[R-pkg-devel] CRAN packages suggesting other packages but not using them conditionally

[Duncan Murdoch]

On 12/12/2020 4:41 p.m., Ben Bolker wrote:
> 
> 
> On 12/12/20 4:08 PM, Spencer Graves wrote:
>> Hi, Ben et al.:
>>
>>
>> On 2020-12-12 13:43, Ben Bolker wrote:
>>>     Apologies if I'm telling you something you already know:
>>>
>>>     By default, fda::CRAN() uses the presence of environment variables
>>> matched by the regexp "^_R_" as a heuristic to decide whether it's
>>> being running on CRAN.
>>>
>>>     testthat::skip_on_cran()  calls testthat::on_cran() to look for an
>>> environment variable called NOT_CRAN equal to "true". The
>>> devtools::check() machinery automatically sets this variable.
>>
>>
>>   > testthat::on_cran
>> Error: 'on_cran' is not an exported object from 'namespace:testthat'
> 
>        on_cran() is intended to be used via testthat::skip_on_cran()
> (which is exported, unlike on_cran()).
>>
>>
>>         Besides, on my Mac, I get:
>>
>>
>>   > testthat:::on_cran()
>> [1] TRUE
>>
>>
>>         My Mac is NOT CRAN, and I don't want that function to return TRUE
>> on my computer unless I explicitly run "R CMD check --on-cran".
> 
>     The assumption of testthat is that it's going to be deployed via
> devtools::check(), which automatically sets the environment variable
> NOT_CRAN equal to 'true'. For testing on your machine, you could use
> 
> Sys.setenv(NOT_CRAN="true"); testthat:::on_cran()
> 
> or you could put
> 
> export NOT_CRAN=true
> 
> in the shell/in your testing pipeline.
> 
> 
>>
>>
>>>     So: fda::CRAN() depends on breakable assumptions, defaults to FALSE
>>> in an empty environment.  skip_on_cran() defaults to TRUE in an empty
>>> environment (but defaults to FALSE in a devtools::check() environment).
>>
>>         If future changes break fda::CRAN, I will have to deal with it then.
>>
>>
>>         I'd be happier if the CRAN maintainers would develop a procedure
>> to make it easier for package maintainers do two things:
>>
>>
>>               * Include tests in their package that run longer than the
>> time limit permitted on CRAN.
>>
>>
>>               * Give error messages that the package maintainer wants to
>> see but that should be suppressed on CRAN or when the user decides to
>> run "R CMD check --as-cran".
> 
>    I agree that this would be nice.
> 
>     A simple mechanism would be to set an official/sanctioned/stable
> environment variable such as _R_ON_CRAN in all CRAN testing pipelines.

What's wrong with users setting NOT_CRAN on all non-CRAN testing pipelines?

Most people want the same tests in both places.  Those who like writing 
lots of time consuming tests are the ones who shouldn't mind a small 
step to control them.

Duncan Murdoch