[Rd] [External] Something is wrong with the unserialize function

[iuke-tier@ey m@iii@g oii uiow@@edu]

I found that also; fixed in r79386 in the trunk. Will port to R-patched
shortly.

Best,

luke

On Thu, 29 Oct 2020, Martin Morgan wrote:

> This
>
> Index: src/main/altrep.c
> ===================================================================
> --- src/main/altrep.c	(revision 79385)
> +++ src/main/altrep.c	(working copy)
> @@ -275,10 +275,11 @@
> 	SEXP psym = ALTREP_SERIALIZED_CLASS_PKGSYM(info);
> 	SEXP class = LookupClass(csym, psym);
> 	if (class == NULL) {
> -	    SEXP pname = ScalarString(PRINTNAME(psym));
> +	    SEXP pname = PROTECT(ScalarString(PRINTNAME(psym)));
> 	    R_tryCatchError(find_namespace, pname,
> 			    handle_namespace_error, NULL);
> 	    class = LookupClass(csym, psym);
> +	    UNPROTECT(1);
> 	}
> 	return class;
>     }
>
> seems to remove the warning; I'm guessing that the other SEXP already exist so don't need protecting?
>
> Martin Morgan
>
>
> On 10/29/20, 12:47 PM, "R-devel on behalf of luke-tierney using uiowa.edu" <r-devel-bounces using r-project.org on behalf of luke-tierney using uiowa.edu> wrote:
>
>    Thanks for the report. Will look into it when I get a chance unless
>    someone else gets there first.
>
>    A simpler reprex:
>
>    ## create and serialize a memmory-mapped file object
>    filePath <- "x.dat"
>    con <- file(filePath, "wrb")
>    writeBin(rep(0.0,10),con)
>    close(con)
>
>    library(simplemmap)
>    x <- mmap(filePath, "double")
>    saveRDS(x, file = "x.Rds")
>
>    ## in a separate R process:
>    gctorture()
>    readRDS("x.Rds")
>
>    Looks like a missing PROTECT somewhere.
>
>    Best,
>
>    luke
>
>    On Thu, 29 Oct 2020, Jiefei Wang wrote:
>
>    > Hi all,
>    >
>    > I am not able to export an ALTREP object when `gctorture` is on in the
>    > worker. The package simplemmap can be used to reproduce the problem. See
>    > the example below
>    > ```
>    > ## Create a temporary file
>    > filePath <- tempfile()
>    > con <- file(filePath, "wrb")
>    > writeBin(rep(0.0,10),con)
>    > close(con)
>    >
>    > library(simplemmap)
>    > library(parallel)
>    > cl <- makeCluster(1)
>    > x <- mmap(filePath, "double")
>    > ## Turn gctorture on
>    > clusterEvalQ(cl, gctorture())
>    > clusterExport(cl, "x")
>    > ## x is an 0-length vector on the worker
>    > clusterEvalQ(cl, x)
>    > stopCluster(cl)
>    > ```
>    >
>    > you can find more info on the problem if you manually build a connection
>    > between two R processes and export the ALTREP object. See output below
>    > ```
>    >> con <- socketConnection(port = 1234,server = FALSE)
>    >> gctorture()
>    >> x <- unserialize(con)
>    > Warning message:
>    > In unserialize(con) :
>    >  cannot unserialize ALTVEC object of class 'mmap_real' from package
>    > 'simplemmap'; returning length zero vector
>    > ```
>    > It seems like  simplemmap did not get loaded correctly on the worker. If
>    > you run `library( simplemmap)` before unserializing the ALTREP, there will
>    > be no problem. But I suppose we should be able to unserialize objects
>    > without preloading the library?
>    >
>    > This issue can be reproduced on Ubuntu with R version 4.0.2 (2020-06-22)
>    > and Windows with R Under development (unstable) (2020-09-03 r79126).
>    >
>    > Here is the link to simplemmap:
>    > https://github.com/ALTREP-examples/Rpkg-simplemmap
>    >
>    > Best,
>    > Jiefei
>    >
>    > 	[[alternative HTML version deleted]]
>    >
>    > ______________________________________________
>    > R-devel using r-project.org mailing list
>    > https://stat.ethz.ch/mailman/listinfo/r-devel
>    >
>
>    --
>    Luke Tierney
>    Ralph E. Wareham Professor of Mathematical Sciences
>    University of Iowa                  Phone:             319-335-3386
>    Department of Statistics and        Fax:               319-335-3017
>        Actuarial Science
>    241 Schaeffer Hall                  email:   luke-tierney using uiowa.edu
>    Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu
>
>    ______________________________________________
>    R-devel using r-project.org mailing list
>    https://stat.ethz.ch/mailman/listinfo/r-devel
>

-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:   luke-tierney using uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu