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Bug #6120

Float and BigDecimal bug in remainder in corner cases

Added by marcandre (Marc-Andre Lafortune) almost 9 years ago. Updated about 3 years ago.

Status:
Assigned
Priority:
Normal
Target version:
-
[ruby-core:43109]
Tags:

Description

Currently:

4.2.remainder(+Float::INFINITY) # => 4.2, ok
4.2.remainder(-Float::INFINITY) # => NaN, should be 4.2
# (same with all signs reversed)

Reasons the remainder should be 4.2 and not NaN:
1) foo.remainder(bar) == foo.remainder(-bar)
2) foo.remainder(bar) == foo when bar.abs > foo.abs

Similarly:
require 'bigdecimal'
bd = BigDecimal.new("4.2")
bd.remainder(BigDecimal.new("+Infinity")) # => NaN, should be bd
bd.remainder(BigDecimal.new("-Infinity")) # => NaN, should be bd
# (same with all signs reverse)

Reasons: same as float.

Finally:
bd = BigDecimal.new("4.2")
bd.modulo(BigDecimal.new("0")) # => ZeroDivisionError, probably ok?
bd.remainder(BigDecimal.new("0")) # => NaN, should be probably raise a ZeroDivisionError?

Like in #6044, this could be decided either way, as long as there is consistency. Anyone prefer NaN to raising a ZeroDivisionError?

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