[8570]fix: raise exception for years less than 1600

[StrawHatDrag0n]

fix pydantic/pydantic#8570

[codecov]

Codecov Report

Merging #55 (025d840) into main (ef53708) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #55   +/-   ##
=======================================
  Coverage   99.12%   99.13%           
=======================================
  Files           6        6           
  Lines         918      922    +4     
=======================================
+ Hits          910      914    +4     
  Misses          8        8           

Files	Coverage Δ
src/date.rs	100.00% <100.00%> (ø)
src/lib.rs	91.66% <ø> (ø)

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[davidhewitt]

I'm afraid I don't agree with this change, nor the suggestion that raising a more informative error is the correct fix.

I think most likely the source of the panic is on the following line, where year is a u16 so subtracting 1600 from it is incorrect for years under 1600

speedate/src/date.rs

Line 231 in ef53708

let days = (self.year - 1600) as i64 * 365

Probably it would be more correct as (self.year as i64 - 1600) * 365, as i64 can go below 0.

There's a slight follow up question of what the limits of that timestamp() function would be, probably operations in that function which we think can overflow should use .checked_mul() / .checked_sub()

[davidhewitt]

Adding this here will break pydantic's ability to parse all dates before 1600, whereas currently the issue only exists for FutureDatetime (and I guess PastDatetime).