Next-date miscalculation for dates at the end of months followed by a shorter month

[brendonjwong]

I encountered a bug where dates at the end of months (e.g. March 30) that are followed by shorter months (in this case April) will get an incorrect next-date with the cron string "0 0 0 1 * *.

Examples:

(cronp/next-date (time/date-time 2020 3 30) "0 0 0 1 * *")

;; expected
#<org.joda.time.DateTime@1434863 2020-04-01T00:00:00.000Z>

;; actual
#<org.joda.time.DateTime@1434863 2020-03-31T00:00:00.000Z>

;; -------------------------------------------------------
(cronp/next-date (time/date-time 2020 1 30) "0 0 0 1 * *")

;; expected
#<org.joda.time.DateTime@4e6d20b 2020-02-01T00:00:00.000Z>

;; actual
#<org.joda.time.DateTime@4e6d20b 2020-01-30T00:00:00.000Z>

I've tracked the bug down to this line in the now-with-doms function: https://github.com/shmish111/clj-cron-parse/blob/b503a2dd96d6574fdc807947aacabd9c293b376d/src/clj_cron_parse/core.clj#L234