Installing local RPM files with either a dir:/foo repository or referring to
the .rpm file directly does not work:

90d2e3700912:/ # zypper in rpms/libalternatives1-1.2+3.b848aad-2.2.x86_64.rpm
Loading repository data...
Reading installed packages...
'_tmpRPMcache_:libalternatives1=0:1.2+3.b848aad-2.2' not found in package
names. Trying capabilities.
No provider of '_tmpRPMcache_:libalternatives1=0:1.2+3.b848aad-2.2' found.
Resolving package dependencies...
Nothing to do.
90d2e3700912:/ # zypper ar dir:/rpms dir
Adding repository 'dir'
....................................................................................................................................................................................................................[done]
Repository 'dir' successfully added

URI         : dir:/rpms
Enabled     : Yes
GPG Check   : Yes
Autorefresh : No
Priority    : 99 (default priority)

Repository priorities are without effect. All enabled repositories share the
same priority.
90d2e3700912:/ # zypper in libalternatives1
Building repository 'dir' cache
............................................................................................................................................................................................................[done]
Loading repository data...
Reading installed packages...
'libalternatives1' not found in package names. Trying capabilities.
No provider of 'libalternatives1' found.
Resolving package dependencies...
Nothing to do.
90d2e3700912:/ # zypper se -r dir
Loading repository data...
Reading installed packages...
No matching items found.

2022-02-07 12:54:48 <1> 90d2e3700912(358) [DEFINE_LOGGROUP++]
abstractspawnengine.cc(initEngineFromEnv):24 Starting processes via posix fork
2022-02-07 12:54:48 <1> 90d2e3700912(358) [DEFINE_LOGGROUP++]
forkspawnengine.cc(start):186 Executing 'repo2solv' '-o'
'/var/tmp/zypp.C5F1lq/zypper/_tmpRPMcache_/%SLV%/solv' '-X' '-R'
'/var/tmp/zypp.C5F1lq/zypper/_tmpRPMcache_/%CLI%'
2022-02-07 12:54:48 <1> 90d2e3700912(358) [DEFINE_LOGGROUP++]
forkspawnengine.cc(start):338 pid 360 launched
2022-02-07 12:54:48 <2> 90d2e3700912(358) [zypp]
RepoManager.cc(buildCache):1401   /usr/bin/find: No such file or directory
2022-02-07 12:54:48 <2> 90d2e3700912(358) [zypp]
RepoManager.cc(buildCache):1401   find: exit status 1
2022-02-07 12:54:48 <1> 90d2e3700912(358) [DEFINE_LOGGROUP++]
abstractspawnengine.cc(checkStatus):180 Pid 360 successfully completed

Looks like repo2solv needs a Requires: /usr/bin/find and proper error handling.

After installing findutils, both work:

90d2e3700912:/ # zypper in rpms/libalternatives1-1.2+3.b848aad-2.2.x86_64.rpm
Loading repository data...
Reading installed packages...
Resolving package dependencies...

The following NEW package is going to be installed:
  libalternatives1
...

90d2e3700912:/ # zypper -v ref -f dir
...
90d2e3700912:/ # zypper in libalternatives1
Loading repository data...
Reading installed packages...
Resolving package dependencies...

The following NEW package is going to be installed:
  libalternatives1