fix(tracing): avoid crash on non-hex trace_context IDs

langfuse/_client/client.py

@@ -1670,22 +1670,32 @@ def create_event(
     def _create_remote_parent_span(
         self, *, trace_id: str, parent_span_id: Optional[str]
     ) -> Any:
-        if not self._is_valid_trace_id(trace_id):
-            langfuse_logger.warning(
-                f"Passed trace ID '{trace_id}' is not a valid 32 lowercase hex char Langfuse trace id. Ignoring trace ID."
-            )
-
-        if parent_span_id and not self._is_valid_span_id(parent_span_id):
+        try:
+            int_trace_id = int(trace_id, 16)
+            if not self._is_valid_trace_id(trace_id):
+                langfuse_logger.warning(
+                    f"Passed trace ID '{trace_id}' is not a standard 32 lowercase hex char Langfuse trace ID. It will be normalized to a standard OpenTelemetry trace ID format."
+                )
+        except (ValueError, TypeError):
             langfuse_logger.warning(
-                f"Passed span ID '{parent_span_id}' is not a valid 16 lowercase hex char Langfuse span id. Ignoring parent span ID."
+                f"Passed trace ID '{trace_id}' is not parseable as a hex trace ID. Ignoring it and generating a random trace ID instead."
             )
+            int_trace_id = RandomIdGenerator().generate_trace_id()
 
-        int_trace_id = int(trace_id, 16)
-        int_parent_span_id = (
-            int(parent_span_id, 16)
-            if parent_span_id
-            else RandomIdGenerator().generate_span_id()
-        )
+        if parent_span_id:
+            try:
+                int_parent_span_id = int(parent_span_id, 16)
+                if not self._is_valid_span_id(parent_span_id):
+                    langfuse_logger.warning(
+                        f"Passed span ID '{parent_span_id}' is not a standard 16 lowercase hex char Langfuse span ID. It will be normalized."
+                    )
+            except (ValueError, TypeError):
+                langfuse_logger.warning(
+                    f"Passed span ID '{parent_span_id}' is not parseable as a hex span ID. Ignoring it and generating a random span ID instead."
+                )
+                int_parent_span_id = RandomIdGenerator().generate_span_id()
+        else:
+            int_parent_span_id = RandomIdGenerator().generate_span_id()
 
         span_context = otel_trace_api.SpanContext(
             trace_id=int_trace_id,

tests/unit/test_otel.py

@@ -884,6 +884,48 @@ def test_custom_parent_span_id(self, langfuse_client, memory_exporter):
         assert spans[0]["trace_id"] == trace_id
         assert spans[0]["attributes"][LangfuseOtelSpanAttributes.AS_ROOT] is True
 
+    def test_non_hex_trace_id_does_not_crash(self, langfuse_client, memory_exporter):
+        """A non-hex trace ID must not raise; it falls back to a random trace ID."""
+        # Previously ``int(trace_id, 16)`` raised ValueError for non-hex IDs even
+        # though the warning claimed the ID would be ignored.
+        remote_parent_span = langfuse_client._create_remote_parent_span(
+            trace_id="my-trace-123", parent_span_id=None
+        )
+
+        span_context = remote_parent_span.get_span_context()
+        # 128-bit trace ID -> non-zero and within range
+        assert 0 < span_context.trace_id < 2**128
+        assert 0 < span_context.span_id < 2**64
+
+    def test_non_hex_parent_span_id_does_not_crash(
+        self, langfuse_client, memory_exporter
+    ):
+        """A non-hex parent span ID must not raise; it falls back to a random span ID."""
+        remote_parent_span = langfuse_client._create_remote_parent_span(
+            trace_id="abcdef1234567890abcdef1234567890",
+            parent_span_id="not-a-hex-span",
+        )
+
+        span_context = remote_parent_span.get_span_context()
+        assert span_context.trace_id == int("abcdef1234567890abcdef1234567890", 16)
+        assert 0 < span_context.span_id < 2**64
+
+    def test_parseable_non_standard_trace_id_is_preserved(
+        self, langfuse_client, memory_exporter
+    ):
+        """A hex but non-32-char trace ID stays usable (no regression, no fallback)."""
+        # 31 hex chars: parseable as hex, just not zero-padded to 32.
+        non_standard_trace_id = "1ab" + "0" * 28  # 31 chars
+        assert len(non_standard_trace_id) == 31
+
+        remote_parent_span = langfuse_client._create_remote_parent_span(
+            trace_id=non_standard_trace_id, parent_span_id=None
+        )
+
+        span_context = remote_parent_span.get_span_context()
+        # The integer is derived directly from the passed hex, not randomized.
+        assert span_context.trace_id == int(non_standard_trace_id, 16)
+
     def test_multiple_generations_in_trace(self, langfuse_client, memory_exporter):
         """Test creating multiple generation spans within the same trace."""
         # Create a trace with multiple generation spans