[R-pkg-devel] check cross-references error: Non-file package-anchored link(s)

[Gábor Csárdi]

On Sun, Jun 14, 2020 at 10:44 AM Duncan Murdoch
<murdoch.duncan using gmail.com> wrote:
[...]
>
> I think the argument was that static builds of the help pages would have
> trouble resolving the links.  With the current system, you can build a
> help page that links to a page in package foo even if package foo is not
> installed yet, and have the link work later after you install foo.

That is true, but it is also not a big problem, I think. The CRAN
Windows R installer does indeed build static help pages by default.
But the built-in web server that serves these works around broken
links by treating them as help topics instead of files. As you know.
:) So this would only be a problem if you wanted to serve the static
help pages with another web server. (Which is not a bad use case, but
then maybe Rd2HTML() can just resolve them as topics and avoid the
broken links.)

Btw. the problem of linking to the wrong page is even worse with
static builds of help pages, because if a link w/o a package (e.g.
\link{filter}) picks up the wrong package at install time, then the
wrong link is hard-coded in the html. If you are building binary
packages, then they will link to the wrong help pages.

WRE says that specifying the package in the link is rarely needed.
This was probably the case some time ago, especially when packages did
not have (compulsory) namespaces. But I am not sure if it still holds.
I would argue that it is better to specify the package you are linking
to. But the newly enforced requirement that we need to link to files
instead of topics makes this more error prone.

Gabor

[...]