[Rd] Possible bug when finding shared libraries during staged installation

[Martin Maechler]

>>>>> Kara Woo 
>>>>>     on Thu, 23 May 2019 14:24:26 -0700 writes:

    > Hi all,
    > With the new staged installation, it seems that R CMD INSTALL sometimes
    > fails on macOS due to these lines [1] when sapply() returns a list. The
    > x13binary package has an example [2], reproducible with the following steps:

    > $ git clone git using github.com:x13org/x13binary.git && cd x13binary
    > $ git checkout 663ad7122
    > $ R CMD INSTALL .

    > (We've also run into it in an internal package, but it's easier to
    > reproduce with x13binary)

    > In this case the file command returns multiple results for one of the
    > dynamic libraries, so are_shared looks like this:

    >> are_shared
    > $`/Users/Kara/projects/forks/x13binary/inst//lib/libgcc_s.1.dylib`
    > [1] TRUE TRUE TRUE

    > $`/Users/Kara/projects/forks/x13binary/inst//lib/libgfortran.3.dylib`
    > [1] TRUE

    > $`/Users/Kara/projects/forks/x13binary/inst//lib/libquadmath.0.dylib`
    > [1] TRUE

Thank you, Kara.

Just for curiosity, what does

 file /Users/Kara/projects/forks/x13binary/inst//lib/libgcc_s.1.dylib

produce on your Mac?

    > slibs[are_shared] then fails with invalid subscript type 'list'.

yes, "of course".

    > I believe this may be a bug and I have included a patch that uses any() and
    > vapply() to ensure that only one value is returned for each library and the
    > result is an atomic vector. This is my first time submitting a bug report
    > or patch here; I'm happy to make any changes if needed.

Your patch was not attached with MIME type   text/plain  and so
was filtered out by the mailing list software.
OTOH, I could relatively easily guess how to fix the bug,
notably when seeing the above "file ...dylib" result.

What we *meant* to say in  https://www.r-project.org/bugs.html 
is that in such a situation
1) you send your finding / suspicion / diagnosis
   to the R-devel mailing list,  in order to get confirmation etc
   if what you see is a bug;
2) then ideally, you'd do a formal bug report at
   https://bugs.r-project.org/
	(for which you need to get an "account" there to be created
	 once only by a bugzilla admin, typically an R core member).

In this case, that (2) may not be necessary, but you may want
that anyway (and let some of us know).

    > Thanks for considering,
    > Kara

Thank *you* indeed for the report,
Martin

    > [1]
    > https://github.com/wch/r-source/blob/3fe2bb01e9ec1b268803a437c308742775c2442d/src/library/tools/R/install.R#L594-L597
    > [2] https://github.com/x13org/x13binary/issues/46

    > R version 3.6.0 Patched (2019-05-22 r76579)
    > Platform: x86_64-apple-darwin15.6.0 (64-bit)
    > Running under: macOS Mojave 10.14.4

--
Martin Maechler
ETH Zurich  and  R Core Team