exporter/b3: Fix B3 propagator to not crash work with DefaultSpan (#1148)

Author: owais

opentelemetry-sdk/src/opentelemetry/sdk/trace/propagation/b3_format.py

@@ -140,21 +140,23 @@ def inject(
     ) -> None:
         span = trace.get_current_span(context=context)
 
-        if span.get_context() == trace.INVALID_SPAN_CONTEXT:
+        span_context = span.get_context()
+        if span_context == trace.INVALID_SPAN_CONTEXT:
             return
 
-        sampled = (trace.TraceFlags.SAMPLED & span.context.trace_flags) != 0
+        sampled = (trace.TraceFlags.SAMPLED & span_context.trace_flags) != 0
         set_in_carrier(
-            carrier, self.TRACE_ID_KEY, format_trace_id(span.context.trace_id),
+            carrier, self.TRACE_ID_KEY, format_trace_id(span_context.trace_id),
         )
         set_in_carrier(
-            carrier, self.SPAN_ID_KEY, format_span_id(span.context.span_id)
+            carrier, self.SPAN_ID_KEY, format_span_id(span_context.span_id)
         )
-        if span.parent is not None:
+        span_parent = getattr(span, "parent", None)
+        if span_parent is not None:
             set_in_carrier(
                 carrier,
                 self.PARENT_SPAN_ID_KEY,
-                format_span_id(span.parent.span_id),
+                format_span_id(span_parent.span_id),
             )
         set_in_carrier(carrier, self.SAMPLED_KEY, "1" if sampled else "0")
 

opentelemetry-sdk/tests/trace/propagation/test_b3_format.py

@@ -307,3 +307,16 @@ def test_inject_empty_context():
         new_carrier = {}
         FORMAT.inject(dict.__setitem__, new_carrier, get_current())
         assert len(new_carrier) == 0
+
+    @staticmethod
+    def test_default_span():
+        """Make sure propagator does not crash when working with DefaultSpan"""
+
+        def getter(carrier, key):
+            return carrier.get(key, None)
+
+        def setter(carrier, key, value):
+            carrier[key] = value
+
+        ctx = FORMAT.extract(getter, {})
+        FORMAT.inject(setter, {}, ctx)