r-ver has python3 installed ... should it?

[mmuurr]

Container image name

rocker/r-ver:4.0.3

Container image digest

rocker/r-ver@sha256:c058532fe0273a5cb37898966a85b7df21e228b68158d4bcffb59fe5ec7b7767

What operating system are you seeing the problem on?

macOS

System information

No response

Bug description

rocker/r-ver:4.0.3 seems to have python3 already installed, but when walking through the Dockerfiles and stack JSON files, it looks to me like that's unintended. I only discovered this when trying to install python3 myself on top of this image and found a version mismatch. More evidence suggesting this is unintended:

1. ubuntu:focal (r-ver's base layer) does not have python3 installed.
2. The repo's README says, "Adds cuda and Python to 'r-ver'" (suggesting Python) is not expected to be part of r-ver.

Perhaps this is intended?

How to reproduce this bug?

docker run -it --rm rocker/r-ver:4.0.3 python3 --version

[eitsupi]

I think this is a documentation issue.
rocker/r-ver seems to install python3 at the following location (devscripts).

rocker-versioned2/scripts/install_R_source.sh

Lines 34 to 37 in bfecf9e

	apt-get install -y --no-install-recommends \
	bash-completion \
	ca-certificates \
	devscripts \

https://packages.ubuntu.com/en/bionic/devscripts

But I don't understand why devscripts is here and what is really needed.

[benz0li]

@eitsupi Cross reference: rocker-org/rocker-versioned#166

[eitsupi]

@benz0li Thanks for sharing that. I am convinced.

[benz0li]

Added here: 7e065a9

[eitsupi]

Tracking this discussion, I see that rocker/drd doesn't like the devscripts dependencies (like python3) and only extracts checkbashisms and includes it in the source code.

rocker-org/rocker-versioned#167 (comment)
https://github.com/rocker-org/drd/blob/06ab465832ab7c77335d16f9e934d03bdb0493c4/checkbashisms

I suppose we could do the same thing here.

[eddelbuettel]

I had very much forgotten about that but yes -- I noticed that to run checkbashishm I didn't need all the other parts, and the script itself was both small and stable (as in: no or few changes in recent years) so I guess I just 'vendored' it.

[eitsupi]

I have created a new issue #510 about the installation of devscripts.