Min/max date inputs error badly if you input an invalid date

[hickman-santini]

Current behavior

Following up on #742 (comment)

If both min/max datetimes are touched, and one's briefly invalid, it crashes:
(Reproduction: flip AM/PM on min or max, then change the other month to 11)

(You get an "Error: Try again" page and lose your work)

Unintuitive to remember to not input leading zeroes and edit days before months because ~half the months don't have the default (31st)

Happens consistently on Chrome on Mac. Better luck with how <input type="datetime-local"> works on mobile

While we're at it:

https://www.metaculus.com/questions/create/question/?type=date defaults seem better than
https://www.metaculus.com/questions/create/group/?subtype=date defaulting min and max to the epoch

@ncarazon can you just remove the epoch defaults from group date question creation?

[SylvainChevalier]

Duplicate of #1371, copying here for consolidation:

If I press 0 here

I get this

I assume because the creator is trying to make a graph with an invalid date. I know I don't need to press 0 for anything (I can just do 1 for 01), but if I forget and press it I lose all of my progress on the question.

tbc, to reproduce:

• create date qestion
• enter valid min and max dates
• the pdf graph appears
• enter 0 in either min or max date
• error

[ncarazon]

Ready for testing on dev

[SylvainChevalier]

Doesn't crash anymore, but now when I enter an invalid date it doesn't show an error until I try to submit.

Steps:

1. create date question
2. enter invalid min or max date
3. get error message (as expected)
4. change to valid min and max dates
5. error message disappears (as expected)
6. change to invalid min or max date again
7. no error message (there should be one)

[ncarazon]

Ready for testing on dev

[SylvainChevalier]

lgtm.