Merge pull request #2869 from SebastianM-C/smc/subs

refactor: avoid substitute warning when not needed

Author: ChrisRackauckas

src/systems/abstractsystem.jl

@@ -2600,8 +2600,10 @@ end
 
 keytype(::Type{<:Pair{T, V}}) where {T, V} = T
 function Symbolics.substitute(sys::AbstractSystem, rules::Union{Vector{<:Pair}, Dict})
-    if has_continuous_domain(sys) && get_continuous_events(sys) !== nothing ||
-       has_discrete_events(sys) && get_discrete_events(sys) !== nothing
+    if has_continuous_domain(sys) && get_continuous_events(sys) !== nothing &&
+       !isempty(get_continuous_events(sys)) ||
+       has_discrete_events(sys) && get_discrete_events(sys) !== nothing &&
+       !isempty(get_discrete_events(sys))
         @warn "`substitute` only supports performing substitutions in equations. This system has events, which will not be updated."
     end
     if keytype(eltype(rules)) <: Symbol

test/odesystem.jl

@@ -972,7 +972,8 @@ vars_sub2 = @variables s2(t)
 @named partial_sub = ODESystem(Equation[], t, vars_sub2, [])
 @named sub = extend(partial_sub, sub)
 
-new_sys2 = complete(substitute(sys2, Dict(:sub => sub)))
+# no warnings for systems without events
+new_sys2 = @test_nowarn complete(substitute(sys2, Dict(:sub => sub)))
 Set(unknowns(new_sys2)) == Set([new_sys2.x1, new_sys2.sys1.x1,
     new_sys2.sys1.sub.s1, new_sys2.sys1.sub.s2,
     new_sys2.sub.s1, new_sys2.sub.s2])