[R-pkg-devel] Error in CHECK caused by dev.off()

Dear all,

I have two variables, foo and bar. The first is TRUE if a png should be 
created and the second is TRUE if an already existing one should be 
overwritten.
At the end of the plot I had
if (foo | (foo & bar)) dev.off()
This worked as expected in all versions of my package built in R up to 
v3.6.3. However, when I CHECK the package in v4.0.2 I get:
 > grDevices::dev.off()
Error in grDevices::dev.off() :
 ? cannot shut down device 1 (the null device)
Execution halted

I tried:
if (foo | (foo & bar)) {
 ? dev <- dev.list()
 ? if (!is.null(dev)) {
 ??? if (dev == 2) invisible(dev.off())
 ? }
}
without success (same error).

Even the more general
if (foo | (foo & bar)) {
 ? graphics.off()
}
did not work.

The plot is called only in an example of one man-page -- though embedded 
in \donttest{}.
Even if I set both foo and bar to FALSE (i.e., the respective part of 
the code should not be executed at all), I get the same error.

Any ideas/suggestions?

Regards,
Helmut

Ing. Helmut Sch?tz
BEBAC?? Consultancy Services for
Bioequivalence and Bioavailability Studies
Neubaugasse 36/11
1070 Vienna, Austria
W https://bebac.at/
F https://forum.bebac.at/