require make_testcase be passed frozen datas

Author: tybug

hypothesis-python/src/hypothesis/core.py

@@ -675,6 +675,7 @@ def execute_explicit_examples(state, wrapped_test, arguments, kwargs, original_s
                         "Falsifying example", "Falsifying explicit example", 1
                     )
 
+                empty_data.freeze()
                 tc = make_testcase(
                     run_start=state._start_timestamp,
                     property=state.test_identifier,
@@ -1302,6 +1303,7 @@ def _execute_once_for_engine(self, data: ConjectureData) -> None:
                     data._observability_args = {}
                     self._string_repr = "<backend failed to realize symbolic arguments>"
 
+                data.freeze()
                 tc = make_testcase(
                     run_start=self._start_timestamp,
                     property=self.test_identifier,
@@ -1498,6 +1500,7 @@ def run_engine(self):
                 # execute_once() will always raise either the expected error, or Flaky.
                 raise NotImplementedError("This should be unreachable")
             finally:
+                ran_example.freeze()
                 # log our observability line for the final failing example
                 tc = make_testcase(
                     run_start=self._start_timestamp,
@@ -1521,11 +1524,7 @@ def run_engine(self):
                         f"{reproduction_decorator(falsifying_example.choices)} "
                         "as a decorator on your test case"
                     )
-                # Mostly useful for ``find`` and ensuring that objects that
-                # hold on to a reference to ``data`` know that it's now been
-                # finished and they can't draw more data from it.
-                ran_example.freeze()  # pragma: no branch
-                # No branch is possible here because we never have an active exception.
+
         _raise_to_user(
             errors_to_report,
             self.settings,
@@ -2096,6 +2095,7 @@ def fuzz_one_input(
                     raise
                 finally:
                     if TESTCASE_CALLBACKS:
+                        data.freeze()
                         tc = make_testcase(
                             run_start=state._start_timestamp,
                             property=state.test_identifier,

hypothesis-python/src/hypothesis/internal/observability.py

@@ -265,6 +265,10 @@ def make_testcase(
     from hypothesis.core import reproduction_decorator
     from hypothesis.internal.conjecture.data import Status
 
+    # We should only be sending observability reports for datas that have finished
+    # being modified.
+    assert data.frozen
+
     if status_reason is not None:
         pass
     elif data.interesting_origin: