puppet lookup --facts <json file> can't modify $facts hash

I was trying to simulate a change to my $facts['networking'] fact, so I ran facter --json > ~/Desktop/facts.json, edited the appropriate spot, and tried to pass that to puppet lookup --facts. No dice: my change was ignored.

That's because I was using facts.networking in my hierarchy, and apparently --facts doesn't actually set the $facts variable — it just sets top-scope variables with names from the JSON.

• Problem one: That's unexpected, and it interferes with using facter --json as a basis for simulating other nodes.

So, I tried wrapping the facts json in another object with only a "facts": key. Which resulted in the following error: "Error: Could not run: Attempt to assign to a reserved variable name: 'facts'"

• Problem two: If your hierarchy uses the $facts variable like we recommend (instead of ::factname vars), it's impossible to simulate any changes with the puppet lookup CLI. I expect this blocks setting other values for $trusted or $server_facts, as well.

The first problem goes into the bucket of things we need to discuss around puppet lookup's UX. The second problem seems like a straight-up defect.