[Rd] Packages manually setting NeedsCompilation

[Michael Dewey]

This is all a bit above my head but as a Windows user I have always 
interpreted NeedsCompilation as meaning I could install it without 
having to wait for binaries to appear on CRAN. I do not need Rtools for 
my own packages so I have never installed it.

Michael

On 17/05/2025 09:13, Iñaki Ucar wrote:
> El sáb., 17 may. 2025 4:03, Hervé Pagès <hpages.on.github using gmail.com>
> escribió:
> 
>> FWIW NeedsCompilation is a misnomer. IIRC when I was discussing this
>> feature with R core members many years ago, it doesn't only flag
>> packages that require compilation (and thus contain arch-specific binary
>> files), but it is more generally intended to flag packages that the user
>> wouldn't be able to install **from source** on a pristine Windows or Mac
>> system because the installation process depends on tools that are not
>> necessarily present on such systems.
>>
>> For example I think I remember seeing at the time some packages that
>> were using 'make' for non-compilation related business. These packages
>> still needed to be flagged with 'NeedsCompilation: yes' in order to
>> recognize them as packages for which "binaries" needed to be made for
>> the purpose distributing them.
>>
> 
> Then maybe such thing shouldn't be allowed?
> 
> Iñaki
> 
> 
>> Packages without 'NeedsCompilation' field (or with 'NeedsCompilation:
>> no') don't need binaries because the source tarballs is guaranteed to be
>> installable on **any** system, in particular on systems that don't have
>> any development tools.
>>
>> Best,
>>
>> H.
>>
>> On 15/05/2025 03:38, Iñaki Ucar wrote:
>>> On Thu, 15 May 2025 at 11:42, Jeroen Ooms <jeroenooms using gmail.com> wrote:
>>>> On Wed, May 14, 2025 at 11:05 PM Simon Urbanek
>>>> <simon.urbanek using r-project.org> wrote:
>>>>> Can you give an example, please? I wonder if there is a real use-case
>> or just bad package design.
>>>> The case that bit me yesterday was a Bioconductor package Rigraphlib,
>>>> see
>> https://bioconductor.org/packages/release/bioc/src/contrib/Rigraphlib_1.0.0.tar.gz
>>>>
>>>> This package builds a static library entirely from a configure script.
>>>> Because there is no 'src' dir, we assumed the package to be all-arch,
>>>> and get linking errors when trying to use it on another arch then it
>>>> was built for. Arguably this is indeed bad package design, but that is
>>>> hard to protect against.
>>> The opposite case is also true: there is a src directory but no
>>> compilation happens. This is a problem for deb/rpm shipment for two
>>> reasons. In rpm packaging at least, archful packages are inspected to
>>> extract debuginfo; since there is no compiled output there, this fails
>>> and the whole build fails. If the build succeeds (e.g. debuginfo is
>>> disabled), then we are building the same thing for all architectures,
>>> when there should be just one, noarch, for all.
>>>
>>> I can list at least 3 examples of this:
>>>
>>> - BANOVA: requires compilation, there is a src directory, nothing
>>> happens there, no source files, just a Makefile sitting there.
>>> - mixl: same, and the Makefile is just used to print if OpenMP is
>> supported (?).
>>> - mathjaxr: same, and the Makefile is used to install a javascript
>> library (!).
>>>
>>>>> I wouldn't think that should happen as configure is supposed to only
>> guide the compilation in src - if there is no src no binaries are expected
>> as the package did not provide any native sources hence there should be no
>> binary content. This looks like something that could be added to R CMD
>> check?
>>>> In that case maybe R should warn if it runs a package configure script
>>>> but there is no "src"? And check if NeedsCompilation: yes is set?
>>>>
>>>> One way or another, what matters is that when R runs configure or make
>>>> during install, the value in the "Built" field in the binary package
>>>> should contain the platform value. This is also important when distros
>>>> ship R packages in deb or rpm format, to prevent packages that have
>>>> compiled code from getting "Architecture: all" and be installed on the
>>>> wrong platforms.
>>> IMHO, the flag NeedsCompilation in the DESCRIPTION file should be the
>>> one and only source of truth here, regardless of the presence or not
>>> of a src directory. Then I see two paths here:
>>>
>>> - Either the developer is responsible for setting this flag, and the R
>>> CMD check should fail if it's yes but no compilation happens or the
>>> other way around.
>>> - Or R CMD build is responsible for setting this flag after checking
>>> if compilation happens or not.
>>>
>> --
>> Hervé Pagès
>>
>> Bioconductor Core Team
>> hpages.on.github using gmail.com
>>
>>
> 
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-- 
Michael Dewey