Implement and enforce explicit re-export for cirq modules (quantumlib…

…#6722)

* Enable and enforce the `no_implicit_reexport` mypy rule for cirq modules
* Update `__init__.py` files so they explicitly re-export public symbols, but
  do not re-export local symbols or submodules already in parent namespace
* Fix few instances of imports from incorrect modules

Fixes quantumlib#6717
---------

Co-authored-by: Pavol Juhas <juhas@google.com>

cirq/circuits/__init__.py

@@ -14,15 +14,21 @@
 
 """Circuit classes, mutators, and outputs."""
 
-from cirq.circuits.text_diagram_drawer import TextDiagramDrawer
+from cirq.circuits.text_diagram_drawer import TextDiagramDrawer as TextDiagramDrawer
+from cirq.circuits.qasm_output import QasmOutput as QasmOutput
 
-from cirq.circuits.qasm_output import QasmOutput
+from cirq.circuits.circuit import (
+    AbstractCircuit as AbstractCircuit,
+    Alignment as Alignment,
+    Circuit as Circuit,
+)
+from cirq.circuits.circuit_operation import CircuitOperation as CircuitOperation
+from cirq.circuits.frozen_circuit import FrozenCircuit as FrozenCircuit
+from cirq.circuits.insert_strategy import InsertStrategy as InsertStrategy
 
-from cirq.circuits.circuit import AbstractCircuit, Alignment, Circuit
-from cirq.circuits.circuit_operation import CircuitOperation
-from cirq.circuits.frozen_circuit import FrozenCircuit
-from cirq.circuits.insert_strategy import InsertStrategy
+from cirq.circuits.moment import Moment as Moment
 
-from cirq.circuits.moment import Moment
-
-from cirq.circuits.optimization_pass import PointOptimizer, PointOptimizationSummary
+from cirq.circuits.optimization_pass import (
+    PointOptimizer as PointOptimizer,
+    PointOptimizationSummary as PointOptimizationSummary,
+)

cirq/contrib/__init__.py

@@ -21,6 +21,6 @@
 from cirq.contrib import acquaintance
 from cirq.contrib import graph_device
 from cirq.contrib import quirk
-from cirq.contrib.qcircuit import circuit_to_latex_using_qcircuit
+from cirq.contrib.qcircuit import circuit_to_latex_using_qcircuit as circuit_to_latex_using_qcircuit
 from cirq.contrib import json
-from cirq.contrib.circuitdag import CircuitDag, Unique
+from cirq.contrib.circuitdag import CircuitDag as CircuitDag, Unique as Unique

cirq/contrib/acquaintance/__init__.py

@@ -13,55 +13,70 @@
 # limitations under the License.
 
 """Tools for creating and using acquaintance strategies."""
+from cirq.contrib.acquaintance.bipartite import (
+    BipartiteGraphType as BipartiteGraphType,
+    BipartiteSwapNetworkGate as BipartiteSwapNetworkGate,
+)
 
-from cirq.contrib.acquaintance.bipartite import BipartiteGraphType, BipartiteSwapNetworkGate
-
-from cirq.contrib.acquaintance.devices import get_acquaintance_size, UnconstrainedAcquaintanceDevice
+from cirq.contrib.acquaintance.devices import (
+    get_acquaintance_size as get_acquaintance_size,
+    UnconstrainedAcquaintanceDevice as UnconstrainedAcquaintanceDevice,
+)
 
 from cirq.contrib.acquaintance.executor import (
-    AcquaintanceOperation,
-    GreedyExecutionStrategy,
-    StrategyExecutorTransformer,
+    AcquaintanceOperation as AcquaintanceOperation,
+    GreedyExecutionStrategy as GreedyExecutionStrategy,
+    StrategyExecutorTransformer as StrategyExecutorTransformer,
 )
 
-from cirq.contrib.acquaintance.gates import acquaint, AcquaintanceOpportunityGate, SwapNetworkGate
+from cirq.contrib.acquaintance.gates import (
+    acquaint as acquaint,
+    AcquaintanceOpportunityGate as AcquaintanceOpportunityGate,
+    SwapNetworkGate as SwapNetworkGate,
+)
 
-from cirq.contrib.acquaintance.inspection_utils import get_logical_acquaintance_opportunities
+from cirq.contrib.acquaintance.inspection_utils import (
+    get_logical_acquaintance_opportunities as get_logical_acquaintance_opportunities,
+)
 
 from cirq.contrib.acquaintance.mutation_utils import (
-    expose_acquaintance_gates,
-    rectify_acquaintance_strategy,
-    replace_acquaintance_with_swap_network,
+    expose_acquaintance_gates as expose_acquaintance_gates,
+    rectify_acquaintance_strategy as rectify_acquaintance_strategy,
+    replace_acquaintance_with_swap_network as replace_acquaintance_with_swap_network,
 )
 
-from cirq.contrib.acquaintance.optimizers import remove_redundant_acquaintance_opportunities
+from cirq.contrib.acquaintance.optimizers import (
+    remove_redundant_acquaintance_opportunities as remove_redundant_acquaintance_opportunities,
+)
 
 from cirq.contrib.acquaintance.permutation import (
-    LinearPermutationGate,
-    PermutationGate,
-    SwapPermutationGate,
-    update_mapping,
-    get_logical_operations,
-    display_mapping,
-    return_to_initial_mapping,
-    uses_consistent_swap_gate,
-    EXPAND_PERMUTATION_GATES,
-    DECOMPOSE_PERMUTATION_GATES,
+    LinearPermutationGate as LinearPermutationGate,
+    PermutationGate as PermutationGate,
+    SwapPermutationGate as SwapPermutationGate,
+    update_mapping as update_mapping,
+    get_logical_operations as get_logical_operations,
+    display_mapping as display_mapping,
+    return_to_initial_mapping as return_to_initial_mapping,
+    uses_consistent_swap_gate as uses_consistent_swap_gate,
+    EXPAND_PERMUTATION_GATES as EXPAND_PERMUTATION_GATES,
+    DECOMPOSE_PERMUTATION_GATES as DECOMPOSE_PERMUTATION_GATES,
 )
 
-from cirq.contrib.acquaintance.shift import CircularShiftGate
+from cirq.contrib.acquaintance.shift import CircularShiftGate as CircularShiftGate
 
-from cirq.contrib.acquaintance.shift_swap_network import ShiftSwapNetworkGate
+from cirq.contrib.acquaintance.shift_swap_network import (
+    ShiftSwapNetworkGate as ShiftSwapNetworkGate,
+)
 
 from cirq.contrib.acquaintance.strategies import (
-    complete_acquaintance_strategy,
-    cubic_acquaintance_strategy,
-    quartic_paired_acquaintance_strategy,
+    complete_acquaintance_strategy as complete_acquaintance_strategy,
+    cubic_acquaintance_strategy as cubic_acquaintance_strategy,
+    quartic_paired_acquaintance_strategy as quartic_paired_acquaintance_strategy,
 )
 
 from cirq.contrib.acquaintance.topological_sort import (
-    is_topologically_sorted,
-    random_topological_sort,
+    is_topologically_sorted as is_topologically_sorted,
+    random_topological_sort as random_topological_sort,
 )
 
 from cirq.contrib.acquaintance import testing

cirq/contrib/acquaintance/strategies/__init__.py

@@ -14,6 +14,12 @@
 
 """Acquaintance strategies."""
 
-from cirq.contrib.acquaintance.strategies.complete import complete_acquaintance_strategy
-from cirq.contrib.acquaintance.strategies.cubic import cubic_acquaintance_strategy
-from cirq.contrib.acquaintance.strategies.quartic_paired import quartic_paired_acquaintance_strategy
+from cirq.contrib.acquaintance.strategies.complete import (
+    complete_acquaintance_strategy as complete_acquaintance_strategy,
+)
+from cirq.contrib.acquaintance.strategies.cubic import (
+    cubic_acquaintance_strategy as cubic_acquaintance_strategy,
+)
+from cirq.contrib.acquaintance.strategies.quartic_paired import (
+    quartic_paired_acquaintance_strategy as quartic_paired_acquaintance_strategy,
+)

cirq/contrib/bayesian_network/__init__.py

@@ -12,4 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from cirq.contrib.bayesian_network.bayesian_network_gate import BayesianNetworkGate
+from cirq.contrib.bayesian_network.bayesian_network_gate import (
+    BayesianNetworkGate as BayesianNetworkGate,
+)

cirq/contrib/circuitdag/__init__.py

@@ -14,4 +14,4 @@
 
 """Tools for representing a Circuit as a directed acyclic graph."""
 
-from cirq.contrib.circuitdag.circuit_dag import CircuitDag, Unique
+from cirq.contrib.circuitdag.circuit_dag import CircuitDag as CircuitDag, Unique as Unique

cirq/contrib/circuitdag/circuit_dag.py

@@ -11,16 +11,14 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Any, Callable, Dict, Generic, Iterator, TypeVar, cast, TYPE_CHECKING
+
+from typing import Any, Callable, Dict, Generic, Iterator, TypeVar, cast
 
 import functools
 import networkx
 
+import cirq
 from cirq import ops
-from cirq.circuits import circuit
-
-if TYPE_CHECKING:
-    import cirq
 
 T = TypeVar('T')
 
@@ -98,7 +96,7 @@ def make_node(op: 'cirq.Operation') -> Unique:
 
     @staticmethod
     def from_circuit(
-        circuit: circuit.Circuit,
+        circuit: cirq.Circuit,
         can_reorder: Callable[['cirq.Operation', 'cirq.Operation'], bool] = _disjoint_qubits,
     ) -> 'CircuitDag':
         return CircuitDag.from_ops(circuit.all_operations(), can_reorder=can_reorder)
@@ -179,8 +177,8 @@ def all_operations(self) -> Iterator['cirq.Operation']:
     def all_qubits(self):
         return frozenset(q for node in self.nodes for q in node.val.qubits)
 
-    def to_circuit(self) -> circuit.Circuit:
-        return circuit.Circuit(self.all_operations(), strategy=circuit.InsertStrategy.EARLIEST)
+    def to_circuit(self) -> cirq.Circuit:
+        return cirq.Circuit(self.all_operations(), strategy=cirq.InsertStrategy.EARLIEST)
 
     def findall_nodes_until_blocked(
         self, is_blocker: Callable[['cirq.Operation'], bool]

cirq/contrib/graph_device/__init__.py

@@ -14,17 +14,17 @@
 
 """Tools for representing a device as an edge-labelled graph."""
 
-from cirq.contrib.graph_device.hypergraph import UndirectedHypergraph
+from cirq.contrib.graph_device.hypergraph import UndirectedHypergraph as UndirectedHypergraph
 
 from cirq.contrib.graph_device.graph_device import (
-    is_undirected_device_graph,
-    is_crosstalk_graph,
-    FixedDurationUndirectedGraphDeviceEdge,
-    UndirectedGraphDevice,
-    UnconstrainedUndirectedGraphDeviceEdge,
+    is_undirected_device_graph as is_undirected_device_graph,
+    is_crosstalk_graph as is_crosstalk_graph,
+    FixedDurationUndirectedGraphDeviceEdge as FixedDurationUndirectedGraphDeviceEdge,
+    UndirectedGraphDevice as UndirectedGraphDevice,
+    UnconstrainedUndirectedGraphDeviceEdge as UnconstrainedUndirectedGraphDeviceEdge,
 )
 
 from cirq.contrib.graph_device.uniform_graph_device import (
-    uniform_undirected_graph_device,
-    uniform_undirected_linear_device,
+    uniform_undirected_graph_device as uniform_undirected_graph_device,
+    uniform_undirected_linear_device as uniform_undirected_linear_device,
 )

cirq/contrib/noise_models/__init__.py

@@ -11,11 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 from cirq.contrib.noise_models.noise_models import (
-    DepolarizingNoiseModel,
-    ReadoutNoiseModel,
-    DampedReadoutNoiseModel,
-    DepolarizingWithReadoutNoiseModel,
-    DepolarizingWithDampedReadoutNoiseModel,
+    DepolarizingNoiseModel as DepolarizingNoiseModel,
+    ReadoutNoiseModel as ReadoutNoiseModel,
+    DampedReadoutNoiseModel as DampedReadoutNoiseModel,
+    DepolarizingWithReadoutNoiseModel as DepolarizingWithReadoutNoiseModel,
+    DepolarizingWithDampedReadoutNoiseModel as DepolarizingWithDampedReadoutNoiseModel,
 )

cirq/contrib/paulistring/__init__.py

@@ -14,23 +14,31 @@
 
 """Methods related to optimizing and transforming PauliStrings."""
 
-from cirq.contrib.paulistring.clifford_target_gateset import CliffordTargetGateset
+from cirq.contrib.paulistring.clifford_target_gateset import (
+    CliffordTargetGateset as CliffordTargetGateset,
+)
 
 from cirq.contrib.paulistring.separate import (
-    convert_and_separate_circuit,
-    pauli_string_half,
-    regular_half,
+    convert_and_separate_circuit as convert_and_separate_circuit,
+    pauli_string_half as pauli_string_half,
+    regular_half as regular_half,
 )
 
 from cirq.contrib.paulistring.pauli_string_dag import (
-    pauli_string_dag_from_circuit,
-    pauli_string_reorder_pred,
+    pauli_string_dag_from_circuit as pauli_string_dag_from_circuit,
+    pauli_string_reorder_pred as pauli_string_reorder_pred,
 )
 
-from cirq.contrib.paulistring.recombine import move_pauli_strings_into_circuit
+from cirq.contrib.paulistring.recombine import (
+    move_pauli_strings_into_circuit as move_pauli_strings_into_circuit,
+)
 
-from cirq.contrib.paulistring.pauli_string_optimize import pauli_string_optimized_circuit
+from cirq.contrib.paulistring.pauli_string_optimize import (
+    pauli_string_optimized_circuit as pauli_string_optimized_circuit,
+)
 
-from cirq.contrib.paulistring.clifford_optimize import clifford_optimized_circuit
+from cirq.contrib.paulistring.clifford_optimize import (
+    clifford_optimized_circuit as clifford_optimized_circuit,
+)
 
-from cirq.contrib.paulistring.optimize import optimized_circuit
+from cirq.contrib.paulistring.optimize import optimized_circuit as optimized_circuit

cirq/contrib/qasm_import/__init__.py

@@ -12,5 +12,5 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from cirq.contrib.qasm_import.exception import QasmException
-from cirq.contrib.qasm_import.qasm import circuit_from_qasm
+from cirq.contrib.qasm_import.exception import QasmException as QasmException
+from cirq.contrib.qasm_import.qasm import circuit_from_qasm as circuit_from_qasm

cirq/contrib/qcircuit/__init__.py

@@ -14,10 +14,12 @@
 
 """Converts cirq circuits into latex using qcircuit."""
 
-from cirq.contrib.qcircuit.qcircuit_diagram import circuit_to_latex_using_qcircuit
+from cirq.contrib.qcircuit.qcircuit_diagram import (
+    circuit_to_latex_using_qcircuit as circuit_to_latex_using_qcircuit,
+)
 
 from cirq.contrib.qcircuit.qcircuit_diagram_info import (
-    escape_text_for_latex,
-    get_multigate_parameters,
-    get_qcircuit_diagram_info,
+    escape_text_for_latex as escape_text_for_latex,
+    get_multigate_parameters as get_multigate_parameters,
+    get_qcircuit_diagram_info as get_qcircuit_diagram_info,
 )

cirq/contrib/quantum_volume/__init__.py

@@ -14,11 +14,11 @@
 """Utilities running the Quantum Volume benchmark on devices"""
 
 from cirq.contrib.quantum_volume.quantum_volume import (
-    generate_model_circuit,
-    compute_heavy_set,
-    sample_heavy_set,
-    compile_circuit,
-    calculate_quantum_volume,
-    QuantumVolumeResult,
-    CompilationResult,
+    generate_model_circuit as generate_model_circuit,
+    compute_heavy_set as compute_heavy_set,
+    sample_heavy_set as sample_heavy_set,
+    compile_circuit as compile_circuit,
+    calculate_quantum_volume as calculate_quantum_volume,
+    QuantumVolumeResult as QuantumVolumeResult,
+    CompilationResult as CompilationResult,
 )

cirq/contrib/quimb/__init__.py

@@ -1,23 +1,26 @@
 # pylint: disable=wrong-or-nonexistent-copyright-notice
 from cirq.contrib.quimb.state_vector import (
-    circuit_for_expectation_value,
-    tensor_expectation_value,
-    circuit_to_tensors,
-    tensor_state_vector,
-    tensor_unitary,
+    circuit_for_expectation_value as circuit_for_expectation_value,
+    tensor_expectation_value as tensor_expectation_value,
+    circuit_to_tensors as circuit_to_tensors,
+    tensor_state_vector as tensor_state_vector,
+    tensor_unitary as tensor_unitary,
 )
 
 from cirq.contrib.quimb.density_matrix import (
-    tensor_density_matrix,
-    circuit_to_density_matrix_tensors,
+    tensor_density_matrix as tensor_density_matrix,
+    circuit_to_density_matrix_tensors as circuit_to_density_matrix_tensors,
 )
 
-from cirq.contrib.quimb.grid_circuits import simplify_expectation_value_circuit, get_grid_moments
+from cirq.contrib.quimb.grid_circuits import (
+    simplify_expectation_value_circuit as simplify_expectation_value_circuit,
+    get_grid_moments as get_grid_moments,
+)
 
 from cirq.contrib.quimb.mps_simulator import (
-    MPSOptions,
-    MPSSimulator,
-    MPSSimulatorStepResult,
-    MPSState,
-    MPSTrialResult,
+    MPSOptions as MPSOptions,
+    MPSSimulator as MPSSimulator,
+    MPSSimulatorStepResult as MPSSimulatorStepResult,
+    MPSState as MPSState,
+    MPSTrialResult as MPSTrialResult,
 )

cirq/contrib/quirk/__init__.py

@@ -14,4 +14,4 @@
 
 """Converts cirq circuits into quirk circuits."""
 
-from cirq.contrib.quirk.export_to_quirk import circuit_to_quirk_url
+from cirq.contrib.quirk.export_to_quirk import circuit_to_quirk_url as circuit_to_quirk_url