invalid Assertion in BalanceISODate

[FrankYFTang]

https://tc39.es/proposal-temporal/#sec-temporal-balanceisodate has the following code

1. Let epochDays be MakeDay(𝔽(year), 𝔽(month - 1), 𝔽(day)).
2. Assert: epochDays is finite.
   ...

From https://github.com/tc39/test262/blob/main/test/built-ins/Temporal/Calendar/prototype/dateAdd/argument-duration-years-and-months-number-max-value.js
Let's has

var cal = new Temporal.Calendar("iso8601");
var date = new Temporal.PlainDate(1970, 1, 1);
var maxValue = new Temporal.Duration(Number.MAX_VALUE, Number.MAX_VALUE);
cal.dateAdd(date, maxValue)

Now, we will get into
AddISODate ( year, month, day, years, months, weeks, days, overflow )

as
AddISODate ( 1970, 1, 1, Number.MAX_VALUE, Number.MAX_VALUE, 0, 0, overflow )

and get into BalanceISODate() with a not finite years and therefore MakeDay() will return a NaN

But then we will have this assertion violation
2. Assert: epochDays is finite.

Or did I missed something? @ptomato @anba @ljharb @gibson042 @sffc @ryzokuken

[FrankYFTang]

@anba

could you tell me where is the throw of the RangeError in
https://github.com/tc39/test262/blob/main/test/built-ins/Temporal/Calendar/prototype/dateAdd/argument-duration-years-and-months-number-max-value.js

"! BalanceISOYearMonth(....)" won't throw, right?

[anba]

Yes, MakeDay callers currently don't handle too large values → #2315.

could you tell me where is the throw of the RangeError in

It should probably throw in BalanceISOYearMonth or RegulateISODate (*), but it'll definitely throw in CreateTemporalDate.

(*) RegulateISODate can't handle infinities, because it calls ISODaysInMonth, which in turn calls InLeapYear, which in turn calls DaysInYear, and DaysInYear applies ℝ on its input and ℝ(Infinity) isn't defined. Infinity is computed earlier when evaluating TimeFromYear(𝔽(year)) with year = Number.MAX_VALUE.

[FrankYFTang]

ok, I think I misread. your comment earlier on. so you mean that should be throw earlier on in BalanceISOYearMonth but the spec text currently does not throw, right?

[FrankYFTang]

It should probably throw in BalanceISOYearMonth or RegulateISODate

Is that enough? What if in the input weeks is Number.MAX_VALUE or days is Number.MAX_VALUE ? that will make BalanceISOYearMonth or RegulateISODate not throwing (since neither weeks or days are used for that two calls) but will/may reach BalanceISODate with a date = Infinity right?

[anba]

Yes, when either weeks or days is too large, additional error handling is needed, but that can probably be handled through #2315.

[anba]

so you mean that should be throw earlier on in BalanceISOYearMonth but the spec text currently does not throw, right?

Yes, exactly that.

[ptomato]

I think this is covered by #2315. Thanks for the code example, I'll copy it over there.