This bug is created as a clone of upstream ticket:
https://fedorahosted.org/sssd/ticket/2487

How to reproduce:
 * configure sssd with ipa (ipa-client-install)
 * amend sssd configuration with following snippet
{{{
re_expression = (?P<name>[^@]+)@(?P<domain>[^@]+)
full_name_format = %1$s@%2$s
use_fully_qualified_names = True
}}}
 * try to obtain info about user
{{{
   getent passwd admin
}}}

The change can be related to views because there is a failure in sssd_nss.log
(the request was not populated to backend due to this failure)

{{{
[nss_cmd_getbynam] (0x0400): Running command [17] with input [admin].
[sss_parse_name_for_domains] (0x0200): name 'admin' matched expression for domain 'ipa.domain', user is admin
[nss_cmd_getbynam] (0x0100): Requesting info for [admin] from [ipa.domain]
[sss_ncache_check_str] (0x2000): Checking negative cache for [NCE/USER/ipa.domain/admin]
[nss_cmd_getpwnam_search] (0x0100): Requesting info for [admin]
[sysdb_getpwnam_with_views] (0x0040): sysdb_getpwnam failed.
[nss_cmd_getpwnam_search] (0x0020): Failed to make request to our cache!
[reset_idle_timer] (0x4000): Idle timer re-set for client [0x7f582f90fbb0][20] 
[reset_idle_timer] (0x4000): Idle timer re-set for client [0x7f582f90fbb0][20] 
[client_recv] (0x0200): Client disconnected!
[client_destructor] (0x2000): Terminated client [0x7f582f90fbb0][20]
}}}

It is not visible in sssd_nss log file, but function ''sysdb_getpwnam'' failed because it called function ''sss_get_domain_name'' which returned ''NULL''.