[C++] Fix Segfault in SparseCSFIndex::Equals with mismatched dimensions

Author: Alirana2829

cpp/src/arrow/sparse_tensor.cc

@@ -405,6 +405,9 @@ SparseCSFIndex::SparseCSFIndex(const std::vector<std::shared_ptr<Tensor>>& indpt
 std::string SparseCSFIndex::ToString() const { return std::string("SparseCSFIndex"); }
 
 bool SparseCSFIndex::Equals(const SparseCSFIndex& other) const {
+  if (indices().size() != other.indices().size() || indptr().size() != other.indptr().size()) {
+    return false;
+  }
   for (int64_t i = 0; i < static_cast<int64_t>(indices().size()); ++i) {
     if (!indices()[i]->Equals(*other.indices()[i])) return false;
   }