From 55d81af15d274d094a4c50f3e6ae82e6321d5d13 Mon Sep 17 00:00:00 2001
From: Aayush Sabharwal <aayush.sabharwal@juliahub.com>
Date: Mon, 3 Jun 2024 17:00:33 +0530
Subject: [PATCH] fix: fix incorrect dimensionality of `ODESolution` in
 `build_function` and `@set`

---
 ext/SciMLBaseZygoteExt.jl      | 10 +---------
 src/solutions/ode_solutions.jl | 12 +++++++++++-
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/ext/SciMLBaseZygoteExt.jl b/ext/SciMLBaseZygoteExt.jl
index 2f7399f11..58e7bb309 100644
--- a/ext/SciMLBaseZygoteExt.jl
+++ b/ext/SciMLBaseZygoteExt.jl
@@ -58,15 +58,7 @@ end
             du, dprob
         end
         T = eltype(eltype(VA.u))
-        if dprob.u0 === nothing
-            N = 2
-        elseif dprob isa SciMLBase.BVProblem && !hasmethod(size, Tuple{typeof(dprob.u0)})
-            __u0 = hasmethod(dprob.u0, Tuple{typeof(dprob.p), typeof(first(dprob.tspan))}) ?
-                   dprob.u0(dprob.p, first(dprob.tspan)) : dprob.u0(first(dprob.tspan))
-            N = length((size(__u0)..., length(du)))
-        else
-            N = length((size(dprob.u0)..., length(du)))
-        end
+        N = ndims(VA)
         Δ′ = ODESolution{T, N}(du, nothing, nothing,
             VA.t, VA.k, dprob, VA.alg, VA.interp, VA.dense, 0, VA.stats,
             VA.alg_choice, VA.retcode)
diff --git a/src/solutions/ode_solutions.jl b/src/solutions/ode_solutions.jl
index 7c22f9b4a..5636c4993 100644
--- a/src/solutions/ode_solutions.jl
+++ b/src/solutions/ode_solutions.jl
@@ -129,6 +129,16 @@ function ConstructionBase.constructorof(::Type{O}) where {T, N, O <: ODESolution
     ODESolution{T, N}
 end
 
+function ConstructionBase.setproperties(sol::ODESolution, patch::NamedTuple)
+    u = get(patch, :u, sol.u)
+    N = u === nothing ? 2 : ndims(eltype(u)) + 1
+    T = eltype(eltype(u))
+    patch = merge(getproperties(sol), patch)
+    return ODESolution{T, N}(patch.u, patch.u_analytic, patch.errors, patch.t, patch.k,
+        patch.prob, patch.alg, patch.interp, patch.dense, patch.tslocation, patch.stats,
+        patch.alg_choice, patch.retcode, patch.resid, patch.original)
+end
+
 Base.@propagate_inbounds function Base.getproperty(x::AbstractODESolution, s::Symbol)
     if s === :destats
         Base.depwarn("`sol.destats` is deprecated. Use `sol.stats` instead.", "sol.destats")
@@ -276,7 +286,7 @@ function build_solution(prob::Union{AbstractODEProblem, AbstractDDEProblem},
                prob.u0(prob.p, first(prob.tspan)) : prob.u0(first(prob.tspan))
         N = length((size(__u0)..., length(u)))
     else
-        N = length((size(prob.u0)..., length(u)))
+        N = ndims(eltype(u)) + 1
     end
 
     if prob.f isa Tuple