fix(tracing): Fix race condition between finish and start_child (#1203)

Author: kamilogorek

sentry_sdk/tracing.py

@@ -586,7 +586,7 @@ def finish(self, hub=None):
         # recorder -> span -> containing transaction (which is where we started)
         # before either the spans or the transaction goes out of scope and has
         # to be garbage collected
-        del self._span_recorder
+        self._span_recorder = None
 
         return hub.capture_event(
             {

tests/tracing/test_integration_tests.py

@@ -10,6 +10,7 @@
     start_span,
     start_transaction,
 )
+from sentry_sdk.transport import Transport
 from sentry_sdk.tracing import Transaction
 
 
@@ -147,3 +148,22 @@ def before_send(event, hint):
         pass
 
     assert len(events) == 1
+
+
+def test_start_span_after_finish(sentry_init, capture_events):
+    class CustomTransport(Transport):
+        def capture_envelope(self, envelope):
+            pass
+
+        def capture_event(self, event):
+            start_span(op="toolate", description="justdont")
+            pass
+
+    sentry_init(traces_sample_rate=1, transport=CustomTransport())
+    events = capture_events()
+
+    with start_transaction(name="hi"):
+        with start_span(op="bar", description="bardesc"):
+            pass
+
+    assert len(events) == 1