I tracked it down:
The cause is that:
(define (latest-bioconductor-package-version name)
"Return the version string corresponding to the latest release of the
bioconductor package NAME, or #F if the package is unknown."
actually returns #f. It's a bit said that this #f is not checked
further down. The problem is the package name. If you add an "r" before
the package name, it should work (suppose you fixed the first problem):
guix import cran --archive=bioconductor rtracklayer
Sorry for writing again on this topic.
Today I wanted to practice packaging an r package belonging to bioconductor, to then go on and read and work with texinfo.
After writing on IRC channel, I realized I already had this exact problem, but thought it was a problem of other packages.
I ran again this same command, and I am getting:
(and the backtrace is the same).
I am also new to schemas, but opened guix/import/cran.scm and saw what Bjorn was saying. I don't know why if it is not the latest package there should be a false condition, but I don't know either why I am not getting the latest version from bioconductor if it is real that, for tracklayer the latest is 42 and that file does not exist.
Any ideas? Should I spend more time trying to figure this out or should I move on to another task, like knowing guix more deeply or learning texinfo?