Error in iszero in Julia v1.10

[andreasvarga]

The following works well in Julia 1.9 but fails in Julia 1.10

In Julia 1.9:

julia> Af = Fun(t -> [0  1; -10*cos(t)-1 -24-19*sin(t)],Fourier(0..2pi));
julia> iszero(Af)
false

The old definition ofiszero is

iszero(f::Fun) = all(iszero,f.coefficients)

In Julia 1.10:

julia> Af = Fun(t -> [0  1; -10*cos(t)-1 -24-19*sin(t)],Fourier(0..2pi));
julia> iszero(Af)
ERROR: Override for ApproxFunBase.ArraySpace(ApproxFunBase.SumSpace{Tuple{CosSpace{PeriodicSegment{Float64}, Float64}, SinSpace{PeriodicSegment{Float64}, Float64}}, PeriodicSegment{Float64}, Float64}[Fourier(【0.0,6.283185307179586❫) Fourier(【0.0,6.283185307179586❫); Fourier(【0.0,6.283185307179586❫) Fourier(【0.0,6.283185307179586❫)])
Stacktrace:
 [1] error(s::String)
   @ Base .\error.jl:35
 [2] checkcanonicalspace(sp::ApproxFunBase.ArraySpace{ApproxFunBase.SumSpace{…}, 2, PeriodicSegment{…}, Float64, Matrix{…}})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:478
 [3] ApproxFunBase.ICanonicalTransformPlan(space::ApproxFunBase.ArraySpace{…}, v::Vector{…}, ip::Val{…})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:493
 [4] plan_itransform(sp::ApproxFunBase.ArraySpace{…}, v::Vector{…})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:497
 [5] itransform(S::ApproxFunBase.ArraySpace{…}, cfs::Vector{…})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:564
 [6] _values
   @ C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Fun.jl:428 [inlined]
 [7] values
   @ C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Fun.jl:426 [inlined]
 [8] iszero(f::Fun{ApproxFunBase.ArraySpace{…}, Float64, Vector{…}})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Fun.jl:776
 [9] top-level scope
   @ REPL[90]:1
Some type information was truncated. Use `show(err)` to see complete types.

The new definition ofiszero is

iszero(f::Fun) = all(iszero, coefficients(f)) || all(iszero, values(f))

so, the failure is caused by

julia> values(Af)
ERROR: Override for ApproxFunBase.ArraySpace(ApproxFunBase.SumSpace{Tuple{CosSpace{PeriodicSegment{Float64}, Float64}, SinSpace{PeriodicSegment{Float64}, Float64}}, PeriodicSegment{Float64}, Float64}[Fourier(【0.0,6.283185307179586❫) Fourier(【0.0,6.283185307179586❫); Fourier(【0.0,6.283185307179586❫) Fourier(【0.0,6.283185307179586❫)])
Stacktrace:
 [1] error(s::String)
   @ Base .\error.jl:35
 [2] checkcanonicalspace(sp::ApproxFunBase.ArraySpace{ApproxFunBase.SumSpace{…}, 2, PeriodicSegment{…}, Float64, Matrix{…}})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:478
 [3] ApproxFunBase.ICanonicalTransformPlan(space::ApproxFunBase.ArraySpace{…}, v::Vector{…}, ip::Val{…})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:493
 [4] plan_itransform(sp::ApproxFunBase.ArraySpace{…}, v::Vector{…})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:497
 [5] itransform(S::ApproxFunBase.ArraySpace{…}, cfs::Vector{…})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Space.jl:564
 [6] _values
   @ C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Fun.jl:428 [inlined]
 [7] values(::Fun{ApproxFunBase.ArraySpace{…}, Float64, Vector{…}})
   @ ApproxFunBase C:\Users\Andreas\.julia\packages\ApproxFunBase\sJBXX\src\Fun.jl:426
 [8] top-level scope
   @ REPL[91]:1
Some type information was truncated. Use `show(err)` to see complete types.

I wonder why the second test involving all(iszero, values(f)) is necessary!

I would appreciate very much if the fix for this very basic function can be done in a short time. Thanks in advance.

[jishnub]

IIRC the values was used for piecewise or sum spaces, where the coefficients may not be zero, but the function may still be zero. However, looks like values isn't defined for an ArraySpace.