[R] Error when calling (R 4.0.x on Windows) from Python

[Duncan Murdoch]

On 27/01/2021 3:38 a.m., Martin Maechler wrote:
>>>>>> Martin Maechler
>>>>>>      on Tue, 26 Jan 2021 12:37:58 +0100 writes:
> 
>>>>>> Marcel Baumgartner
>>>>>>      on Tue, 26 Jan 2021 08:55:48 +0100 writes:
> 
>      >> Dear all, my colleague posted our issue on stackoverflow:
> 
>      >> Calling R script from Python does not save log file in
>      >> version 4 - Stack Overflow
>      >> [https://stackoverflow.com/questions/65887485/calling-r-script-from-python-does-not-save-log-file-in-version-4]
> 
>      >> It is about this kind of call to R:
> 
>      >> R.exe -f code.R --args "~/file.txt" 1> "~/log.txt" 2>&1".
> 
>      >> The issue is that the log.txt file is not created when
>      >> running R 4.x.x. The same code works perfectly fine with
>      >> R 3.6.x.
> 
>      >> Any idea what's going wrong as of version 4? Regards
>      >> Marcel
> 
>      > Dear Marcel, I think the solution is embarrassingly
>      > simple:
> 
>      >> From the SO post, where she showed a bit more detail than you
>      > show here, it's clear you have confused 'R.exe' and
>      > 'Rscript.exe' and what you say above is not true:
> 
>      > 'R.exe' was used for R 3.6.0 but for R 4.0.3, you/she used
>      > 'Rscript.exe' instead.
> 
> 
>      > ... as you've noticed now, they do behave differently,
>      > indeed!
> 
> Well, this was not the solution to their -- Windows-only -- problem.
> The problem *is* indeed visible if they only use  R.exe  (also
> for R 4.0.3).
> 
> I've commented more on the SO issue (see above),
> notably asking for a *minimal* repr.ex. (reproducible example),
> and one *not* using "<YOUR PATH>" and setwd() ..
> 

Isn't this purely a Python or user problem?  R shouldn't process 
redirection directives like

   1> "~/log.txt" 2>&1

because it's the shell's job to process those. If Python is acting as 
the shell, it needs to handle those things.  If R was handling the 
command via

Duncan Murdoch