Pass --no-readline to R

[saraedum]

Conda and Gentoo (and apparently also ArchLinux and Debian) suffer from hangs when talking to R through the pexpect interface on the first invocation in a Sage session. It is unclear what is the underlying issue. Shortening Sage's R prompt seems to fix the issue as does passing --no-readline to R.

Is there any reason why we should keep readline support when talking to R with the pexpect interface? Otherwise, we should just pass on that flag even though we do not fully understand why it fixes that particular issue.

See conda-forge/sagelib-feedstock#19 (comment), and https://github.com/cschwan/sage-on-gentoo/blob/master/sci-mathematics/sage/files/dt-r-no-readline.patch.

CC: @kiwifb @antonio-rojas @infinity0 @jdemeyer @embray

Component: interfaces

Author: Ximin Luo, Julian Rüth

Branch: 9e6ea7e

Reviewer: Erik Bray

Issue created by migration from https://trac.sagemath.org/ticket/25806

[saraedum]

Branch: u/saraedum/25806

[saraedum]

Commit: 2d8f4bc

[saraedum]

Work Issues: is the patchbot happy?

[saraedum]

New commits:

2d8f4bc

Pass --no-readline to R otherwise Pexpect hangs

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

9e6ea7e

Link to #25806 to explain the --no-readline switch

[sagetrac-git]

Changed commit from 2d8f4bc to 9e6ea7e

[embray]

Reviewer: Erik Bray

[embray]

comment:5

This makes sense to me. There is a similar issue #25363 where it was needed to disable prompt_toolkit for Cantor's pexect interface to Sage to work (I believe Cantor is wrong to use pexpect to wrap Sage in the first place, but that's a different story).

I don't know why this would be a problem on some platforms but not others.

---

New commits:

9e6ea7e

Link to #25806 to explain the --no-readline switch

[saraedum]

Changed work issues from is the patchbot happy? to is the patchbot happy ⇒ positive review

[saraedum]

comment:6

Great. Let's wait for the patchbot to actually pass as I have not run doctests for this myself.

[sagetrac-tmonteil]

comment:7

#25503 does this already, and should ease downstream packaging (still needs review).

Replying to @embray:
[...]

I don't know why this would be a problem on some platforms but not others.

To what i understand, this is not a platform issue, but a version issue: our interface does not work with readline 7.

[saraedum]

Changed work issues from is the patchbot happy ⇒ positive review to none

[vbraun]

Changed branch from u/saraedum/25806 to 9e6ea7e

[saraedum]

comment:10

I might have misunderstood what the milestone stands for but I thought it would be the release of Sage that includes this. So, this is not in 8.3 yet but will only be in 8.4.

[saraedum]

Changed commit from 9e6ea7e to none