Compiled `autodiff` returns more stuff?

[gdalle]

I just discovered that autodiff inside and outside of Reactant compilation produce different results:

julia> using Reactant, Enzyme

julia> x = ones(2);

julia> xr = Reactant.to_rarray(x);

julia> autodiff(Reverse, sum, Duplicated(x, zero(x)))
((nothing,),)

julia> @jit autodiff(Reverse, sum, Duplicated(xr, zero(xr)))  # why does this return something different?
((nothing,), nothing)

Found it while working on DI integration in JuliaDiff/DifferentiationInterface.jl#918, it errored because I was using only(autodiff(...))

[wsmoses]

probably a bug in parsing the mode in here

Reactant.jl/src/Enzyme.jl

Line 499 in 5ef447d

resv = if EnzymeCore.needs_primal(CMode)

if you want to give it a look

[wsmoses]

specifically it should likely just return without the extra element of the tuple rather than adding the extra nothing if not needs_primal