fix: fix MTKBifurcationKitExt (hack)

Author: AayushSabharwal

ext/MTKBifurcationKitExt.jl

@@ -27,7 +27,7 @@ struct ObservableRecordFromSolution{S, T}
             plot_var,
             bif_idx,
             u0_vals,
-            p_vals) where {S, T}
+            p_vals)
         obs_eqs = observed(nsys)
         target_obs_idx = findfirst(isequal(plot_var, eq.lhs) for eq in observed(nsys))
         state_end_idxs = length(unknowns(nsys))
@@ -91,10 +91,18 @@ function BifurcationKit.BifurcationProblem(nsys::NonlinearSystem,
     if !ModelingToolkit.iscomplete(nsys)
         error("A completed `NonlinearSystem` is required. Call `complete` or `structural_simplify` on the system before creating a `BifurcationProblem`")
     end
+    # ModelingToolkit.@set! nsys.index_cache = nothing
     # Creates F and J functions.
     ofun = NonlinearFunction(nsys; jac = jac)
-    F = ofun.f
-    J = jac ? ofun.jac : nothing
+    F(u, p) = ofun.f(u, ModelingToolkit.MTKParameters(nsys, parameters(nsys) .=> p))
+    F(u, p::ModelingToolkit.MTKParameters) = ofun.f(u, p)
+    J = if jac
+        _jac(u, p) = ofun.jac(u, ModelingToolkit.MTKParameters(nsys, parameters(nsys) .=> p))
+        _jac(u, p::ModelingToolkit.MTKParameters) = ofun.jac(u, p)
+        _jac
+    else
+        nothing
+    end
 
     # Converts the input state guess.
     u0_bif_vals = ModelingToolkit.varmap_to_vars(u0_bif,