don't drop extract contexts lacking trace_id

ddtrace/contrib/trace_utils.py

@@ -565,7 +565,7 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
         context = HTTPPropagator.extract(request_headers)
 
         # Only need to activate the new context if something was propagated
-        if not context.trace_id:
+        if not context.trace_id or context._baggage:
             return None
 
         # Do not reactivate a context with the same trace id
@@ -577,7 +577,7 @@ def activate_distributed_headers(tracer, int_config=None, request_headers=None,
         #     app = Flask(__name__)  # Traced via Flask instrumentation
         #     app = DDWSGIMiddleware(app)  # Extra layer on top for WSGI
         current_context = tracer.current_trace_context()
-        if current_context and current_context.trace_id == context.trace_id:
+        if current_context and current_context.trace_id and current_context.trace_id == context.trace_id:
             log.debug(
                 "will not activate extracted Context(trace_id=%r, span_id=%r), a context with that trace id is already active",  # noqa: E501
                 context.trace_id,

tests/tracer/test_propagation.py

@@ -2494,14 +2494,14 @@ def test_propagation_extract_w_config(
         overrides["_propagation_style_extract"] = styles
     if extract_behavior is not None:
         overrides["_propagation_behavior_extract"] = extract_behavior
-        with override_global_config(overrides):
-            context = HTTPPropagator.extract(headers)
-            if not expected_context.get("tracestate"):
-                assert context == Context(**expected_context)
-            else:
-                copied_expectation = expected_context.copy()
-                tracestate = copied_expectation.pop("tracestate")
-                assert context == Context(**copied_expectation, meta={"tracestate": tracestate})
+    with override_global_config(overrides):
+        context = HTTPPropagator.extract(headers)
+        if not expected_context.get("tracestate"):
+            assert context == Context(**expected_context)
+        else:
+            copied_expectation = expected_context.copy()
+            tracestate = copied_expectation.pop("tracestate")
+            assert context == Context(**copied_expectation, meta={"tracestate": tracestate})
 
 
 EXTRACT_OVERRIDE_FIXTURES = [