id returns wrong exit code when user does not exist

[peter-englmaier]

We noticed, that id return exit code 1, when user is not found. This can happen inside docker and can cause startup scripts to fail. Please revert to the old behavior.

This is what happens with the uutils version (i.e. with docker image ubuntu:latest):

root@ea03ae12c436:/# id
id: cannot find name for group ID 1234
id: cannot find name for group ID 1234
uid=0(root) gid=1234(1234) groups=1234(1234)
root@ea03ae12c436:/# echo $?
1

And this was the old behavior (i.e. with docker image ubuntu:noble):

root@a0d7473d7858:/# id
uid=0(root) gid=1234 groups=1234
root@a0d7473d7858:/# echo $?
0

[mhutter]

I think the behavior here is different from GNU coreutils: In GNU, the error message mentioned in the report is only ever printed when -u, -g or -G is specified together with -n:

$ docker run -it --rm --user 0:1234 --entrypoint=/bin/bash docker.io/library/ubuntu:noble -c 'id; echo $?; echo "==="; id -g -n; echo $?'
uid=0(root) gid=1234 groups=1234
0
===
id: cannot find name for group ID 1234
1234
1

Compared to uutils:

docker run -it --rm --user 0:1234 --entrypoint=/bin/bash docker.io/library/ubuntu:latest -c 'id; echo $?; echo "==="; id -g -n; echo $?'
id: cannot find name for group ID 1234
id: cannot find name for group ID 1234
uid=0(root) gid=1234(1234) groups=1234(1234)
1
===
id: cannot find name for group ID 1234
1234
1