Do not use the alternative Archive URL on PPM

[gaborcsardi]

Because sometimes PPM serves a source package there, while serving a binary at the proper URL:

! error in pak subprocess
Caused by error in `verify_extracted_package(filename, pkg_cache)`:
! 
'/tmp/RtmpraRRfO/file10aed93d50/src/contrib/x86_64-pc-linux-gnu-ubuntu-22.04/4.4/later_1.3.2.tar.gz'
is not a valid binary, it is missing later/Meta/package.rds.

pak only uses the alternative URL for a repo named 'CRAN', so a workaround is to name your repo something else, e.g. 'PPM' seems appropriate.

[gaborcsardi]

We only use it if the repo is called CRAN, but that's not enough, because people sometimes use PPM with the name CRAN.

[gaborcsardi]

This needs to be fixed somewhere here: https://github.com/r-lib/pkgcache/blob/c227fe90b20959ac0d3f4e8a2897ed9117f70ee0/R/packages-gz.R#L311
Maybe we can filter based on the URL, e.g. if the URL contains __linux__. It should only matter on Linux, on other platforms we don't use the Archive.

[alethor]

I'm slightly confused about how this workaround works, could you give a concrete example?

[gaborcsardi]

@alethor

> options(repos = c(CRAN = "https://packagemanager.posit.co/cran/__linux__/jammy/latest"))

> pak::pkg_install("hommel")
✔ Updated metadata database: 3.70 MB in 9 files.
✔ Updating metadata database ... done

→ Will install 1 package.
→ Will download 1 package with unknown size.
+ hommel   1.6 [dl]

ℹ Getting 1 pkg with unknown size
✔ Got hommel 1.6 (x86_64-pc-linux-gnu-ubuntu-22.04) (11.43 kB)
✔ Downloaded 1 package (11.43 kB) in 1.3s
Error:
! error in pak subprocess
Caused by error in `verify_extracted_package(filename, pkg_cache)`:
! /tmp/RtmpZFurxM/file31416a7e1f/src/contrib/x86_64-pc-linux-gnu-ubuntu-22.04/4.4/hommel_1.6.tar.gz is not a valid binary, it is
missing hommel/Meta/package.rds.
Type .Last.error to see the more details.

OTOH:

> options(repos = c(PPM = "https://packagemanager.posit.co/cran/__linux__/jammy/latest"))
> pak::pkg_install("hommel")
✔ Updated metadata database: 4.79 MB in 4 files.
✔ Updating metadata database ... done

→ Will install 1 package.
→ Will download 1 package with unknown size.
+ hommel   1.6 [dl]

ℹ Getting 1 pkg with unknown size
✔ Got hommel 1.6 (x86_64-pc-linux-gnu-ubuntu-22.04) (206.95 kB)
✔ Downloaded 1 package (206.95 kB) in 1.1s
✔ Installed hommel 1.6  (1s)
✔ 1 pkg + 1 dep: kept 1, added 1, dld 1 (206.95 kB) [10.9s]

[gaborcsardi]

This is now fixed in the nightly builds, install like this: https://pak.r-lib.org/reference/install.html#nightly-builds