Handle invalid span context more gracefully

Author: xrmx

opentelemetry-api/src/opentelemetry/trace/__init__.py

@@ -478,9 +478,12 @@ def start_span(
         if parent_span_context is not None and not isinstance(
             parent_span_context, SpanContext
         ):
-            raise TypeError(
-                "parent_span_context must be a SpanContext or None."
+            logger.warning(
+                "Invalid Span Context for %s: %s",
+                current_span,
+                parent_span_context,
             )
+            parent_span_context = None
 
         return NonRecordingSpan(context=parent_span_context)
 

opentelemetry-api/tests/test_implementation.py

@@ -128,8 +128,8 @@ def test_default_tracer_context_propagation_with_invalid_context(self):
         ctx = trace.set_span_in_context(
             RecordingSpan(context="invalid_context")  # type: ignore[reportArgumentType]
         )
-        with self.assertRaises(TypeError):
-            tracer.start_span("test", context=ctx)
+        with tracer.start_span("test", context=ctx) as span:
+            self.assertIsNone(span.get_span_context())
 
     def test_span(self):
         with self.assertRaises(TypeError):