[Bug]: build_threads_per_core resolver broken

[mpldr]

Is this a critical security issue?

• This is not a security issue.

Describe the Bug

[2026-03-03 12:57:04.631039 ] ERROR Facter::Resolvers::Linux::Lscpu - Resolving fact threads_per_core, but got undefined method 'split' for nil at /usr/lib/ruby/gems/3.4.0/gems/openfact-5.5.0/lib/facter/resolvers/linux/processors_lscpu.rb:34:in 'Facter::Resolvers::Linux::Lscpu.build_threads_per_core' 
[2026-03-03 12:57:04.633205 ] ERROR Facter::Resolvers::Linux::Lscpu - Resolving fact cores_per_socket, but got undefined method 'split' for nil at /usr/lib/ruby/gems/3.4.0/gems/openfact-5.5.0/lib/facter/resolvers/linux/processors_lscpu.rb:34:in 'Facter::Resolvers::Linux::Lscpu.build_threads_per_core' 

Expected Behavior

No errors are shown during execution.

Steps to Reproduce

$ docker run -it alpine:3.22 ash
# apk add ruby ruby-dev ruby-racc
# gem install openfact
# facter
[2026-03-03 13:00:55.066579 ] ERROR Facter::Resolvers::Linux::Lscpu - Resolving fact threads_per_core, but got undefined method 'split' for nil at /usr/lib/ruby/gems/3.4.0/gems/openfact-5.5.0/lib/facter/resolvers/linux/processors_lscpu.rb:34:in 'Facter::Resolvers::Linux::Lscpu.build_threads_per_core' 
[2026-03-03 13:00:55.069027 ] ERROR Facter::Resolvers::Linux::Lscpu - Resolving fact cores_per_socket, but got undefined method 'split' for nil at /usr/lib/ruby/gems/3.4.0/gems/openfact-5.5.0/lib/facter/resolvers/linux/processors_lscpu.rb:34:in 'Facter::Resolvers::Linux::Lscpu.build_threads_per_core' 
disks => {
  nvme0n1 => {
    model => "BC711 NVMe SK hynix 512GB",
    size => "476.94 GiB",
    size_bytes => 512110190592,
    type => "ssd"
  }
}
… omitted for brevity …

Environment

facter Version: 5.5.0
Platform: Alpine 3.22
Ruby: ruby 3.4.4 (2025-05-14 revision a38531fd3f) +PRISM [x86_64-linux-musl]

Additional Context

No response

Relevant log output

[corporate-gadfly]

I'm not very good with ruby, but the I was able to reproduce.

The following facter --debug output may be able to help in solving this:

2026-03-06 01:43:35.488850 ] DEBUG Facter::Resolvers::Linux::Lscpu - Command lscpu | grep -e 'Thread(s)' -e 'Core(s)' completed with the following stderr message: sh: lscpu: not found 
[2026-03-06 01:43:35.488958 ] ERROR Facter::Resolvers::Linux::Lscpu - Resolving fact threads_per_core, but got undefined method 'split' for nil at /usr/lib/ruby/gems/3.4.0/gems/openfact-5.5.0/lib/facter/resolvers/linux/processors_lscpu.rb:34:in 'Facter::Resolvers::Linux::Lscpu.build_threads_per_core' 
[2026-03-06 01:43:35.489038 ] DEBUG Facter::Core::Execution::Posix - Executing command: lscpu | grep -e 'Thread(s)' -e 'Core(s)' 
[2026-03-06 01:43:35.490870 ] DEBUG Facter::Resolvers::Linux::Lscpu - Command lscpu | grep -e 'Thread(s)' -e 'Core(s)' completed with the following stderr message: sh: lscpu: not found 
[2026-03-06 01:43:35.490945 ] ERROR Facter::Resolvers::Linux::Lscpu - Resolving fact cores_per_socket, but got undefined method 'split' for nil at /usr/lib/ruby/gems/3.4.0/gems/openfact-5.5.0/lib/facter/resolvers/linux/processors_lscpu.rb:34:in 'Facter::Resolvers::Linux::Lscpu.build_threads_per_core'

[corporate-gadfly]

Should be fixed on alpine with:

apk add lscpu