DateComponents.isValidDate() returns false if weekdayOrdinal is negative

Originator:ben
Number:rdar://34441094 Date Originated:9/14/17
Status:Open Resolved:
Product:Foundation Product Version:
Classification:Other bug Reproducible:Always
 
Summary: When working with calendar events there is sometimes a need to specify the last Monday/Wednesday/etc. of the month. My understanding is that this is achieved by setting the DateComponents.weekdayOrdinal to -1. However, while the date components consistently resolve to the correct date, calling dateComponents.isValidDate(calendar:) returns false when weekdayOrdinal = -1. 

For context, I'm running into this while working with EKRecurrenceRule.

Steps to Reproduce:
Please see the attached playground.

Expected Results:
I would expect it to return true when weekdayOrdinal is negative, as long as the date exists within that month, i.e. for values between -1 and -4/-5, depending on the month.

Actual Results:
isValidDate(calendar:) returns false when weekdayOrdinal = -1.

Version/Build:
Xcode 9 GM

Comments


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