[Rd] failed check in reg-tests-1b.R

[Martin Maechler]

>>>>> Benjamin Tyner 
>>>>>     on Tue, 19 May 2020 22:36:16 -0400 writes:

    > Not certain this is actually a bug, so posting here.
    > I'm on Ubuntu 18.04.4 LTS, building R version 4.0.0. The "configure" and 
    > "make" steps are successful, but the "make check" step fails when it 
    > gets to this part of ./tests/reg-tests-1b.R:

    >    > ## methods() gave two wrong warnings in some cases:
    >    > op <- options(warn = 2)# no warning, please!
    >    > m1 <- methods(na.omit) ## should give (no warning):
    >    > ##
    >    > setClass("bla")
    >    > setMethod("na.omit", "bla", function(object, ...) "na.omit(<bla>)")
    >    Error: package 'codetools' was installed before R 4.0.0: please 
    > re-install it
    >    Execution halted

    > It appears to be picking up the older version of codetools from $R_LIBS; 
    > if I unset R_LIBS, then it works just fine.

    > So I'm wondering, is it a bug, or is the user's own fault for having 
    > R_LIBS set whilst trying to build R?

Well, currently it seems to be the user's fault as in
      "if you don't do it, everything is fine"

But it has bitten me too, many times actually,
when going from R 3.y.z to R 4.y.z .
I have not started to investigate what it would mean, or even
if it really makes sense to disregard R_LIBS in such situations.

For building (and checking!) R itself from the sources, it may
seem to make sense indeed if such environment variables would be
temporarily unset (by one of the Makefiles, say).

Martin