps will reproduce the bug?

Failing to write to stdout:

await Bun.write(Bun.stdout, "output");

Failing to read from stdin:

console.log(await Bun.stdin.text());

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

Can be reproduced at least on both my MacBooks using macOS Mojave 10.14.6. Someone did confirm it worked for them using Ubuntu.

What is the expected behavior?

To write "output" to stdout for the first example.

To await for stdin and console.log the awaited string input.

What do you see instead?

The stdout example outputs

Unseekable
syscall: "write"

While the stdin example outputs

Unseekable
syscall: "read"

Additional information

No response

[fnky]

I tried using the node API to write to stdout and got some more output from the error in the callback:

import fs from "node:fs";
fs.write(1, "output", 0, "utf8", (err, written) => {
  console.log(err, written);
});

produced the following output:

106 |   queueMicrotask(function () {
107 |     try {
108 |       args[args.length - 1](
109 |         null,
110 |
111 |         fsFunction.apply(fs, args.slice(0, args.length - 1))
           ^
 ENXIO: Device not configured
syscall: "pwrite"
  errno: -6

      at node:fs:111:8
 undefined

as well as for reading from stdin:

import fs from "node:fs";
import { Buffer } from "node:buffer";

const buf = Buffer.alloc(16);
fs.read(0, buf, 0, 16, 0, (err, bytesRead) => {
  console.log(err, bytesRead);
});

produces

106 |   queueMicrotask(function () {
107 |     try {
108 |       args[args.length - 1](
109 |         null,
110 |
111 |         fsFunction.apply(fs, args.slice(0, args.length - 1))
           ^
 ENXIO: Device not configured
syscall: "pread"
  errno: -6

      at node:fs:111:8
 undefined

The line error report at queueMicrotask is a red flag, since using writeSync/readSync will place it at the correct call in the code.

[fnky]

Writing directly to /dev/stdout//dev/tty/stdout file descriptor with node FS works:

fs.writeFileSync("/dev/stdout", "output", "utf-8"); // => output
fs.writeFileSync(1, "output", "utf-8"); // => output

but using Bun.file fails with the same error:

await Bun.write(Bun.file("/dev/stdout"), "output");

[Jarred-Sumner]

This is a macOS bug. It shouldn't be using pwrite. It should use write

[TzviPM]

@Jarred-Sumner do you mean that AsyncIO#write should be using write instead of pwrite (https://github.com/oven-sh/bun/blob/main/src/io/io_darwin.zig#L1427)? Or that Bun.write should use write instead of pwrite when destination_blob points to stdout or stderr (https://github.com/oven-sh/bun/blob/main/src/io/io_darwin.zig#L1427)? Or something else?

[tbjgolden]

I'm also getting this; I'm on the MacOS Ventura beta fwiw

[tbjgolden]

I'm guessing a fix to this dependends on https://github.com/oven-sh/bun/pull/1115

as the fix might involve checking which os and they might wanna reuse the code from it

[Jarred-Sumner]

I had a fix for this actually and then lost the code after a git reset HEAD —hard

Will fix it this week

On Sun, Aug 21, 2022 at 8:18 AM Tom Golden @.***> wrote:

I'm guessing a fix to this dependends on #1115 https://github.com/oven-sh/bun/pull/1115

as the fix might involve checking which os and they might wanna reuse the code from it

— Reply to this email directly, view it on GitHub https://github.com/oven-sh/bun/issues/646#issuecomment-1221565648, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAFNGS4KDDL4IXMDAUFXHJLV2JCCTANCNFSM53METVMQ . You are receiving this because you were mentioned.Message ID: @.***>

[franciscop]

Thanks @Jarred-Sumner! Waiting on this to continue with https://github.com/oven-sh/bun/issues/894, I believe I'm pretty close to polyfill process.stdin/stdout :)

[ctjlewis]

Thanks @Jarred-Sumner - need access to a stream to replicate ora-like spinner, chalk equivalent currently available at bun-style.

[guest271314]

I don't think reading from/writing stdin/stdout works on *nix for several cases. Tests will provide empirical evidence.

[Jarred-Sumner]

This was fixed long ago

[davidchambers]

@Jarred-Sumner, I'm still having trouble with Bun.stdin on macOS:

$ bun --revision
1.0.15+b3bdf22eb

$ uname -mprs
Darwin 21.6.0 arm64 arm

$ cat stdin.js
console.log(JSON.stringify(await Bun.stdin.text()));

$ echo hello | bun run stdin.js
""

[Jarred-Sumner]

@davidchambers

Please run bun upgrade --canary and try again

[davidchambers]

Works now! :tada: