[Rd] Error: package or namespace load failed for ‘utils

[Martin Maechler]

>>>>> Laurent Gautier 
>>>>>     on Sun, 15 Sep 2019 15:01:09 -0400 writes:

    > In case a search engine leads someone with the same issue
    > here, I am documenting the point I reached:

    > I can reproduce the issue with a small example when
    > forcing R to not load any package at startup time (using
    > an Renviron file): ``` package <- "utils" lib.loc <-
    > "<fill this according to your R install>" ns <-
    > loadNamespace(package, lib.loc) ```

    > The code path goes through
    > `registerS3methods(nsInfo$S3methods, package, env)` and
    > there to:

    > ``` if (methods::is(genfun, "genericFunction")) ```

    > The evaluation of `methods::is` reaches the line
    > triggering the error as `.identC(class1, class2)` and
    > `.identC(class2, "ANY")` both return `NA` and `NA || NA`
    > is not defined:

    > ```
    >> if (NA || NA) { cat("here\n") }
    > Error in if (NA || NA) { : missing value where TRUE/FALSE
    > needed ```

    > As I understand it `.identC()` should never return `NA`,

that understanding is correct, it should return TRUE or FALSE,
nothing else.

    > and if the case this would mean that R itself is an
    > unstable state (something at the C level that should not
    > have happened has happened) but this was not caught
    > earlier.

yes.. something like that...
My current diagnosis would be that something in your embedding of R happened
in a way that "broke R entirely" ...
but note that I know almost nothing about embedding R.

Martin