[Rd] Large number of linked environments makes save() crash R

[Henrik Bengtsson (max 7Mb)]

Hi,

first, this not a problem originating from me, but it was observed
trying to do similar things with my R.oo package, so I troubleshooted
it and found the following.

On R v2.3.0 (patched), the following will crash R on WinXP sooner or later:

troubleLimit <- 20435;

linkedList <- list(head=new.env());

currEnv <- linkedList$head;
for (kk in 1:(2*troubleLimit)) {
  if (kk %% 100 == 0)
    print(kk);
  nextEnv <- new.env();
  assign("nxt", nextEnv, envir=currEnv);
  currEnv <- nextEnv;
  if (kk > troubleLimit) {
    cat("Saving linked list of length ", kk, "...", sep="");
    save(linkedList, file="linkedList.RData");
    cat("ok\n");
  }
}

This gives:
...
[1] 20300
[1] 20400
Saving linked list of length 20436...ok
Saving linked list of length 20437...ok
Saving linked list of length 20438...

and then R crashes/terminates.  On my WinXP machine it always happens
at the same number of environments.

I tried the same on R v2.2.0 (sic!) on Unix and there it gave a
segfault a bit after 10000 environments.  ...and, the purpose of the
example is not to implement linked lists, it to show that you can
torture R to crash.

Cheers

Henrik

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