Says why a fedSubjectPattern may not be used: too long, a backreference, a
quantified group that is itself quantified or an alternation, or a pattern
that does not compile.
Parameters
text: any
the pattern
Returns string
the problem, or the empty string when it is usable or empty
Says why a
fedSubjectPatternmay not be used: too long, a backreference, a quantified group that is itself quantified or an alternation, or a pattern that does not compile.