* Corrected date time detection
German and Swiss ZIP codes (special formats provided in German Excel versions) were detected as date time value, because the regular expression for date time formats falsely matched their formats ("\C\H\-00000" and "\D-00000").
* Fix Issue 1441 (isDateTime and Formulas)
When you have a date-field which is a formula, isDateTime returns false.
https://github.com/PHPOffice/PhpSpreadsheet/issues/1441
Report makes sense; fixed as suggested. Also fixed a few minor
related issues, and added tests so that Shared/Date and Shared/TimeZone
are now completely covered.
Date/setDefaultTimeZone and TimeZone/setTimeZone were not consistent
about what to do in event of failure - return false or throw.
They will now both return false, which is what Date's function
said it would do in its doc block anyhow. Date/validateTimeZone will
continue to throw; it was protected, but was never called outside
Date, so I changed it to private.
TimeZone/getTimeZoneAdjustment checked for 'UST' when it probably
meant 'UTC', and, as it turns out, the check is not even needed.
The most serious problem was that TimeZone/validateTimeZone does not
check the backwards-compatible time zones. The timezone project
aggressively, and very controversially, "demotes" timezones;
such timezones eventually wind up in the PHP backwards-compatible list.
We want to make sure to check that list so that our applications do not
break when this happens.
Christoph Ziegenberg