uutils/coreutils

Various problems in different id handling in `id` command

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#10006 opened on Jan 3, 2026

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Description

Component

id

Description

Various problems in different id handling in id command

Test / Reproduction Steps

  1. id pretty print crash on malformed group id Issue: uutils id command crashes when given a malformed group id for pretty printing. Test:
sudo setpriv --regid 1337 --clear-groups target/release/id -p
login    root
uid    root

thread 'main' panicked at src/uu/id/src/id.rs:503:49:
called `Result::unwrap()` on an `Err` value: Custom { kind: NotFound, error: "No such id: 1337" }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
  1. inconsistency in uutil's id & C version Issue: uutils id command shows incorrect group information when the effective group ID is changed. Test: add two users first
useradd -u 2000 u2000 -M
useradd -u 3000 u3000 -M

then

sudo setpriv --reuid 3000 --egid 2000 --clear-groups target/release/id
uid=3000(u3000) gid=0(root) egid=2000(u2000) groups=0(root)
sudo setpriv --reuid 3000 --egid 2000 --clear-groups id
uid=3000(u3000) gid=0(root) egid=2000(u2000) groups=2000(u2000)
  1. Incorrect User ID Handling in uutils id Command Issue: The uutils id command incorrectly displays user information when the effective group ID is changed, leading to inconsistencies with the expected output (pretty print & compact print). Test: add two users first
useradd -u 2000 u2000 -M
useradd -u 3000 u3000 -M

then

sudo setpriv --euid 3000 --egid 2000 --clear-groups target/release/id
uid=0(root) gid=0(root) euid=3000(u3000) egid=2000(u2000) groups=0(root)
sudo setpriv --euid 3000 --egid 2000 --clear-groups target/release/id -p
login    root
uid    root
euid    root
groups    u2000

Contributor guide

Tech stack
rust
Domain
cli
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic RustUnix user/group concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65
Research direction
The issue describes three bugs in the `id` command. The crash at line 503 of src/uu/id/src/id.rs is due to an unwrap() on a failed lookup; replace with proper error handling. For the group inconsistency, investigate how the effective group ID is handled compared to GNU coreutils. The third bug requires fixing the user ID display when euid/egid differ. Refer to GNU coreutils' `id` implementation for expected behavior.