Should we autogroup two files with the same name but compatible params?

[purpleidea]

If you had:

file "/tmp/foo" {
        state => "exists",
        mode => "ug=rw,o=",
}

file "/tmp/foo" {
        state => "exists",
        owner => "james",
}

What should happen? Should it error because they're not CompatibleRes or should it merge them and use both params?

What about?

file "/tmp/foo" {
        state => "exists",
        mode => "u=rw", # note the user mode
}

file "/tmp/foo" {
        state => "exists",
        mode => "g=rw", # note the group mode
}

Should even the mode parameter be merged?

Perhaps the solution is to error, perhaps the solution is to merge, and perhaps the solution is to even have a resource-specific param that sets how flexible we are with merging?

In any case we won't proceed before we:

1. Have a legitimate, non-xy use-case that would benefit from this.
2. Double check and add tests that when we merge we combine both the sets of edges into the new grouped resource correctly.