Fix for Qiskit#2291

InvictusWingsSRL · Jan 25, 2025 · d37ab9b · d37ab9b
1 parent 0bd1716
commit d37ab9b
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diff --git a/releasenotes/notes/aggregate_operations-crash-c262132ba430972d.yaml b/releasenotes/notes/aggregate_operations-crash-c262132ba430972d.yaml
@@ -0,0 +1,9 @@
+---
+prelude: >
+    DiagonalFusion::aggregate_operations could crash in some circumstances
+fixes:
+  - |
+    Sometimes `DiagonalFuson::get_next_deagonal_end` had an invalid `from`
+    parameter. Now it has a check to return -1 in such a case. For more
+    details refer to: `#2291 <https://github.com/Qiskit/qiskit-aer/issues/2291>`
+
diff --git a/src/transpile/fusion.hpp b/src/transpile/fusion.hpp
@@ -579,6 +579,9 @@ int DiagonalFusion::get_next_diagonal_end(
     const oplist_t &ops, const int from, const int end,
     std::set<uint_t> &fusing_qubits) const {
 
+  if (ops.size() <= from)
+    return -1;
+
   if (is_diagonal_op(ops[from])) {
     for (const auto qubit : ops[from].qubits)
       fusing_qubits.insert(qubit);