[Rd] paste(character(0), collapse="", recycle0=FALSE) should be ""

[Martin Maechler]

>>>>> Martin Maechler 
>>>>>     on Wed, 27 May 2020 13:35:44 +0200 writes:

>>>>> Hervé Pagès 
>>>>>     on Tue, 26 May 2020 12:38:13 -0700 writes:

    >> Hi Martin, On 5/26/20 06:24, Martin Maechler wrote: ...
    >>> 
    >>> What about remaining back-compatible, not only to R 3.y.z
    >>> with default recycle0=FALSE, but also to R 4.0.0 with
    >>> recycle0=TRUE

    >> What back-compatibility with R 4.0.0 are we talking about?
    >> The 'recycle0' arg was added **after** the R 4.0.0 release
    >> and has never been part of an official release yet. 

    > Yes, of course.  It was *planned* for R 4.0.0 and finally was
    > too late (feature freeze etc)... I'm sorry I was wrong and
    > misleading above.

    >> This is the time to fix it.

    > Well, R 4.0.1 is already in 'beta' and does contain it too.
    > So the "fix" should happen really really fast, or we (R core)
    > take it out from there entirely.

Well, in the end your repeated good reasoning has prevailed:
I've committed a change (to R-devel; most probably in
time to be ported to 4.0.1 beta).
I think this implements the   recycle0 = TRUE   behavior you
have been advocating for, 
in svn r78591  (2020-05-27 19:45:07 +0200)   with message

     paste(), paste0(): collapse=<string> always gives a string
     (also w/ `recycle0=TRUE`)

Best regards,
Martin