Fix pickle deserialization of ExperimentData (qiskit-community#1326)

Previously, `ExperimentData` objects could be serialized and
deserialized using Python's `pickle` module, but deserialized objects
were not completely restored and an exception would be raised when doing
some operations like running analysis on the restored object.

Author: wshanks

qiskit_experiments/framework/experiment_data.py

@@ -197,7 +197,7 @@ def _repr_svg_(self):
         return None
 
 
-FigureT = Union[str, bytes, MatplotlibFigure, FigureData]
+FigureType = Union[str, bytes, MatplotlibFigure, FigureData]
 
 
 class ExperimentData:
@@ -1142,7 +1142,7 @@ def data(
     @do_auto_save
     def add_figures(
         self,
-        figures: Union[FigureT, List[FigureT]],
+        figures: Union[FigureType, List[FigureType]],
         figure_names: Optional[Union[str, List[str]]] = None,
         overwrite: bool = False,
         save_figure: Optional[bool] = None,
@@ -2551,6 +2551,7 @@ def __setstate__(self, state):
         self._job_futures = ThreadSafeOrderedDict()
         self._analysis_futures = ThreadSafeOrderedDict()
         self._analysis_executor = futures.ThreadPoolExecutor(max_workers=1)
+        self._monitor_executor = futures.ThreadPoolExecutor()
 
     def __str__(self):
         line = 51 * "-"

releasenotes/notes/exp-data-pickle-61511b6e926e3198.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Fixed :mod:`pickle` deserialization of :class:`.ExperimentData` objects.
+    Previously, :class:`.ExperimentData` objects could be serialized and
+    deserialized using Python's ``pickle`` module, but deserialized objects
+    were not completely restored and an exception would be raised when doing
+    some operations like running analysis on the restored object. See `#1326
+    <https://github.com/Qiskit-Extensions/qiskit-experiments/pull/1326/files>`__.

test/extended_equality.py

@@ -249,7 +249,6 @@ def _check_service_analysis_results(
             "value",
             "extra",
             "device_components",
-            "result_id",
             "experiment_id",
             "chisq",
             "quality",
@@ -295,9 +294,36 @@ def _check_result_table(
     **kwargs,
 ):
     """Check equality of data frame which may involve Qiskit Experiments class value."""
+    table1 = data1.copy().to_dict(orient="index")
+    table2 = data2.copy().to_dict(orient="index")
+    for table in (table1, table2):
+        for result in table.values():
+            result.pop("created_time")
+            # Must ignore result ids because they are internally generated with
+            # random values by the ExperimentData wrapping object.
+            result.pop("result_id")
+    # Keys of the dict are based on the result ids so they must be ignored
+    # as well. Try to sort entries so equivalent entries will be in the same
+    # order.
+    table1 = sorted(
+        table1.values(),
+        key=lambda x: (
+            x["name"],
+            () if x["components"] is None else tuple(repr(d) for d in x["components"]),
+            x["value"],
+        ),
+    )
+    table2 = sorted(
+        table2.values(),
+        key=lambda x: (
+            x["name"],
+            () if x["components"] is None else tuple(repr(d) for d in x["components"]),
+            x["value"],
+        ),
+    )
     return is_equivalent(
-        data1.copy().to_dict(orient="index"),
-        data2.copy().to_dict(orient="index"),
+        table1,
+        table2,
         **kwargs,
     )
 

test/framework/test_framework.py

@@ -12,6 +12,7 @@
 
 """Tests for base experiment framework."""
 
+import pickle
 from test.fake_experiment import FakeExperiment, FakeAnalysis
 from test.base import QiskitExperimentsTestCase
 from itertools import product
@@ -127,6 +128,22 @@ def circuits(self):
                 num_jobs += 1
         self.assertEqual(len(job_ids), num_jobs)
 
+    def test_run_analysis_experiment_data_pickle_roundtrip(self):
+        """Test running analysis on ExperimentData after pickle roundtrip"""
+        analysis = FakeAnalysis()
+        expdata1 = ExperimentData()
+        # Set physical qubit for more complete comparison
+        expdata1.metadata["physical_qubits"] = (1,)
+        expdata1 = analysis.run(expdata1, seed=54321)
+        self.assertExperimentDone(expdata1)
+
+        expdata2 = ExperimentData(experiment_id=expdata1.experiment_id)
+        expdata2.metadata["physical_qubits"] = (1,)
+        expdata2 = pickle.loads(pickle.dumps(expdata2))
+        expdata2 = analysis.run(expdata2, replace_results=True, seed=54321)
+        self.assertExperimentDone(expdata2)
+        self.assertEqualExtended(expdata1, expdata2)
+
     def test_analysis_replace_results_true(self):
         """Test running analysis with replace_results=True"""
         analysis = FakeAnalysis()