Add workaround for parameter failure with data being in Rust now

qiskit_algorithms/gradients/reverse/derive_circuit.py

@@ -161,6 +161,9 @@ def derive_circuit(
         c = complex(1)
         for i, term in enumerate(product_rule_term):
             c *= term[0]
+            # Qiskit changed the format of the stored value. The newer Qiskit has this internal
+            # method to go from the older (legacy) format to new. This logic may need updating
+            # at some point if this internal method goes away.
             if hasattr(summand_circuit.data, "_resolve_legacy_value"):
                 value = summand_circuit.data._resolve_legacy_value(term[1], *op_context[i])
                 summand_circuit.data.append(value)

qiskit_algorithms/gradients/utils.py

@@ -1,6 +1,6 @@
 # This code is part of a Qiskit project.
 #
-# (C) Copyright IBM 2022, 2023.
+# (C) Copyright IBM 2022, 2024.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -137,6 +137,13 @@ def _make_lin_comb_gradient_circuit(
                 lin_comb_circuit.h(qr_aux)
                 if add_measurement:
                     lin_comb_circuit.measure(qr_aux, cr_aux)
+                # This next line which assigns data is a workaround otherwise the
+                # circuit parameters may not be properly recognized as data is now
+                # managed in Rust and changing things may break parameters - making a
+                # copy of itself by assignment sorts things out.
+                # See https://github.com/Qiskit/qiskit/blob/main/releasenotes/notes
+                #     /circuit-gates-rust-5c6ab6c58f7fd2c9.yaml#L47-L79
+                lin_comb_circuit.data = lin_comb_circuit.data
                 lin_comb_circuits[p] = lin_comb_circuit
 
     return lin_comb_circuits