parse_known_intermixed_args() tests failing on CRAN's Debian GNU/Linux testing machines

[trevorld]

CRAN writes:

Dear maintainer,

Please see the problems shown on
https://cran.r-project.org/web/checks/check_results_argparse.html.

Please correct before 2024-12-07 to safely retain your package on CRAN.

Best wishes,
The CRAN Team

• Looking at the check pages it seems just the parse_known_intermixed_args() tests are failing on CRAN's Debian GNU/Linux testing machines
• I speculate those machines have a newer version of Python that returns a slightly different output with parse_known_intermixed_args(). Will need to install a newer version of Python and check.

[trevorld]

• locally compiled python3.12.5, python3.12.6, python3.12.7, and python3.13.0 from official sources and can't reproduce CRAN's issue with any of those.
• however can reproduce CRAN's issue running in the r-base rocker project docker container after running apt-get update && apt-get install python3 which seems to install python v3.12.7. Unsure why there is a difference between their Python v3.12.7 installed via apt and mine compiled locally (my local OS is an Ubuntu derivative which is a Debian derivative).

[trevorld]

library("argparse")
parser <- ArgumentParser()
parser$add_argument('--foo')
parser$add_argument('cmd')
parser$add_argument('rest', nargs='*', type='integer')
args <- strsplit('doit 1 --foo bar 2 3 -n 4', ' ')[[1]]
a_r <- parser$parse_known_intermixed_args(args)

Locally with Python v3.12.7 I see

> a_r
[[1]]
[[1]]$foo
[1] "bar"

[[1]]$cmd
[1] "doit"

[[1]]$rest
[1] 1 2 3


[[2]]
[1] "-n" "4" 

While in r-base with Python v3.12.7 (note the final "4" was put in [[1]]$rest instead of [[2]]):

> a_r
[[1]]
[[1]]$foo
[1] "bar"

[[1]]$cmd
[1] "doit"

[[1]]$rest
[1] 1 2 3 4


[[2]]
[1] "-n"

[trevorld]

Can see a difference in behaviour with underlying Python 3.12.7:

from argparse import ArgumentParser
import sys

parser = ArgumentParser()
parser.add_argument("--foo")
parser.add_argument("cmd")
parser.add_argument("rest", nargs="*", type=int)
args = ["doit", "1", "--foo", "bar", "2", "3", "-n", "4"]
a_r = parser.parse_known_intermixed_args(args)

print(a_r)
print(sys.version)

When run locally in Python 3.12.7:

(Namespace(foo='bar', cmd='doit', rest=[1, 2, 3]), ['-n', '4'])
3.12.7 (main, Nov 16 2024, 08:02:39) [GCC 11.4.0]

When run in r-base docker in Python 3.12.7 (probably similar to CRAN machine):

(Namespace(foo='bar', cmd='doit', rest=[1, 2, 3, 4]), ['-n'])
3.12.7 (main, Nov  8 2024, 17:55:36) [GCC 14.2.0]

[trevorld]

Weird, if I download the source for 3.12.7 in r-base and compile from source using ./configure ; make the error seems to go away--it seems to just be a problem with the binary provided by Debian Testing:

(Namespace(foo='bar', cmd='doit', rest=[1, 2, 3]), ['-n', '4'])
3.12.7 (main, Nov 16 2024, 20:18:07) [GCC 14.2.0]

[trevorld]

I've reported the bug to Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1087681

[aitap]

Apologies for not giving a better explanation on Debian BTS, but this is not only a Debian problem. The new ArgumentParser code in Debian Testing comes from the 3.12 branch of the official cpython repository and will become part of the next 3.12.x and 3.13.x tarballs. The change was a fix for python/cpython#125355. The test will break again on future released versions on Python.

[trevorld]

@aitap Thanks for the follow-up!