fix: complete with split = false removes the index cache

Author: AayushSabharwal

src/systems/abstractsystem.jl

@@ -985,6 +985,8 @@ function complete(sys::AbstractSystem; split = true, flatten = true)
             end
             @set! sys.ps = ordered_ps
         end
+    elseif has_index_cache(sys)
+        @set! sys.index_cache = nothing
     end
     if isdefined(sys, :initializesystem) && get_initializesystem(sys) !== nothing
         @set! sys.initializesystem = complete(get_initializesystem(sys); split)

test/odesystem.jl

@@ -1495,3 +1495,12 @@ end
     sys2 = complete(sys)
     @test length(equations(sys2)) == total_eqs
 end
+
+@testset "`complete` with `split = false` removes the index cache" begin
+    @variables x(t)
+    @parameters p
+    @mtkbuild sys = ODESystem(D(x) ~ p * t, t)
+    @test ModelingToolkit.get_index_cache(sys) !== nothing
+    sys2 = complete(sys; split = false)
+    @test ModelingToolkit.get_index_cache(sys2) === nothing
+end