Bug #74511 [Nab]: Cannot construct a \DateTime from a valid format ("Y-\WW")

Edit report at https://bugs.php.net/bug.php?id=74511&edit=1 ID: 74511 Updated by: heiglandreas@php.net Reported by: jack dot peterson at gmail dot com Summary: Cannot construct a \DateTime from a valid format ("Y-\WW") Status: Not a bug Type: Bug Package: Date/time related Operating System: Ubuntu 16.04 PHP Version: 7.1.4 Block user comment: N Private report: N New Comment: The formats documented for 'date' are output formats, not input formats. Accepted formats for DateTime::createFromFormat are explained at http://php.net/manual/de/datetime.createfromformat.php - I can not find a "W" in there. Even if it would be given there, what date would you expect it to return? First Day of the week? Last Day of the Week? What is the first day of the week? Sunday? Monday? And why exactly "should (one) be able to construct a date" with that? What exactly is your use case for that? Previous Comments: ------------------------------------------------------------------------ [2017-04-28 17:53:48] requinix@php.net DateTime represents an actual date. What date would 2017-W01 represent? ------------------------------------------------------------------------ [2017-04-28 17:49:53] jack dot peterson at gmail dot com Description: ------------ Given the format, 'Y-\WW', one should be able to construct a date such as 2017-W01 or 2017-W1 as a valid date where W is a number from 0-52 as documented for Date. The expected behavior here would be to create a valid date w/ the next least-significant values to be zeroed out. Current behavior is that one cannot construct a valid \DateTime from the requested format. Test script: --------------- public function testCanCreateDateFromFormat() { $format = 'Y-\WW'; $date = '2017-W01'; $obj = \DateTime::createFromFormat($format, $date); $this->assertInstanceOf(\DateTime::class, $obj); } testCanCreateDateFromFormat Failed asserting that false is an instance of class "DateTime". Expected result: ---------------- \DateTime::createFromFormat should return an instance of \DateTime Actual result: -------------- \DateTime::createFromFormat returns false in this scenario. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=74511&edit=1