similar doesn't preserve the sparsity pattern

Author: avik-pal

Project.toml

@@ -1,7 +1,7 @@
 name = "SparseDiffTools"
 uuid = "47a9eef4-7e08-11e9-0b38-333d64bd3804"
 authors = ["Pankaj Mishra <pankajmishra1511@gmail.com>", "Chris Rackauckas <contact@chrisrackauckas.com>"]
-version = "2.7.0"
+version = "2.8.0"
 
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"

src/highlevel/common.jl

@@ -260,6 +260,7 @@ function init_jacobian(c::AbstractMaybeSparseJacobianCache)
 end
 init_jacobian(::Nothing, ::Type{T}, fx, x) where {T} = similar(fx, T, length(fx), length(x))
 init_jacobian(J, ::Type{T}, _, _) where {T} = similar(J, T, size(J, 1), size(J, 2))
+init_jacobian(J::SparseMatrixCSC, ::Type{T}, _, _) where {T} = T.(J)
 
 __maybe_copy_x(_, x) = x
 __maybe_copy_x(_, ::Nothing) = nothing