Do not use "guru" as debug level.
See this code from gnupg:
else if (!strcmp (level, "guru") || numok)
{
opt.debug = ~0;
/* Unless the "guru" string has been used we don't want to allow
hashing debugging. The rationale is that people tend to
select the highest debug value and would then clutter their
disk with debug files which may reveal confidential data. */
if (numok)
opt.debug &= ~(DBG_HASHING_VALUE);
}