add overflow checking for abs(::Rational) (#48912)

base/rational.jl

@@ -277,7 +277,7 @@ signbit(x::Rational) = signbit(x.num)
 copysign(x::Rational, y::Real) = unsafe_rational(copysign(x.num, y), x.den)
 copysign(x::Rational, y::Rational) = unsafe_rational(copysign(x.num, y.num), x.den)
 
-abs(x::Rational) = Rational(abs(x.num), x.den)
+abs(x::Rational) = unsafe_rational(checked_abs(x.num), x.den)
 
 typemin(::Type{Rational{T}}) where {T<:Signed} = unsafe_rational(T, -one(T), zero(T))
 typemin(::Type{Rational{T}}) where {T<:Integer} = unsafe_rational(T, zero(T), one(T))
@@ -545,7 +545,7 @@ function hash(x::Rational{<:BitInteger64}, h::UInt)
  pow = trailing_zeros(den)
  den >>= pow
  pow = -pow
- if den == 1 && abs(num) < 9007199254740992
+ if den == 1 && uabs(num) < UInt64(maxintfloat(Float64))
  return hash(ldexp(Float64(num),pow),h)
  end
  end

test/hashing.jl

@@ -60,6 +60,9 @@ end
 @test hash(nextfloat(2.0^63)) == hash(UInt64(nextfloat(2.0^63)))
 @test hash(prevfloat(2.0^64)) == hash(UInt64(prevfloat(2.0^64)))
 
+# issue #48744
+@test hash(typemin(Int)//1) === hash(big(typemin(Int)//1))
+
 # issue #9264
 @test hash(1//6,zero(UInt)) == invoke(hash, Tuple{Real, UInt}, 1//6, zero(UInt))
 @test hash(1//6) == hash(big(1)//big(6))

test/rational.jl

@@ -269,6 +269,9 @@ end
  @test read(io2, typeof(rational2)) == rational2
  end
 end
+@testset "abs overflow for Rational" begin
+ @test_throws OverflowError abs(typemin(Int) // 1)
+end
 @testset "parse" begin
  # Non-negative Int in which parsing is expected to work
  @test parse(Rational{Int}, string(10)) == 10 // 1