QDate::fromString() fails on certain dates

[jorge 0]

Qt 5.15, Qt 6.0, macOS 11.2 Big Sur. These conversions yield invalid dates:

qDebug() << QDate::fromString("1978-04-02",  "yyyy-MM-dd");
qDebug() << QDate::fromString("02-04-1978",  "dd-MM-yyyy");code_text

The following search yields four similar situations (1977-03-27, 1978-04-02, 1979-04-01,
1980-03-30):

   QString format("yyyy-MM-dd");
   for (int year=1930; year <= 2030; ++year)  {
      QDate date(year,1,1);
      while (date != QDate(year+1,1,1))   {
         QString str = date.toString(format);
         QDate converted = QDate::fromString(str, format);
         if (converted != date)
            qDebug() << date << converted;
         date = date.addDays(1);
      }
   }

Any ideas?

[Christian Ehrlicher]

Create a bug report about this. Works fine on linux.

[SGaist]

Hi and welcome to devnet,

Can you post the output you get ?

[jorge 0]

@SGaist the output is

QDate("1977-03-27") QDate(Invalid)
QDate("1978-04-02") QDate(Invalid)
QDate("1979-04-01") QDate(Invalid)
QDate("1980-03-30") QDate(Invalid)

Reported as a possible bug, as suggested (QTBUG-91120).