handle nothing first fsal case

Author: ChrisRackauckas

lib/OrdinaryDiffEqCore/src/caches/basic_caches.jl

@@ -13,7 +13,14 @@ mutable struct CompositeCache{T, F} <: OrdinaryDiffEqCache
     current::Int
 end
 
-get_fsalfirstlast(cache::CompositeCache, u) = get_fsalfirstlast(cache.caches[1], u)
+function get_fsalfirstlast(cache::CompositeCache, u) 
+    _x = get_fsalfirstlast(cache.caches[1], u)
+    if first(_x) !== nothing
+        return _x
+    else
+        return get_fsalfirstlast(cache.caches[2], u)
+    end
+end
 
 mutable struct DefaultCache{T1, T2, T3, T4, T5, T6, A, F, uType} <: OrdinaryDiffEqCache
     args::A

lib/OrdinaryDiffEqCore/src/solve.jl

@@ -471,8 +471,6 @@ function DiffEqBase.__init(
     saveiter_dense = 0
     fsalfirst, fsallast = get_fsalfirstlast(cache, rate_prototype)
 
-    @show typeof(fsalfirst)
-
     integrator = ODEIntegrator{typeof(_alg), isinplace(prob), uType, typeof(du),
         tType, typeof(p),
         typeof(eigen_est), typeof(EEst),