weirdness and probable bug with set xdata/ydata time

[Juhász P. <pet...@gm...>]

Hi,

I've ran into an issue with time data that looks like a bug.

The script below works as expected:

################
$data << END
2020-07-01      1.1
2020-07-08      2.2
2020-07-15      3.3
END

set xdata time
set timefmt "%Y-%m-%d"
#set ydata time
plot $data u 1:2 w lp
###############

It produces a plot with correctly parsed and displayed dates on the x
axis, and the x range is also sensible.

But uncomment the `set ydata time` line and it fails:

################
         "x.plt" line 10: warning: Skipping data file with no valid
points

gnuplot> plot $data u 1:2 w lp
                              ^
         "x.plt" line 10: x range is invalid
##############

I can sort of understand that it fails because it can't parse the
second column as date - but then why does it report the *x* range as
invalid?

Even more spooky is what it thinks about the x range after the failed
plot:
##############
gnuplot> sh xr

	set xdata time
	set xrange [ * : * ] noreverse writeback  # (currently
["         warning: time value out of range
0000-35-32586":"         warning: time value out of range
0000-35-32586"] )
#############

If I run gnuplot with valgrind, it barfs some "Conditional jump or move
depends on uninitialised value(s)" errors, so some internal state is
definitely corrupted.

Best regards,
Peter Juhasz