building a miniCRAN 3.4 using R 3.6

[Courvoisier13]

I am using 3.6.1 and building a miniCRAN for R 3.4.4.

The new packages get added correctly and build a miniCRAN for R 3.4.4 correctly. However, when trying to install packages from the miniCRAN using the R 3.4.4 I get the error

   Warning in install.packages :
    unable to access index for repository https://cran.rstudio.com/src/contrib:
    cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'

  Installing packages into ‘D:/libraries/R/libraries’ (as ‘lib’ is unspecified)
  Error in install.packages : cannot read workspace version 3 written by R 3.6.1; need R 3.5.0 or newer

I found the issue and it was the index stored as RDS version 3

  > readRDS("path/miniCRAN3.4/bin/windows/contrib/3.4/PACKAGES.rds")
  Error in readRDS("path/miniCRAN3.4/bin/windows/contrib/3.4/PACKAGES.rds") : 
    cannot read workspace version 3 written by R 3.6.1; need R 3.5.0 or newer

So I read the file in R 3.6, and overwrote it with writeRDS(, version = 2) and that solved the issue and I was able to install the packages in R 3.4.

So miniCRAN puts the right version of the libraries in the folder, but the index is an .rds and that is no longer compatible by default across R=<3.5 to R>=3.6

[achubaty]

we are using write_packages as a wrapper for tools::write_PACKAGES to create the PACKAGES files. To work around this (within write_packages) using the approach suggested above, we would need to add an argument to pass in the Rversion.

[Courvoisier13]

Hi, I actually solved the issue by setting env variable R_DEFAULT_SAVE_VERSION = 2 and R_DEFAULT_SERIALIZE_VERSION = 2. This way the .rds gets saved as version 2 (pre R 3.5). It's not ideal but it works while the team makes the switch.

[achubaty]

@andrie we should add this to an example/vignette. I'll add it to my to do list, but I don't know when I'll get to it.

[andrie]

I'm adding an r_version argument to write_packages. (Now in the process of fixing the errors this introduces!)

[lucazav]

I've just created a miniCRAN repository for an offline installation of R 3.4.4 using R 4.2.2. I installed the dev version of miniCRAN to be sure that the upon mentioned commit was included (its version is 0.2.16.9000). Here the code to create the repository using R 4.2.2:

library("miniCRAN")

# Reference the CRAN 0-Clud mirror
CRAN_mirror <- c(CRAN = "https://cloud.r-project.org")

# Declare the packages' destination folder in your local machine
# and create it
local_repo <- "C:/miniCRAN_R344"
dir.create(local_repo)

# Declare the packages you want to install (they can be more than one)
pkgs_needed <- c("ggplot2")

# Reference the package dependencies and add them to the packages declaration
pkgs_with_dependencies <- pkgDep(pkgs_needed, repos = CRAN_mirror)

# Download all packages with version compatible with the engine R 3.4.4 
makeRepo(pkgs_with_dependencies, path = local_repo,
         repos = CRAN_mirror,
         type = "win.binary",
         Rversion = "3.4.4")

When trying to install packages in R 3.4.4, I'm getting the following error:

Error in readRDS(dest) :
cannot read workspace version 3 written by R 4.2.2; need R 3.5.0 or newer

Does the above commit still need to be committed?

[andrie]

That commit was merged a long time ago, but it's clear that it didn't solve the root cause.

As a workaround I suggest you either use R-3.5 or earlier to create the miniCRAN, or use the advice earlier in this thread (#129 (comment))

[andrie]

The earlier supposed "fix" that I wrote didn't work at all. I also couldn't get the proposed workaround to work as expected.

After some experimentation, I realised it's quite trivial to use tools::write_PACKAGES() to write the .rds file, then read it into memory and write it out again, but this time using version = 2.

I have this working in my local main branch and will commit this soon.

[andrie]

Can we close this now?