don't mutate solution

Author: ChrisRackauckas

src/integrators/integrator_utils.jl

@@ -65,23 +65,23 @@ end
       warn("Max Iters Reached. Aborting")
     end
     postamble!(integrator)
-    integrator.sol.retcode = :MaxIters
+    integrator.sol = solution_new_retcode(integrator.sol,:MaxIters)
     return integrator.sol
   end
   if !integrator.opts.force_dtmin && integrator.opts.adaptive && abs(integrator.dt) <= abs(integrator.opts.dtmin)
     if integrator.opts.verbose
       warn("dt <= dtmin. Aborting. If you would like to force continuation with dt=dtmin, set force_dtmin=true")
     end
     postamble!(integrator)
-    integrator.sol.retcode = :DtLessThanMin
+    integrator.sol = solution_new_retcode(integrator.sol,:DtLessThanMin)
     return integrator.sol
   end
   if integrator.opts.unstable_check(integrator.dt,integrator.t,integrator.u)
     if integrator.opts.verbose
       warn("Instability detected. Aborting")
     end
     postamble!(integrator)
-    integrator.sol.retcode = :Unstable
+    integrator.sol = solution_new_retcode(integrator.sol,:Unstable)
     return integrator.sol
   end
 end

src/solve.jl

@@ -438,6 +438,6 @@ function solve!(integrator::SDEIntegrator)
   if has_analytic(f)
     calculate_solution_errors!(integrator.sol;timeseries_errors=integrator.opts.timeseries_errors,dense_errors=integrator.opts.dense_errors)
   end
-  integrator.sol.retcode = :Success
+  integrator.sol = solution_new_retcode(integrator.sol,:Success)
   nothing
 end