StackOverflow in forward mode

[gdalle]

julia> using Enzyme

julia> g(x::Number) = [sin(x) cos(x); sin(2x) cos(2x)]
g (generic function with 1 method)

julia> autodiff(Forward, g, Duplicated, Duplicated(1.0, 1.0))
ERROR: StackOverflowError:
Stacktrace:
     [1] hvcat
       @ ~/.julia/juliaup/julia-1.10.2+0.x64.linux.gnu/share/julia/stdlib/v1.10/SparseArrays/src/sparsevector.jl:1269 [inlined]
     [2] hvcat
       @ ~/.julia/juliaup/julia-1.10.2+0.x64.linux.gnu/share/julia/stdlib/v1.10/SparseArrays/src/sparsevector.jl:0 [inlined]
     [3] fwddiffejulia_hvcat_6909_inner_1wrap
       @ ~/.julia/juliaup/julia-1.10.2+0.x64.linux.gnu/share/julia/stdlib/v1.10/SparseArrays/src/sparsevector.jl:0
     [4] macro expansion
       @ ~/.julia/packages/Enzyme/wR2t7/src/compiler.jl:5378 [inlined]
     [5] enzyme_call
       @ ~/.julia/packages/Enzyme/wR2t7/src/compiler.jl:5056 [inlined]
     [6] ForwardModeThunk
       @ ~/.julia/packages/Enzyme/wR2t7/src/compiler.jl:5001 [inlined]
     [7] runtime_generic_fwd(activity::Type{…}, width::Val{…}, RT::Val{…}, f::typeof(hvcat), df::Nothing, primal_1::Tuple{…}, shadow_1_1::Nothing, primal_2::Float64, shadow_2_1::Float64, primal_3::Float64, shadow_3_1::Float64, primal_4::Float64, shadow_4_1::Float64, primal_5::Float64, shadow_5_1::Float64)
       @ Enzyme.Compiler ~/.julia/packages/Enzyme/wR2t7/src/rules/jitrules.jl:116
--- the last 7 lines are repeated 5630 more times ---
 [39418] hvcat
       @ ~/.julia/juliaup/julia-1.10.2+0.x64.linux.gnu/share/julia/stdlib/v1.10/SparseArrays/src/sparsevector.jl:1269 [inlined]
 [39419] g
       @ ~/Work/GitHub/Julia/DifferentiationInterface.jl/test/enzyme.jl:18 [inlined]
 [39420] fwddiffejulia_g_9702wrap
       @ ~/Work/GitHub/Julia/DifferentiationInterface.jl/test/enzyme.jl:0
 [39421] macro expansion
       @ ~/.julia/packages/Enzyme/wR2t7/src/compiler.jl:5378 [inlined]
 [39422] enzyme_call
       @ ~/.julia/packages/Enzyme/wR2t7/src/compiler.jl:5056 [inlined]
 [39423] ForwardModeThunk
       @ ~/.julia/packages/Enzyme/wR2t7/src/compiler.jl:5001 [inlined]
 [39424] autodiff(::ForwardMode{FFIABI}, f::Const{typeof(g)}, ::Type{Duplicated}, args::Duplicated{Float64})
       @ Enzyme ~/.julia/packages/Enzyme/wR2t7/src/Enzyme.jl:324
 [39425] autodiff(::ForwardMode{FFIABI}, ::typeof(g), ::Type, ::Duplicated{Float64})
       @ Enzyme ~/.julia/packages/Enzyme/wR2t7/src/Enzyme.jl:224
Some type information was truncated. Use `show(err)` to see complete types.

[gdalle]

@adrhill this makes our tests fail

[wsmoses]

Duplicate of #1134

Unfortunately this is introduced in Julia 1.10 by JuliaSparse/SparseArrays.jl@c402d09. In interim the recommendation is to not use hvcat (which unfortunately can be generated by type unstable matrix syntax). If you have time a custom rule for hvcat to work around this in the interim would be appreciated (or poking SparseArrays to revert/fix)

[wsmoses]

Closing as duplicate

[gdalle]

Sorry what is this a duplicate of? You linked to the present issue

[wsmoses]

Oh whoops, edited comment above.