Dear R friends,
to allow post-mortem debugging In my Rscript based batch jobs I use
tryCatch( <R expression>,
error = function(e)
{
dump.frames(to.file = TRUE)
})
to write the called frames into a dump file.
This is similar to the method recommended in the "Writing R extensions"
manual in section 4.2 Debugging R code (page 96):
https://cran.r-project.org/doc/manuals/R-exts.pdf
> options(error = quote({dump.frames(to.file=TRUE); q()}))
When I load the dump later in a new R session to examine the error I use
load(file = "last.dump.rda")
debugger(last.dump)
My problem is that the global objects in the workspace are NOT contained
in the dump since "dump.frames" does not save the workspace.
This makes debugging difficult.
For more details see the stackoverflow question + answer in:
https://stackoverflow.com/questions/40421552/r-how-make-dump-frames-include-all-variables-for-later-post-mortem-debugging/40431711#40431711
I think the reason of the problem is:
------------------------------------
If you use dump.files(to.file = FALSE) in an interactive session
debugging works as expected because it creates a global variable called
"last.dump" and the workspace is still loaded.
In the batch job scenario however the workspace is NOT saved in the dump
and therefore lost if you debug the dump in a new session.
Options to solve the issue:
--------------------------
1. Improve the documentation of the R help for "dump.frames" and the
R_exts manual to propose another code snippet for batch
job scenarios:
dump.frames()
save.image(file = "last.dump.rda")
2. Change the semantics of "dump.frames(to.file = TRUE)" to include
the workspace in the dump.
This would change the semantics implied by the function name
but makes the semantics consistent for both "to.file" param values.
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
