🐛 Initialize the Qiskit C API once

bindings/mlir/qiskit/Qiskit2_5.cpp

@@ -1903,16 +1903,18 @@ class NativeTranslation final : public VersionedTranslation {
 std::unique_ptr<VersionedTranslation>
 MQT_QISKIT_VERSION_FACTORY() { // NOLINT(misc-use-internal-linkage): declared in
                                // the version registry.
-  if (qk_import() < 0) {
-    throwPythonError("failed to initialize the Qiskit " MQT_QISKIT_VERSION_LABEL
-                     " C API");
-  }
-  const auto version = qk_api_version();
-  const auto major = (version >> 24U) & 0xffU;
-  const auto minor = (version >> 16U) & 0xffU;
+  static const auto VERSION = []() {
+    if (qk_import() < 0) {
+      throwPythonError(
+          "failed to initialize the Qiskit " MQT_QISKIT_VERSION_LABEL " C API");
+    }
+    return qk_api_version();
+  }();
+  const auto major = (VERSION >> 24U) & 0xffU;
+  const auto minor = (VERSION >> 16U) & 0xffU;
   if (major != MQT_QISKIT_VERSION_EXPECTED_MAJOR ||
       minor != MQT_QISKIT_VERSION_EXPECTED_MINOR ||
-      (MQT_QISKIT_VERSION_EXACT_API != 0 && version != QISKIT_VERSION_HEX)) {
+      (MQT_QISKIT_VERSION_EXACT_API != 0 && VERSION != QISKIT_VERSION_HEX)) {
     throw std::runtime_error("Qiskit C API capsule version does not match the "
                              "selected " MQT_QISKIT_VERSION_LABEL
                              " translation");

test/python/test_mlir_qiskit_translation.py

@@ -14,6 +14,7 @@
 import re
 import subprocess
 import sys
+from concurrent.futures import ThreadPoolExecutor
 from typing import TYPE_CHECKING
 
 import numpy as np
@@ -105,6 +106,18 @@
 )
 
 
+def test_native_api_initialization_supports_concurrent_translation() -> None:
+    """Initialize and reuse the native Qiskit API from concurrent translations."""
+
+    def _round_trip(_: int) -> str:
+        circuit = QuantumCircuit(1)
+        circuit.x(0)
+        return QCProgram.from_qiskit(circuit).to_qiskit().data[0].operation.name
+
+    with ThreadPoolExecutor(max_workers=8) as executor:
+        assert list(executor.map(_round_trip, range(32))) == ["x"] * 32
+
+
 @pytest.mark.parametrize("gate", STANDARD_GATES, ids=lambda gate: gate.name)
 def test_standard_gates_round_trip(gate: Gate) -> None:
     """Translate each supported gate family in both directions."""