From: "kei-p (Keisuke Ishizawa)" <noreply@...>
Date: 2022-07-29T08:26:54+00:00
Subject: [ruby-dev:51187] [Ruby master Bug#18946] Time#to_date returns incorrect date

Issue #18946 has been updated by kei-p (Keisuke Ishizawa).


> Time seems to use a proleptic Gregorian calendar (the Gregorian calendar extended to before the Gregorian reform, see https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar) while Date seems to be using the Julian calendar before the 'official' reform date. 

Thanks for the detailed explanation.
I understand that this is due to the different calendars that Date and Time uses before the 'official' reform date.

----------------------------------------
Bug #18946: Time#to_date returns incorrect date
https://bugs.ruby-lang.org/issues/18946#change-98505

* Author: kei-p (Keisuke Ishizawa)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.2
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Time#to_date returns incorrect date.

Actual Behavior:
```
Time.local(1499, 12, 27).to_date
=> #<Date: 1499-12-18 ((2268919j,0s,0n),+0s,2299161j)>
```

Expected Behavior:
```
Time.local(1499, 12, 27).to_date
=> #<Date: 1499-12-27 ...>
```



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