Weekly Rule with selected Weekdays does not produce the correct dates.

[ccc-dbellinger]

Hello,

When using a weekly frequency with a BYDAY rule, only days between the weekday of DTSTART and the day before WKST (inclusive) are considered. See the following example:

<?php

use RRule\RRule;

include 'vendor/autoload.php';

$dtstart = DateTimeImmutable::createFromFormat('Y-m-d H:i', '2021-01-08 08:00');
$parts = [
    'BYDAY' => [ 'MO', 'WE', 'FR' ],
    'FREQ' => 'WEEKLY',
    'WKST' => 'SU',
    'DTSTART' => $dtstart,
];
$rrule = new RRule($parts);

$start = DateTimeImmutable::createFromFormat('Y-m-d', '2020-01-01');
$end = DateTimeImmutable::createFromFormat('Y-m-d', '2021-12-31');

$occurrences = $rrule->getOccurrencesBetween($start, $end, 10);

foreach ($occurrences as $occurrence) {
    echo $occurrence->format('l, F j, Y H:i T') . "\n";
}

This produces the following output:

Friday, January 8, 2021 08:00 EST
Friday, January 15, 2021 08:00 EST
Friday, January 22, 2021 08:00 EST
Friday, January 29, 2021 08:00 EST
Friday, February 5, 2021 08:00 EST
Friday, February 12, 2021 08:00 EST
Friday, February 19, 2021 08:00 EST
Friday, February 26, 2021 08:00 EST
Friday, March 5, 2021 08:00 EST
Friday, March 12, 2021 08:00 EST

I believe this should include Mondays and Wednesdays after the first week, Thus it should be the following output:

Friday, January 8, 2021 08:00 EST
Monday, January 11, 2021 08:00 EST
Wednesday, January 13, 2021 08:00 EST
Friday, January 15, 2021 08:00 EST
Monday, January 18, 2021 08:00 EST
Wednesday, January 20, 2021 08:00 EST
Friday, January 22, 2021 08:00 EST
Monday, January 25, 2021 08:00 EST
Wednesday, January 27 2021 08:00 EST
Friday, January 29, 2021 08:00 EST

Changing the above DTSTART value to 2021-01-04 08:00 produces the correct dates:

Monday, January 4, 2021 08:00 EST
Wednesday, January 6, 2021 08:00 EST
Friday, January 8, 2021 08:00 EST
Monday, January 11, 2021 08:00 EST
Wednesday, January 13, 2021 08:00 EST
Friday, January 15, 2021 08:00 EST
Monday, January 18, 2021 08:00 EST
Wednesday, January 20, 2021 08:00 EST
Friday, January 22, 2021 08:00 EST
Monday, January 25, 2021 08:00 EST

[pluk77]

After a quick test it seems that this happens when DTSTART is an Immutable DateTime object. Change it to:

$dtstart = DateTime::createFromFormat('Y-m-d H:i', '2021-01-08 08:00');

returned the expected 10 dates.

[pluk77]

I suppose the parseDate function should either throw an exception if an immutable DateTime is used, or it should not directly clone the object but rather convert it to a mutable DateTime object?

[pluk77]

something like this:

static public function parseDate($date)
{
    if (!$date instanceof \DateTime) {
        try {
            if (is_integer($date)) {
                $date = \DateTime::createFromFormat('U', $date);
                $date->setTimezone(new \DateTimeZone('UTC')); // default is +00:00 (see issue #15)
            } elseif ($date instanceof \DateTimeImmutable) {
                if (method_exists(\DateTime::class, 'createFromImmutable')) {
                    $date = \DateTime::createFromImmutable($date);
                } else {
                    $date = new \DateTime($date->format(\DateTime::ATOM));
                }
            } else {
                $date = new \DateTime($date);
            }
        } catch (\Exception $e) { // PHP 5.6
            throw new \InvalidArgumentException(
                    "Failed to parse the date ({$e->getMessage()})"
            );
        } catch (\Throwable $e) { // PHP 7+
            throw new \InvalidArgumentException(
                    "Failed to parse the date ({$e->getMessage()})"
            );
        }
    } else {
        $date = clone $date; // avoid reference problems
    }
    return $date;
}

[rlanvin]

The fix is available in v2.2.1, thanks for the bug report!