Date and DateTime should reject year inputs that they can't store #50981
Description
This MWE was found via fuzzing through PropCheck.jl:
julia> using PropCheck, Dates
julia> year_invariant_dt(y) = try
return Year(DateTime(y)) === Year(y)
catch
return true # caught bad input
end
year_invariant_dt (generic function with 1 method)
julia> year_invariant_d(y) = try
return Year(Date(y)) === Year(y)
catch
return true # caught bad input
end
year_invariant_d (generic function with 1 method)
julia> check(year_invariant_d, PropCheck.iposint(Int, PropCheck.shrinkTowards(typemin(Int))); transform = y -> (Date(y), Year(Date(y)), y))
┌ Info: Found counterexample for 'year_invariant_d', beginning shrinking...
└ Counterexample = 7514048394603581534
[ Info: 842 counterexamples found for year_invariant_d
(Date("-252522163911150-6028347736506387-29"), Year(-252522163911150), 252522163911151)
julia> check(year_invariant_d, PropCheck.inegint(Int, PropCheck.shrinkTowards(typemax(Int))); transform = y -> (Date(y), Year(Date(y)), y))
┌ Info: Found counterexample for 'year_invariant_d', beginning shrinking...
└ Counterexample = -8422004767203074864
[ Info: 784 counterexamples found for year_invariant_d
(Date("252522163911150--6028347736506385--26"), Year(252522163911150), -252522163911151)
julia> check(year_invariant_dt, PropCheck.iposint(Int, PropCheck.shrinkTowards(typemin(Int))); transform = y -> (DateTime(y), Year(DateTime(y)), y))
┌ Info: Found counterexample for 'year_invariant_dt', beginning shrinking...
└ Counterexample = 8427913184424949470
[ Info: 1317 counterexamples found for year_invariant_dt
(DateTime("-292277024-09-29T09:34:08.384"), Year(-292277024), 292277026)
julia> check(year_invariant_dt, PropCheck.inegint(Int, PropCheck.shrinkTowards(typemax(Int))); transform = y -> (DateTime(y), Year(DateTime(y)), y))
┌ Info: Found counterexample for 'year_invariant_dt', beginning shrinking...
└ Counterexample = -7698482265388645055
[ Info: 1060 counterexamples found for year_invariant_dt
(DateTime("292277025-04-03T14:25:51.616"), Year(292277025), -292277024)The DateTime and Date constructors check all their other arguments, so I'd expect the year to be checked as well. For display purposes only, the found values are transformed into a 3-tuple with the contents:
- Date/DateTime
dtthat was constructed (you can see the bad results in here) Year(dt)that was received from the bad Date/DateTime- the year that was given to the constructor
which you can see below the last [ Info: per invocation of check above.
The property that was expected to hold is "The year given to the constructor is the same I get back out, or the constructor rejected the input."
I'm not 100% sure the values found are actually minimally maximal/maximally minimal, as the property only checks the year. It may very well be that there are representable dates larger/smaller than these, where not the whole year can be created without overflowing.