protected final DateTimeFormatter CHRONO_FORMAT = new
DateTimeFormatterBuilder()
     .optionalStart()
     .appendChronologyId()
     .appendLiteral(' ')
     .optionalEnd()
     .optionalStart()
     .appendText(ChronoField.ERA, TextStyle.FULL) // FAILS HERE
     .appendLiteral(' ')
     .optionalEnd()
     .appendValue(ChronoField.YEAR_OF_ERA, 1, 9, SignStyle.NORMAL)
     .appendLiteral('-')
     .appendValue(ChronoField.MONTH_OF_YEAR, 1, 2, SignStyle.NEVER)
     .appendLiteral('-')
     .appendValue(ChronoField.DAY_OF_MONTH, 1, 2, SignStyle.NEVER)
     .toFormatter();

will parse HijrahDate and JapaneseDate toString values, but not MinguoDate
or ThaiBuddhistDate. It fails when trying to parse the era. I've also tried
TextStyle.Short, appendPattern("G") and appendPattern("GGGG"). All fail in
exactly the same place.

   CHRONO_FORMAT.parse(HijrahDate.of(1970, 02, 03).toString());
   CHRONO_FORMAT.parse(JapaneseDate.of(1970, 02, 03).toString())
   CHRONO_FORMAT.parse(MinguoDate.of(1970, 02, 03).toString());
   CHRONO_FORMAT.parse(ThaiBuddhistDate.of(1970, 02, 03).toString());