fix: prevent shared mutable defaults for span attributes and events

src/instana/span/readable_span.py

@@ -53,8 +53,8 @@ def __init__(
         parent_id: Optional[str] = None,
         start_time: Optional[int] = None,
         end_time: Optional[int] = None,
-        attributes: types.Attributes = {},
-        events: Sequence[Event] = [],
+        attributes: Optional[types.Attributes] = None,
+        events: Optional[Sequence[Event]] = None,
         status: Optional[Status] = Status(StatusCode.UNSET),
         stack: Optional[List] = None,
         kind: SpanKind = SpanKind.INTERNAL,
@@ -68,8 +68,8 @@ def __init__(
             if self._start_time and self._end_time
             else None
         )
-        self._attributes = attributes if attributes else {}
-        self._events = events
+        self._attributes = dict(attributes) if attributes is not None else {}
+        self._events = list(events) if events is not None else []
         self._parent_id = parent_id
         self._status = status
         self.stack = stack

src/instana/span/span.py

@@ -50,8 +50,8 @@ def __init__(
         parent_id: Optional[str] = None,
         start_time: Optional[int] = None,
         end_time: Optional[int] = None,
-        attributes: types.Attributes = {},
-        events: Sequence[Event] = [],
+        attributes: Optional[types.Attributes] = None,
+        events: Optional[Sequence[Event]] = None,
         status: Optional[Status] = Status(StatusCode.UNSET),
         kind: SpanKind = SpanKind.INTERNAL,
     ) -> None:

tests/span/test_span.py

@@ -21,8 +21,6 @@ class TestSpan:
     def _resource(self) -> Generator[None, None, None]:
         self.span = None
         yield
-        if isinstance(self.span, InstanaSpan):
-            self.span.events.clear()
 
     def test_span_default(
         self,
@@ -928,3 +926,31 @@ def test_span_duration(
         assert isinstance(self.span.duration, int)
         assert self.span.duration > 0
         assert self.span.duration == (timestamp_end - self.span.start_time)
+
+    def test_spans_do_not_share_events_list(
+        self,
+        span_context: SpanContext,
+        span_processor: StanRecorder,
+    ) -> None:
+        span_a = InstanaSpan("span-a", span_context, span_processor)
+        span_b = InstanaSpan("span-b", span_context, span_processor)
+
+        span_a.add_event(name="event-a", attributes={"message": "msg"})
+
+        assert len(span_a.events) == 1
+        assert len(span_b.events) == 0
+        assert span_a.events is not span_b.events
+
+    def test_spans_do_not_share_attributes(
+        self,
+        span_context: SpanContext,
+        span_processor: StanRecorder,
+    ) -> None:
+        span_a = InstanaSpan("span-a", span_context, span_processor)
+        span_b = InstanaSpan("span-b", span_context, span_processor)
+
+        span_a.set_attribute("key_a", "val_a")
+
+        assert "key_a" in span_a.attributes
+        assert "key_a" not in span_b.attributes
+        assert span_a.attributes is not span_b.attributes

tests/span/test_span_stack_trace.py

@@ -19,8 +19,6 @@ class TestSpanStackTrace:
     def _resource(self) -> Generator[None, None, None]:
         self.span = None
         yield
-        if isinstance(self.span, InstanaSpan):
-            self.span.events.clear()
 
     def test_add_stack_hard_limit(
         self,