[R-pkg-devel] Is using global assignment in package tests allowed?

I suppose, but this seems like kind of a far-fetched possibility if you're
following any sort of reasonable scripting/development practices. Why in
the world would someone be working with extremely valuable data and then
decide to run all my package's unit tests interactively in the same
session?

In any case, it sounds like I should either just skip these unit tests or
try to figure out what the heck is causing my namespace problems with
testthat.

On Thu, Jan 27, 2022 at 10:11 AM Duncan Murdoch <murdoch.duncan at gmail.com>
wrote:

On 27/01/2022 10:56 a.m., James Pustejovsky wrote:

But I am not using global variables at all in the package code (in
/R)---only for unit testing. Is this distinction relevant? Or do I need

to

avoid global assignment even in the unit tests?

CRAN may let you do what you are doing, but as Dirk and Jeff said, it
could come back to bite you later.  For example, you may create a
variable named foo containing extremely valuable data, and then run your
test.  (Tests can be run outside of R CMD check.)  If your test stomps
on foo, you'll lose all that data.

It's worth using some trick like Dirk's to avoid this possibility.

Duncan Murdoch

On Thu, Jan 27, 2022 at 9:40 AM Dirk Eddelbuettel <edd at debian.org>

wrote:

On 27 January 2022 at 07:20, Jeff Newmiller wrote:
| I don't know the answer to your question, but "beyond my ken"

doesn't

sound like a very convincing reason. Mucking with any environment that
isn't yours is asking for trouble... the behavior you depend on today

may

come into conflict with the code you are coordinating with when you

least

expect it.

Right on.

Yes a number of packages (of mine and other people) use a different
approach
to maintain 'global state' without ... using 'global variables' (==

bad).

The trick is something like `pkgenv <- new.env()` in R/zzz.R and to

then

also
set an option or two you need in .onLoad as eg  `pkgenv[["prefence"]]

<-

"foo"`
which you can later test for, alter, ... at will.

All without running afould of what `R CMD check --as-cran` may hate,

all

the
while maintaining your logic flow.

Dirk

--
https://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org

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