nul byte returned

[daroczig]

Hi @jeroen,

First of all -- as always, thanks a lot for this fantastic package!

I've run into an issue when using eval_fork to return an SVG object (please find attached):

> library(unix)
> x <- readRDS('svg')

> str(x)
 chr "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<svg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3."| __truncated__

> str(eval_fork(x))
Error in eval_fork_internal(expr = clexpr, envir = clenv, tmp = tmp, timeout = timeout,  : 
  embedded nul in string: '<?xml version="1.0" encoding="UTF-8"?>\n<svg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' id='svg_e1ac679b-b9c0-4635-85ef-0895857227fe' viewBox='0 0 630.00 360.00'>\n  <g>\n    <defs>\n      <clipPath id='svg_e1ac679b-b9c0-4635-85ef-0895857227fe_cl_1'>\n        <rect x='0.00' y='0.00' width='630.00' height='360.00'/>\n      </clipPath>\n    </defs>\n    <rect x='0.00' y='0.00' width='630.00' height='360.00' id='svg_e1ac679b-b9c0-4635-85ef-0895857227fe_el_1' clip-path='url(#svg_e1ac679b-b9c0-4635-85ef-0895857227fe_cl_1)' fill='#FFFFFF' fill-opacity='1' stroke='#FFFFFF' stroke-opacity='1' stroke-width='0.75' stroke-linejoin='round' stroke-linecap='round'/>\n    <defs>\n      <clipPath id='svg_e1ac679b-b9c0-4635-85ef-0895857227fe_cl_2'>\n        <rect x='0.00' y='0.00' width='630.00' height='360.00'/>\n      </clipPath>\n    </defs>\n    <rect x='0.00' y='0.00' width='630.00' height='360.00' id='svg_e1ac679b-b9c0-4635-85e

Session info

> sessionInfo()
R version 4.0.2 (2020-06-22)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Debian GNU/Linux bullseye/sid

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3
LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.13.so

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] unix_1.5.1

loaded via a namespace (and not attached):
[1] compiler_4.0.2 tools_4.0.2   

Example file: svg.zip (EDIT: deleted, as better minimal, reproducible examples shared below)

Any ideas where the serialization might go wrong?

[jeroen]

Hmm this seems to work:

eval_safe(x)

Maybe the problem is that the expression gets substituted for a very long inline string whichs hits some limit on the size of the R call/expression.

Here is a minimal example:

library(unix)
x <- strrep("a", 65000)
y <- strrep("a", 66000)
x2 <- eval_fork(x)
y2 <- eval_fork(y)

[daroczig]

Ah, right - hitting 2^16 characters results in this error 👍

> eval_fork(paste(rep('a', 2^16 + 1), collapse = ''))
Error in eval_fork_internal(expr = clexpr, envir = clenv, tmp = tmp, timeout = timeout,  : 
  embedded nul in string: 

Let me debug further my original issue and come up with a better minimal example, as it's actually a pretty long and complex list.

[daroczig]

Hm, I did not manage to get your eval_fork + list example working:

> library(unix)
> y <- strrep("a", 66000)
> eval_fork(list(x = y))
Error in eval_fork_internal(expr = clexpr, envir = clenv, tmp = tmp, timeout = timeout,  : 
  embedded nul in string

Anyway, I guess I should stick with eval_safe where serialization doesn't seem to be an issue. Feel free to close the ticket, and thanks a lot again.

[jeroen]

You are right. I won't close the issue just yet I'd like to understand it better first.