Description of problem:
If one provides a list of groups containing a space, you get an error. This is easy to do when a shell script calls out to useradd with user-provided data (see for example bug #1126365).
Version-Release number of selected component (if applicable):
Inherent. (And documented in the man page.)
Steps to Reproduce:
1. sudo useradd foo --groups wheel,adm
2. sudo useradd bar --groups "wheel, adm"
First one works, but second says "useradd: group ' adm' does not exist".
Both should work -- strip leading or trailing spaces
groupadd does not permit the creation of groups containing spaces
We are not going to pursue this RFE at this point. If anyone wishes to work on this I'd suggest creating pull request on shadow upstream.