Scope of changes:

https://docs.mongodb.com/manual/reference/operator/aggregation/dateFromParts/index.html should be updated to indicate that month, day, etc can be higher or lower than previous limits and correct date will be calculated.

Also example can/should be added showing how to get last day of previous month or year (using 0 day) or how subtracting allows calculating via date intervals.

Impact to other docs outside of this product:

none

MVP:

Resources:

Engineering Ticket Description:

Currently $dateFromParts will handle appropriately a day that's bigger than largest day in the specified month (i.e. year:2017, month:2, day:30 correctly becomes "2017-03-02" since there are only 28 days in February) but if day is >31 it gives an error. Same for month>12.

”‘day’ must evaluate to an integer in the range 1 to 31, found 32"

Instead it should just construct appropriate date (so 2017, 2, 32 is "2017-03-03" and 2017 month 13 is January of 2018. This allows simple construction of dates that are X days after given date or Y months after given date, etc.