Add checks for lengths of eqs, dvs, and u0

Fix #936

Author: YingboMa

src/systems/abstractsystem.jl

@@ -547,3 +547,16 @@ Base.showerror(io::IO, e::InvalidSystemException) = print(io, "InvalidSystemExce
 AbstractTrees.children(sys::ModelingToolkit.AbstractSystem) = ModelingToolkit.get_systems(sys)
 AbstractTrees.printnode(io::IO, sys::ModelingToolkit.AbstractSystem) = print(io, nameof(sys))
 AbstractTrees.nodetype(::ModelingToolkit.AbstractSystem) = ModelingToolkit.AbstractSystem
+
+function check_eqs_u0(eqs, dvs, u0)
+    if u0 !== nothing
+        if !(length(eqs) == length(dvs) == length(u0))
+            throw(ArgumentError("Equations ($(length(eqs))), states ($(length(dvs))), and initial conditions ($(length(u0))) are of different lengths."))
+        end
+    else
+        if !(length(eqs) == length(dvs))
+            throw(ArgumentError("Equations ($(length(eqs))), states ($(length(dvs))) are of different lengths."))
+        end
+    end
+    return nothing
+end

src/systems/diffeqs/abstractodesystem.jl

@@ -284,16 +284,15 @@ function process_DEProblem(constructor, sys::AbstractODESystem,u0map,parammap;
                            linenumbers = true, parallel=SerialForm(),
                            eval_expression = true,
                            kwargs...)
+    eqs = equations(sys)
     dvs = states(sys)
     ps = parameters(sys)
     defs = defaults(sys)
 
     u0 = varmap_to_vars(u0map,dvs; defaults=defs)
     p = varmap_to_vars(parammap,ps; defaults=defs)
 
-    if u0 !== nothing
-        length(dvs) == length(u0) || throw(ArgumentError("States ($(length(dvs))) and initial conditions ($(length(u0))) are of different lengths."))
-    end
+    check_eqs_u0(eqs, dvs, u0)
 
     f = constructor(sys,dvs,ps,u0;tgrad=tgrad,jac=jac,checkbounds=checkbounds,
                     linenumbers=linenumbers,parallel=parallel,simplify=simplify,

src/systems/nonlinear/nonlinearsystem.jl

@@ -204,15 +204,14 @@ function process_NonlinearProblem(constructor, sys::NonlinearSystem,u0map,paramm
                            linenumbers = true, parallel=SerialForm(),
                            eval_expression = true,
                            kwargs...)
+    eqs = equations(sys)
     dvs = states(sys)
     ps = parameters(sys)
     defs = defaults(sys)
     u0 = varmap_to_vars(u0map,dvs; defaults=defs)
     p = varmap_to_vars(parammap,ps; defaults=defs)
 
-    if u0 !== nothing
-        length(dvs) == length(u0) || throw(ArgumentError("States ($(length(dvs))) and initial conditions ($(length(u0))) are of different lengths."))
-    end
+    check_eqs_u0(eqs, dvs, u0)
 
     f = constructor(sys,dvs,ps,u0;jac=jac,checkbounds=checkbounds,
                     linenumbers=linenumbers,parallel=parallel,simplify=simplify,

test/nonlinearsystem.jl

@@ -87,6 +87,7 @@ eqs1 = [
 
 lorenz = name -> NonlinearSystem(eqs1, [x,y,z,u,F], [σ,ρ,β], name=name)
 lorenz1 = lorenz(:lorenz1)
+@test_throws ArgumentError NonlinearProblem(lorenz1, zeros(5))
 lorenz2 = lorenz(:lorenz2)
 connected = NonlinearSystem([s ~ a + lorenz1.x
                              lorenz2.y ~ s