From 94edf0bf3e2096dc65d0265767b87d7b052e5324 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lars=20G=C3=B6ttgens?= <lars.goettgens@rwth-aachen.de>
Date: Mon, 9 Mar 2026 12:20:44 +0100
Subject: [PATCH] Fix deserilization of `SMat` with trailing zero cols

---
 src/Serialization/Rings.jl     | 2 ++
 test/Serialization/Matrices.jl | 1 +
 2 files changed, 3 insertions(+)

diff --git a/src/Serialization/Rings.jl b/src/Serialization/Rings.jl
index 698c687d6a70..49259d7d71c8 100644
--- a/src/Serialization/Rings.jl
+++ b/src/Serialization/Rings.jl
@@ -380,6 +380,8 @@ function load_object(s::DeserializerState, ::Type{<:SMat}, parent::SMatSpace{T})
     end
     push!(M, sparse_row(base, row_entries))
   end
+  M.c = parent.cols
+  @assert nrows(M) == parent.rows
   return M
 end
 
diff --git a/test/Serialization/Matrices.jl b/test/Serialization/Matrices.jl
index 1e98a3468088..77a437c104a2 100644
--- a/test/Serialization/Matrices.jl
+++ b/test/Serialization/Matrices.jl
@@ -14,6 +14,7 @@ cases = [
   (Fin, [d d^3; d^2 0]),
   (Frac, [1 // x x^2; 3 0]),
   (A, [(f^3 + g^2) f^2; g (a*f + 1)]),
+  (ZZ, [0 0 0; 0 0 0]), # issue #5849
 ]
 
 @testset "Matrices" begin