ref: Unsample on sampler exception

sentry_sdk/profiler/transaction_profiler.py

@@ -290,12 +290,11 @@ def _set_initial_sampling_decision(
                 sample_rate = options["profiles_sampler"](sampling_context)
             except Exception:
                 logger.warning(
-                    "[Profiling] profiles_sampler raised; falling back to profiles_sample_rate",
+                    "[Profiling] profiles_sampler raised; unsampling profile",
                     exc_info=True,
                 )
-                sample_rate = options["profiles_sample_rate"]
-                if sample_rate is None:
-                    sample_rate = options["_experiments"].get("profiles_sample_rate")
+                self.sampled = False
+                return
         elif options["profiles_sample_rate"] is not None:
             sample_rate = options["profiles_sample_rate"]
         else:

sentry_sdk/tracing.py

@@ -1217,14 +1217,11 @@ def _set_initial_sampling_decision(
                 sample_rate = client.options["traces_sampler"](sampling_context)
             except Exception:
                 logger.warning(
-                    "[Tracing] traces_sampler raised; falling back to parent sample rate or traces_sample_rate",
+                    "[Tracing] traces_sampler raised; unsampling trace",
                     exc_info=True,
                 )
-                sample_rate = (
-                    sampling_context["parent_sampled"]
-                    if sampling_context["parent_sampled"] is not None
-                    else client.options["traces_sample_rate"]
-                )
+                self.sampled = False
+                return
         else:
             sample_rate = (
                 sampling_context["parent_sampled"]

sentry_sdk/tracing_utils.py

@@ -1702,13 +1702,10 @@ def _make_sampling_decision(
             sample_rate = client.options["traces_sampler"](sampling_context)
         except Exception:
             logger.warning(
-                "[Tracing] traces_sampler raised; falling back to parent sample rate or traces_sample_rate",
+                "[Tracing] traces_sampler raised; unsampling trace",
                 exc_info=True,
             )
-            if propagation_context.parent_sampled is not None:
-                sample_rate = propagation_context.parent_sampled
-            else:
-                sample_rate = client.options["traces_sample_rate"]
+            return False, None, None, "callback_error"
     else:
         if propagation_context.parent_sampled is not None:
             sample_rate = propagation_context.parent_sampled

tests/profiler/test_transaction_profiler.py

@@ -238,7 +238,7 @@ def test_profiles_sampler(
 
 @pytest.mark.tests_internal_exceptions
 @mock.patch("sentry_sdk.profiler.transaction_profiler.PROFILE_MINIMUM_SAMPLES", 0)
-def test_profiles_sampler_exception_falls_back_to_profiles_sample_rate(
+def test_profiles_sampler_exception_unsamples(
     sentry_init,
     capture_envelopes,
     teardown_profiling,
@@ -263,8 +263,7 @@ def bad_sampler(sampling_context):
             items[item.type].append(item)
 
     assert len(items["transaction"]) == 1
-    # Falls back to profiles_sample_rate=1.0, so profile should be sent
-    assert len(items["profile"]) == 1
+    assert len(items["profile"]) == 0
 
 
 def test_minimum_unique_samples_required(

tests/tracing/test_sampling.py

@@ -198,117 +198,17 @@ def test_tolerates_traces_sampler_returning_a_boolean_span_streaming(
         assert span.sampled is traces_sampler_return_value
 
 
-@pytest.mark.parametrize(
-    "traces_sample_rate,expected_decision",
-    [(0.0, False), (0.25, False), (0.75, True), (1.00, True)],
-)
-def test_traces_sampler_raising_falls_back_to_traces_sample_rate(
-    sentry_init,
-    traces_sample_rate,
-    expected_decision,
-):
+def test_traces_sampler_raising_unsamples(sentry_init):
     sentry_init(
         traces_sampler=mock.Mock(side_effect=ValueError("boom")),
-        traces_sample_rate=traces_sample_rate,
+        traces_sample_rate=1.0,
     )
 
     baggage = Baggage(sentry_items={"sample_rand": "0.500000"})
     transaction = start_transaction(name="dogpark", baggage=baggage)
-    assert transaction.sampled is expected_decision
-
-
-@pytest.mark.parametrize("parent_sampling_decision", [True, False])
-def test_traces_sampler_raising_falls_back_to_parent_sampling_decision(
-    sentry_init, parent_sampling_decision
-):
-    # set traces_sample_rate to produce the opposite of the parent decision,
-    # to prove the parent's decision takes precedence in the fallback
-    sentry_init(
-        traces_sampler=mock.Mock(side_effect=ValueError("boom")),
-        traces_sample_rate=0.0 if parent_sampling_decision else 1.0,
-    )
-
-    baggage = Baggage(sentry_items={"sample_rand": "0.500000"})
-    transaction = start_transaction(
-        name="dogpark", baggage=baggage, parent_sampled=parent_sampling_decision
-    )
-    assert transaction.sampled is parent_sampling_decision
-
-
-@pytest.mark.parametrize(
-    "traces_sample_rate,expected_decision",
-    [(0.0, False), (0.25, False), (0.75, True), (1.00, True)],
-)
-def test_traces_sampler_raising_falls_back_to_traces_sample_rate_span_streaming(
-    sentry_init,
-    traces_sample_rate,
-    expected_decision,
-):
-    sentry_init(
-        traces_sampler=mock.Mock(side_effect=ValueError("boom")),
-        traces_sample_rate=traces_sample_rate,
-        trace_lifecycle="stream",
-    )
-
-    sentry_sdk.traces.continue_trace(
-        {
-            "sentry-trace": "0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331",
-            "baggage": "sentry-sample_rand=0.500000",
-        }
-    )
-
-    with sentry_sdk.traces.start_span(name="dogpark") as span:
-        assert span.sampled is expected_decision
-
-
-@pytest.mark.parametrize(
-    "traces_sample_rate,expected_decision",
-    [(0.0, False), (0.25, False), (0.75, True), (1.00, True)],
-)
-def test_traces_sampler_raising_no_incoming_trace_falls_back_to_traces_sample_rate_span_streaming(
-    sentry_init,
-    traces_sample_rate,
-    expected_decision,
-    monkeypatch,
-):
-    sentry_init(
-        traces_sampler=mock.Mock(side_effect=ValueError("boom")),
-        traces_sample_rate=traces_sample_rate,
-        trace_lifecycle="stream",
-    )
-
-    # no continue_trace, so no propagated sample_rand; make it deterministic
-    monkeypatch.setattr(
-        "sentry_sdk.tracing_utils._generate_sample_rand", lambda *a, **kw: 0.5
-    )
-
-    with sentry_sdk.traces.start_span(name="dogpark") as span:
-        assert span.sampled is expected_decision
-
-
-def test_traces_sampler_raising_no_incoming_trace_and_no_traces_sample_rate(
-    sentry_init,
-):
-    sentry_init(
-        traces_sampler=mock.Mock(side_effect=ValueError("boom")),
-    )
-
-    transaction = start_transaction(name="dogpark")
     assert transaction.sampled is False
 
 
-def test_traces_sampler_raising_no_incoming_trace_and_no_traces_sample_rate_span_streaming(
-    sentry_init,
-):
-    sentry_init(
-        traces_sampler=mock.Mock(side_effect=ValueError("boom")),
-        trace_lifecycle="stream",
-    )
-
-    with sentry_sdk.traces.start_span(name="dogpark") as span:
-        assert span.sampled is False
-
-
 @pytest.mark.parametrize("sampling_decision", [True, False])
 def test_only_captures_transaction_when_sampled_is_true(
     sentry_init, sampling_decision, capture_events

tests/tracing/test_span_streaming.py

@@ -565,7 +565,7 @@ def traces_sampler(sampling_context):
 
 
 @pytest.mark.tests_internal_exceptions
-def test_traces_sampler_exception_falls_back(sentry_init, capture_items):
+def test_traces_sampler_exception_unsamples(sentry_init, capture_items):
     def traces_sampler(sampling_context):
         raise ValueError("traces_sampler error")
 
@@ -580,11 +580,11 @@ def traces_sampler(sampling_context):
     with sentry_sdk.traces.start_span(name="test"):
         ...
 
-    sentry_sdk.get_client().flush()
+    sentry_sdk.flush()
+
     spans = [item.payload for item in items]
 
-    # Falls back to traces_sample_rate=1.0, so span should still be sent
-    assert len(spans) == 1
+    assert not spans
 
 
 def test_traces_sampler_called_once_per_segment(sentry_init):