(maint) replace legacy facts in service provider

[bastelfreak]

This causes issues with spec testing puppet modules on a regular basis.
It's not guaranteed that new factsets from facterdb have legacy facts
because, well, Puppet Inc declared them legacy and in many places they
are opt-in. We (Vox Pupuli) spent alot of time adding some legacy facts
back to some factsets, but it's inconsistent. I think they shouldn't be
used anymore.

[puppetlabs-jenkins]

Can one of the admins verify this patch?

[bastelfreak]

I'm not really sure how to mock the structured facts in rspec :(

[b4ldr]

I'm not really sure how to mock the structured facts in rspec :(

not pretty but this is what i have done in the past

Also worth pointing out FACT-2913

[joshcooper]

We tried doing this earlier and had to revert back because it broke tests that were only stubbing the legacy fact, but not the equivalent structured fact. So I don't think this is something that can land in a 7.x release.

Also Puppet recently added the ability to inject a facter implementation, see (PUP-11216). When using puppet as a library, such as when testing a module, it's now possible for rspec-puppet to do something like this:

facts = load fact fixtures, e.g. from https://raw.githubusercontent.com/voxpupuli/facterdb/master/facts/4.2/almalinux-8-x86_64.facts
facter_impl = TestFacterImpl.new(facts)
Puppet.initialize_settings(['arg1', 'arg2', ..], true, true, {facter: facter_impl})

This way the test can completely stub whatever facts are needed for the test. One exception is if a module's type/provider is calling Facter.value directly. If so, the module should be updated to call Puppet.runtime[:facter].value(:somefact) instead to ensure we can intercept the lookup.

I think the path forward would be something like:

1. Ensure facterdb contains fixtures with both legacy and structured facts
2. Update rspec-puppet to pass in a facter implementation that only uses facterdb to resolve facts (this works in 6.25.0/7.11.0 and up)
3. Update rspec-puppet to issue deprecation warnings if a module tries to call Facter.value directly
4. In Puppet 8, switch puppet to confine providers based on structured facts only.

Thoughts?

/cc @binford2k

[binford2k]

At least the starts of the test implementation went in with puppetlabs/rspec-puppet#16

I did a quick scan and here's a list of all the Forge modules that invoke Facter.value directly. https://docs.google.com/spreadsheets/d/1O3sE8xsCFat2uYgb-4fAyu02ctYCZ78VoRXzDsAn4-k/edit#gid=565587507

If we wanted to, I could script out an "update the world" bot to propose PRs to the new API.

[bastelfreak]

@joshcooper

We tried doing this earlier and had to revert back because it broke tests that were only stubbing the legacy fact, but not the equivalent structured fact. So I don't think this is something that can land in a 7.x release.

you say that "just" because it's time consuming to update the tests? It shouldn't be a breaking change, or am I missing something?

@binford2k if the bot can provide a working PR, I'm +100000 for that.

[joshcooper]

Thanks @bastelfreak We ended up fixing this in 82cef23 so I'm going to close this.