Add type annotations to part of the public API

qiskit_ionq/__init__.py

@@ -26,8 +26,6 @@
 
 """Provider for IonQ backends"""
 
-import warnings
-
 # warn if qiskit is not installed
 try:
     from qiskit.version import get_version_info  # pylint: disable=unused-import
@@ -41,3 +39,14 @@
 from .ionq_gates import GPIGate, GPI2Gate, MSGate, ZZGate
 from .constants import ErrorMitigation
 from .ionq_equivalence_library import add_equivalences
+
+__all__ = [
+    "__version__",
+    "IonQProvider",
+    "GPIGate",
+    "GPI2Gate",
+    "MSGate",
+    "ZZGate",
+    "ErrorMitigation",
+    "add_equivalences",
+]

qiskit_ionq/exceptions.py

@@ -25,6 +25,10 @@
 # limitations under the License.
 
 """Exceptions for the IonQ Provider."""
+from __future__ import annotations
+
+from typing import Literal
+
 import json.decoder as jd
 
 import requests
@@ -36,10 +40,10 @@
 class IonQError(QiskitError):
     """Base class for errors raised by an IonQProvider."""
 
-    def __str__(self):
+    def __str__(self) -> str:
         return f"{self.__class__.__name__}({self.message!r})"
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return repr(str(self))
 
 
@@ -94,7 +98,7 @@ class IonQAPIError(IonQError):
     """
 
     @classmethod
-    def raise_for_status(cls, response):
+    def raise_for_status(cls, response) -> IonQAPIError:
         """Raise an instance of the exception class from an API response object if needed.
         Args:
             response (:class:`Response <requests.Response>`): An IonQ REST API response.
@@ -111,7 +115,7 @@ def raise_for_status(cls, response):
         raise res
 
     @classmethod
-    def from_response(cls, response):
+    def from_response(cls, response: requests.Response) -> IonQAPIError:
         """Raise an instance of the exception class from an API response object.
 
         Args:
@@ -187,7 +191,7 @@ class IonQGateError(IonQError, JobError):
         gate_name: The name of the gate which caused this error.
     """
 
-    def __init__(self, gate_name, gateset):
+    def __init__(self, gate_name: str, gateset: Literal["qis", "native"]):
         self.gate_name = gate_name
         self.gateset = gateset
         super().__init__(
@@ -210,7 +214,7 @@ class IonQMidCircuitMeasurementError(IonQError, JobError):
         qubit_index: The qubit index to be measured mid-circuit
     """
 
-    def __init__(self, qubit_index, gate_name):
+    def __init__(self, qubit_index: int, gate_name: str):
         self.qubit_index = qubit_index
         self.gate_name = gate_name
         super().__init__(

qiskit_ionq/helpers.py

@@ -29,17 +29,25 @@
 to IonQ REST API compatible values.
 """
 
+from __future__ import annotations
+
 import json
 import gzip
 import base64
 import platform
 import warnings
 import os
+from typing import Literal
 import requests
 from dotenv import dotenv_values
 
 from qiskit import __version__ as qiskit_terra_version
-from qiskit.circuit import controlledgate as q_cgates
+from qiskit.circuit import (
+    controlledgate as q_cgates,
+    QuantumCircuit,
+    QuantumRegister,
+    ClassicalRegister,
+)
 from qiskit.circuit.library import standard_gates as q_gates
 
 # Use this to get version instead of __version__ to avoid circular dependency.
@@ -133,7 +141,9 @@
 }
 
 
-def qiskit_circ_to_ionq_circ(input_circuit, gateset="qis"):
+def qiskit_circ_to_ionq_circ(
+    input_circuit: QuantumCircuit, gateset: Literal["qis", "native"] = "qis"
+):
     """Build a circuit in IonQ's instruction format from qiskit instructions.
 
     .. ATTENTION:: This function ignores the following compiler directives:
@@ -273,7 +283,9 @@ def qiskit_circ_to_ionq_circ(input_circuit, gateset="qis"):
     return output_circuit, num_meas, meas_map
 
 
-def get_register_sizes_and_labels(registers):
+def get_register_sizes_and_labels(
+    registers: list[QuantumRegister | ClassicalRegister],
+) -> tuple[list, list]:
     """Returns a tuple of sizes and labels in for a given register
 
     Args:
@@ -299,7 +311,7 @@ def get_register_sizes_and_labels(registers):
     return sizes, labels
 
 
-def compress_to_metadata_string(metadata):  # pylint: disable=invalid-name
+def compress_to_metadata_string(metadata: dict | list) -> str:  # pylint: disable=invalid-name
     """
     Convert a metadata object to a compact string format (dumped, gzipped, base64 encoded)
     for storing in IonQ API metadata
@@ -318,7 +330,7 @@ def compress_to_metadata_string(metadata):  # pylint: disable=invalid-name
     return encoded.decode()
 
 
-def decompress_metadata_string(input_string):  # pylint: disable=invalid-name
+def decompress_metadata_string(input_string: str) -> dict | list:  # pylint: disable=invalid-name
     """
     Convert compact string format (dumped, gzipped, base64 encoded) from
     IonQ API metadata back into a dict or list of dicts relevant to building
@@ -366,7 +378,7 @@ def qiskit_to_ionq(
     else:
         ionq_circs, _, meas_map = qiskit_circ_to_ionq_circ(circuit, backend.gateset())
         circuit = [circuit]
-
+    circuit: list[QuantumCircuit] | tuple[QuantumCircuit, ...]
     metadata_list = [
         {
             "memory_slots": circ.num_clbits,  # int
@@ -479,7 +491,6 @@ def default(self, o):
         return "unknown"
 
 
-
 def resolve_credentials(token: str = None, url: str = None):
     """Resolve credentials for use in IonQ API calls.
 
@@ -516,7 +527,6 @@ def resolve_credentials(token: str = None, url: str = None):
     }
 
 
-
 def get_n_qubits(backend: str, _fallback=100) -> int:
     """Get the number of qubits for a given backend.