>> Recommends: only gets installed, can be used via if(requireNamespace()) >> from the package and in pkg tests[1] [snip] >> Build-Depends: gets installed before build, removed after. >> Suggests: only installed when requested at install.packages() and only >> used in examples/vignettes.
[snip] > I'd much rather > have a way of declaring explicitly the different aspects of dependence > on a package rather than bundling them up into cute labels, Agreed > but it's too late for that now. However, we don't need to make things worse. Disagreed. We could follow the well-established practices of Debian (and CRAN already does that, partially). >> If 'tons of packages' are using if(requireNamespace) in their package >> code there seems to be a need for something like this. [snip] > I don't follow the argument here. What problem are you solving? Basically I'm trying to address the idea suggested by Thomas, who started this conversation, and make it a bit more explicit. I felt that the discussion went a little off-track there. Right now, when package code (not examples) uses a suggested package, part of that package will by default not work - at least that's how people use it now. I would like it to work by default. For examples/vignettes you could be more forgiving since running an example is not core functionality of a package. >> Perhaps more controversially a 'Breaks' field could be considered. [snip] > This isn't controversial, it's just a bad idea. Don't encourage people > to break things. Your reaction just proved my point about it being controversial. More seriously, real progress is hardly ever possible without breaking things, so I think at least people could have a serious discussion about it before dismissing it simply as a bad idea. The Debian community obviously once thought it was a good idea, so why not discuss it for R/CRAN? (discussions are also an important way to progress even if no line of code is changed). At the moment, I'm inclined against the idea, but I for one like to see me proven wrong. >> [1] actually, once we know a pkg is Recommended, the >> 'if(requireNamespace)' could even be absorbed in the :: operator. >I don't see how :: would be any different than it is now. If you don't >have foo available, and you try to use foo::bar(), what would happen >other than an error? I think you're right there. <resets brain>. Best, Mark Op wo 3 aug. 2016 om 13:41 schreef Duncan Murdoch <murdoch.dun...@gmail.com >: > On 03/08/2016 5:32 AM, Mark van der Loo wrote: > > > > After reading the link in Dirk's initial reply, how about adding fields > > 'Recommends' and 'Build-Depends' to DESCRIPTION as in Debian? > > > > Recommends: only gets installed, can be used via if(requireNamespace()) > > from the package and in pkg tests[1]. [Debian: The Recommends field > > should list packages that would be found together with this one in all > > but unusual installations.] > > Build-Depends: gets installed before build, removed after. > > Suggests: only installed when requested at install.packages() and only > > used in examples/vignettes. > > I think the distinction between Recommends and Suggests is too subtle > here. I already think it's a bad thing that we are using these words in > ways that don't really correspond to English usage. I'd much rather > have a way of declaring explicitly the different aspects of dependence > on a package rather than bundling them up into cute labels, but it's too > late for that now. However, we don't need to make things worse. > > > > > If 'tons of packages' are using if(requireNamespace) in their package > > code there seems to be a need for something like this. Compliance to the > > above can be checked automatically and a gradual implementation via > > NOTE->WARNING->ERROR in R CMD check seems possible. > > I don't follow the argument here. What problem are you solving? > > > Perhaps more controversially a 'Breaks' field could be considered. There > > are a few packages out there that have many, many, dependencies. > > Implementing breaking updates currently depends on the willingness of > > many authors to update their package or convincing the CRAN maintainers > > to allow for (temporary) breakage. > > This isn't controversial, it's just a bad idea. Don't encourage people > to break things. > > > The suggestion to have functions auto-install things is very > > inconvenient for the good reasons pointed out by Thomas. Additionally, > > it is often based on the wrong assumptions. Example: the RGtk2 package > > has this habit of trying to install when libgtk2 is not on the path. But > > in my case that is often exactly the case: it is just not on the path > > (libgtk2 is on the network, the VM just doesn't know yet). So I'd rather > > have a proper and accurate error message (which is good practice anyway). > > > > > > Best, > > Mark > > > > [1] actually, once we know a pkg is Recommended, the > > 'if(requireNamespace)' could even be absorbed in the :: operator. > > I don't see how :: would be any different than it is now. If you don't > have foo available, and you try to use foo::bar(), what would happen > other than an error? > > Duncan Murdoch > > > > > > > > > > > Op wo 3 aug. 2016 om 01:46 schreef Duncan Murdoch > > <murdoch.dun...@gmail.com <mailto:murdoch.dun...@gmail.com>>: > > > > On 02/08/2016 6:34 PM, Dirk Eddelbuettel wrote: > > > > > > On 2 August 2016 at 18:13, Duncan Murdoch wrote: > > > | Okay, now I think I understand, but I agree with CRAN. It is not > > > | feasible to tell if the test happened somewhere in the code > > unless we > > > | enforce a particular way of writing the test. > > > > > > Debian has well over 20k packages, and they are tested this way. > > You just > > > need to show the will of testing in an _empty_ environment to > ensure > > > _everything_ that is needed is loaded. > > > > > > | I would object if I had to write if (requireNamespace("foo")) > > multiple > > > | times just to satisfy CRAN's test, when any sane human could > > tell that > > > | the first test was sufficient. > > > | > > > | For example, if my package Suggests: foo, I should be able to > write > > > | > > > | if (!requireNamespace("foo")) > > > | stop("Package foo is needed for this example") > > > | > > > | and then merrily call foo::bar() as many times as I like. > > > | > > > | Or am I still misunderstanding you? What particular thing > > should CRAN > > > | change? > > > > > > You seem to misunderstand that both you and I want > > > > > > if (!requireNamespace("foo")) > > > stop("Package foo is needed for this example") > > > > > > (or alternative per-call tests) and that CRAN does not enforce > either. > > > > > > CRAN, like Hadley, just closes its eyes, swallows hard, and then > > simply loads > > > everything treating Suggests as if it were Depends. > > > > > > But it ain't. Suggests != Depends. > > > > > > Now clearer? > > > > > > So really what you're suggesting is that CRAN should run tests with > the > > suggested packages absent. Presumably tests should also be run with > > them present. > > > > But if they did that, the code that I want to write would call stop() > > and fail. So we'd need some way to say "Let the user know they need > > 'foo' to run this, but don't fail." And we'd need to phase this in > > really gradually, because tons of packages are using code like my > > example. > > > > You volunteered to help CRAN package checking. Why not put together > > code to implement your idea, and see how big the problem would be to > > phase it in, by seeing how many packages fail under it? > > > > Duncan Murdoch > > > > ______________________________________________ > > R-package-devel@r-project.org <mailto:R-package-devel@r-project.org> > > mailing list > > https://stat.ethz.ch/mailman/listinfo/r-package-devel > > > > [[alternative HTML version deleted]] ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
