[R] S4 / operator "[" : Compatibility issue between lme4 and kml

[Martin Maechler]

>>>>> Martin Maechler <maechler at stat.math.ethz.ch>
>>>>>     on Fri, 5 Jun 2015 11:33:46 +0200 writes:

>>>>> Christophe Genolini <cgenolin at u-paris10.fr>
>>>>>     on Fri, 5 Jun 2015 00:36:42 -0700 writes:

    >> Hi all,
    >> There is a compatibility issue between the package 'lme4' and my package
    >> 'kml'. I define the "[" operator. It works just fine in my package (1). If I
    >> try to use the lme4 package, then it does no longer work (2). Moreover, it
    >> has some kind of strange behavior (3). Do you know what is wrong? Any idea
    >> of how I can correct that?

    >> Here is a reproductible example, and the same code with the result follows.

    > Dear Christophe,
    > can you please specify the exact sessionInfo() ?
    > (after loading both kml and lme4).

    > 'Matrix' has been updated on CRAN very recently, and 
    > 'lme4' is about to be update very soon,
    > so this *is* a somewhat interesting and important problem,
    > but the exact versions of the packages *do* matter.

As a matter of fact,  

1) the package versions don't seem to matter much.

2) lme4 is *not* involved directly:
   Much worse, it is the 'Matrix' package.

If you replace 'lme4' by 'Matrix' in your code, you get the same
symptoms.

... I'm investigating ..

Martin