Artifactory generates PACKAGES files with the unfortunate combination of windows newlines an empty blank line at the end. The latter likely for compatibility with debian Packages files (RTFACT-12881). It seems unlikely that we could get Artifactory to change this behavior in a reasonable amount of time. If the PACKAGES file does not use windows newlines or if it does use windows newlines and there is not a blank line at the end the file is parsed as expected.

Unfortunately currently pkgcache does not parse these files with both windows newlines and a trailing blank line properly and after dd5a590 now throws errors in this case instead of a warning.

Would it be possible for pkgcache to handle this case?

You can reproduce the issue without needing access to an Artifactory instance with

lines <- readLines("http://cloud.r-project.org/src/contrib/PACKAGES")
writeLines(c(lines, ""), "PACKAGES", sep = "\r\n")
pkgcache::parse_packages("PACKAGES")
#> Error in pkgcache::parse_packages("PACKAGES") :
#>  PACKAGES file ended while parsing a key @lib.c:481 (pkgcache_parse_packages_raw)