Bug for ifft! with empty dimensions

[RainerHeintzmann]

By chance we found a change in behaviour. Probably caused by Julia 1.7.1:
ifft!(rand(ComplexF64,3,4),[])
yields an error:

julia> ifft!(rand(ComplexF64,3,4),[])
ERROR: ArgumentError: reducing over an empty collection is not allowed
Stacktrace:
  [1] _empty_reduce_error()
    @ Base .\reduce.jl:301
  [2] mapreduce_empty(f::Function, op::Base.BottomRF{typeof(Base.mul_prod)}, T::Type)
    @ Base .\reduce.jl:344
  [3] reduce_empty(op::Base.MappingRF{AbstractFFTs.var"#17#18"{Tuple{Int64, Int64}}, Base.BottomRF{typeof(Base.mul_prod)}}, #unused#::Type{Any})
    @ Base .\reduce.jl:331
  [4] reduce_empty_iter
    @ .\reduce.jl:357 [inlined]
  [5] reduce_empty_iter
    @ .\reduce.jl:356 [inlined]
  [6] foldl_impl
    @ .\reduce.jl:49 [inlined]
  [7] mapfoldl_impl
    @ .\reduce.jl:44 [inlined]
  [8] #mapfoldl#244
    @ .\reduce.jl:162 [inlined]
  [9] mapfoldl
    @ .\reduce.jl:162 [inlined]
 [10] #mapreduce#248
    @ .\reduce.jl:289 [inlined]
 [11] mapreduce
    @ .\reduce.jl:289 [inlined]
 [12] #prod#255
    @ .\reduce.jl:588 [inlined]
 [13] prod
    @ .\reduce.jl:588 [inlined]
 [14] normalization(#unused#::Type{Float64}, sz::Tuple{Int64, Int64}, region::Vector{Any})
    @ AbstractFFTs C:\Users\pi96doc\.julia\packages\AbstractFFTs\Ih3rT\src\definitions.jl:259
 [15] normalization
    @ C:\Users\pi96doc\.julia\packages\AbstractFFTs\Ih3rT\src\definitions.jl:260 [inlined]
 [16] #plan_ifft!#20
    @ C:\Users\pi96doc\.julia\packages\AbstractFFTs\Ih3rT\src\definitions.jl:264 [inlined]
 [17] plan_ifft!
    @ C:\Users\pi96doc\.julia\packages\AbstractFFTs\Ih3rT\src\definitions.jl:264 [inlined]
 [18] ifft!(x::Matrix{ComplexF64}, region::Vector{Any})
    @ AbstractFFTs C:\Users\pi96doc\.julia\packages\AbstractFFTs\Ih3rT\src\definitions.jl:51
 [19] top-level scope
    @ REPL[43]:1

[martinholters]

Issue originates in AbstractFFTs.jl, possible fix:

diff --git a/src/definitions.jl b/src/definitions.jl
index 80a6656..bac7127 100644
--- a/src/definitions.jl
+++ b/src/definitions.jl
@@ -256,7 +256,7 @@ summary(p::ScaledPlan) = string(p.scale, " * ", summary(p.p))
 *(p::Plan, I::UniformScaling) = ScaledPlan(p, I.λ)
 
 # Normalization for ifft, given unscaled bfft, is 1/prod(dimensions)
-normalization(::Type{T}, sz, region) where T = one(T) / Int(prod(sz[r] for r in region))::Int
+normalization(::Type{T}, sz, region) where T = one(T) / Int(prod(sz[r] for r in region; init=1))::Int
 normalization(X, region) = normalization(real(eltype(X)), size(X), region)
 
 plan_ifft(x::AbstractArray, region; kws...) =