[Rcpp-devel] Any recent change that would remove Rcpp_precious_remove?

[Dominick Samperi]

Hello Dirk,

I have what appears to be a reproducible example of the
"Rcpp_precious_remove"
problem that a few people have complained about. It is reproducible on my
Mac Mini, but may not appear when you try because it is OS and compiler
dependent. There is no problem under Windows, for example. There
seems to be a gc bug lurking.

The test C++ source file (a simple REPL loop), makefile, and
lldb (debugger) backtrace are attached to this message.
When I compile and run on my Mac it fails with a seg fault.

This was tested using R 4.1.1, Rcpp 1.0.7, RInside 0.2.16,
MacOS 10.15.7, and Apple clang 12.0.0.

I have been able to trigger this problem under Ubuntu in
a more complicated project using CMake. It fails every time.
Furthermore, gdb shows that the failure happens on
line 261 of RInside.cpp (where global_env_m = new Rcpp::Environment()).

The comment immediately above this failure point says
there is exposure to "a minimal risk of garbage collection" (based on
feedback from Doug Bates and Luke Tierney). Perhaps the risk is greater
than you anticipated?

BTW, if I build the REPL app and link to a locally built version of
RInside library, and not to the version installed by R, the REPL
app works on my Mac Mini! This is probably due to the fact
that stack/heap corruption can reveal itself in mysterious ways
depending on the precise configuration employed.

Thanks,
Dominick

On Thu, Jul 15, 2021 at 8:13 AM Dirk Eddelbuettel <edd at debian.org> wrote:

>
> On 15 July 2021 at 08:24, ma wh wrote:
> | Colleague of mine wrote some R last week that was working OK, and hasn't
> been changed in itself since that time. This week it's ceased working( I've
> tried it on my machine and also see a fail, the following error is
> encountered:
> |
> | Error in C_valid_tz(tzone): Function 'Rcpp_precious_remove' not provided
> by package 'Rcpp'
> |
> | Searching around there aren't many hits. Those I do find seem quite
> recent (stackoverflow questions or GitHub issues logged in various
> projects, dates of posting are within the last few days). None of the
> posted queries seem to have a solution, one person said restarting RStudio
> helped, but not in my case. The SO question I found was marked as deleted.
> The GitHub issue I found was "I solved it" but no mention of how. The SO
> question was asking about svg export:
> https://stackoverflow.com/questions/68345118/exporting-a-ggplot-in-svg-call-a-non-esixting-function
> | The GitHub were also asking about packages I don't use -
> | https://github.com/r-spatial/spdep/issues/60
> | https://github.com/drizopoulos/JMbayes2/issues/5
> |
> | Anyone on the list have any pointers? Thanks
>
> Packages following a the GNU style often have a file ChangeLog which
> "details
> changes made to the code". Rcpp follows this convention, see 2021-07-05 and
> 2021-01-017.
>
> Packages following the R packaging conventions often have a file
> inst/NEWS.rd
> (also rendered as NEWS at CRAN). Rcpp follow this conventions, see the Rcpp
> 1.0.7 release (even if the functions is not named).
>
> Packages have source code you can search.I like `ag` aka "the
> silversearcher":
>
>   edd at rob:~/git/rcpp(master)$ ag -c Rcpp_precious_remove
>   ChangeLog:2
>   inst/include/Rcpp/routines.h:3
>   inst/include/RcppCommon.h:2
>   src/rcpp_init.cpp:1
>   src/barrier.cpp:1
>   edd at rob:~/git/rcpp(master)$
>
> It is still there, and available via the standard export mechanism.
>
> I recommend your friend take a look. The function is a) still there yet has
> also b) been supplanted by a more sufficient alternative.
>
> Otherwise, a reproducible example would be the only way to make this
> concrete.
>
> Hope this helps, Dirk
>
> --
> https://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org
> _______________________________________________
> Rcpp-devel mailing list
> Rcpp-devel at lists.r-forge.r-project.org
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(lldb) bt
* thread #1, queue = com.apple.main-thread, stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
  * frame #0: 0x000000010647ee99 Rcpp.so`Rcpp::Rcpp_precious_remove(token=0x0000000000000000) at barrier.cpp:[opt]
    frame #1: 0x0000000100003467 repl`Rcpp::Rcpp_precious_remove(SEXPREC*) + 119
    frame #2: 0x00000001000033e5 repl`Rcpp::Rcpp_PreciousRelease(SEXPREC*) + 21
    frame #3: 0x00000001000033ad repl`Rcpp::PreserveStorage<Rcpp::RObject_Impl<Rcpp::PreserveStorage> >::~PreserveStorage() + 29
    frame #4: 0x0000000100003388 repl`Rcpp::RObject_Impl<Rcpp::PreserveStorage>::~RObject_Impl() + 24
    frame #5: 0x0000000100003365 repl`Rcpp::RObject_Impl<Rcpp::PreserveStorage>::~RObject_Impl() + 21
    frame #6: 0x0000000100003345 repl`RInside::Proxy::~Proxy() + 21
    frame #7: 0x0000000100002fd5 repl`RInside::Proxy::~Proxy() + 21
    frame #8: 0x0000000100002e77 repl`main + 183
    frame #9: 0x00007fff7260bcc9 libdyld.dylib`start + 1
(lldb) exit
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