Change the namespace-only compliance check

[MichaelChirico]

DBItest/R/spec-compliance-methods.R

Lines 52 to 53 in f19fb4d

	#' All methods defined in \pkg{DBI} are reexported (so that the package can
	#' be used without having to attach \pkg{DBI}),

I think the reasoning here is faulty, and can see reasons why it's not a great idea (e.g. any analyst needing >1 such "compliant" backend in their script will be greeted with a flood of "masked in global environment" packageStartupMessages).

The crux of the comment seems to be we want to test that RMyBackend:: form works, which only requires that {RMyBackend}'s NAMESPACE has the appropriate importClassesFrom() directives. Should we change this test to check the NAMESPACE instead?

[krlmlr]

I'm ready to revisit the reexport requirement, perhaps Depends: DBI isn't such a bad idea after all? This seems to work well enough for duckplyr.

CC @hadley.

[MichaelChirico]

Oh, I think I misunderstood the purpose. Usually I am just running library(DBI), but sometimes I just do DBI::dbConnect() for the handful of direct names I need.

As much as I hate Depends, if the requirement really is "all {DBI} names should be visible", that is a better way to go IMO, again because it's not unheard of to have multiple SQL backends required for a single script, and cluttering up the logs with loads of 'masked exports' messages seems a bit undesirable. Depends solves that of course because the second library(<RDBIUser>) will skip attaching {DBI}.

I can quickly find hits library(A); library(B) for the first pair of R* downstreams of {DBI} I tried:

https://github.com/search?q=lang%3AR%20%2Flibrary%5C(RMariaDB%5C)%2F%20%2Flibrary%5C(RSQLite%5C)%2F&type=code

[hadley]

My preferred style is this:

library(DBI)
con <- dbConnect(RSQLite::SQlite())

since in many cases you'll only need the backend for a single function.

So IMO the backends neither need to export an DBI generics nor depend on DBI. I think Depends: DBI can be left up to the individual maintainer, but I agree with @MichaelChirico that backends shouldn't re-export any generics.