PyO3 panic during SabreLayout

[jakelishman]

Environment

• Qiskit Terra version: main @ bab9d45
• Python version: 3.10/macOS (me) or 3.8/Linux (CI)
• Operating system:

What is happening?

Randomised testing found a case where PyO3 is panicking and reporting "Graph::add_edge: node indices out of bounds" during SabreSwap (triggered by SabreLayout).

How can we reproduce the issue?

from qiskit import QuantumCircuit, transpile
from qiskit.providers.fake_provider import FakeKolkata
qc = QuantumCircuit.from_qasm_str("""
 OPENQASM 2.0;
include "qelib1.inc";
qreg q4833[1];
qreg q4834[6];
qreg q4835[7];
creg c982[2];
creg c983[2];
creg c984[2];
rzz(0) q4833[0],q4834[4];
cu(0,-6.1035156e-05,0,1e-05) q4834[1],q4835[2];
swap q4834[0],q4834[2];
cu(-1.1920929e-07,0,-0.33333333,0) q4833[0],q4834[2];
ccx q4835[2],q4834[5],q4835[4];
measure q4835[4] -> c984[0];
ccx q4835[2],q4835[5],q4833[0];
measure q4835[5] -> c984[1];
measure q4834[0] -> c982[1];
u(10*pi,0,1.9) q4834[5];
measure q4834[3] -> c984[1];
measure q4835[0] -> c982[0];
rz(0) q4835[1];
""")
transpile(qc, FakeKolkata(), layout_method="sabre")

this produces (exception shortened):

thread '<unnamed>' panicked at 'Graph::add_edge: node indices out of bounds', /Users/jake/.cargo/registry/src/github.com-1ecc6299db9ec823/petgraph-0.6.2/src/graph_impl/mod.rs:573:27
---------------------------------------------------------------------------
PanicException                            Traceback (most recent call last)
<ipython-input-5-55111b87744c> in <module>
     24 rz(0) q4835[1];
     25 """)
---> 26 transpile(qc, FakeKolkata(), layout_method="sabre")

< ... transpile pass-manager setup ... >

~/code/qiskit/terra/qiskit/transpiler/passes/layout/sabre_layout.py in run(self, dag)
     97             for _ in ("forward", "backward"):
     98                 pm = self._layout_and_route_passmanager(initial_layout)
---> 99                 new_circ = pm.run(circ)
    100
    101                 # Update initial layout and reverse the unmapped circuit.

< ... SabreLayout's delegated PM setup ... >

~/code/qiskit/terra/qiskit/transpiler/passes/routing/sabre_swap.py in run(self, dag)
    208             )
    209         front_layer = np.asarray([x._node_id for x in dag.front_layer()], dtype=np.uintp)
--> 210         sabre_dag = SabreDAG(len(dag.qubits), len(dag.clbits), dag_list, front_layer)
    211         swap_map, gate_order = build_swap_map(
    212             len(dag.qubits),

PanicException: Graph::add_edge: node indices out of bounds

What should happen?

Successful transpilation - this looks like a potential bug in the new Rusty Sabre handover (#8388).

Any suggestions?

No response