Fix rust span pointer invalidation on inferred span serialization

bwoebi · bwoebi · commit 27ae4afa0abe · 2026-05-28T15:34:46.000+02:00
diff --git a/ext/serializer.c b/ext/serializer.c
@@ -1548,7 +1548,8 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
         }
     }
 
-    bool is_first_span = ddog_get_trace_size(trace) == 0;
+    uintptr_t rust_span_index = ddog_get_trace_size(trace);
+    bool is_first_span = rust_span_index == 0;
     ddog_SpanBytes *rust_span = ddog_trace_new_span(trace);
 
     ddog_set_span_trace_id(rust_span, span->root->trace_id.low);
@@ -1834,6 +1835,7 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
 
     if (inferred_span) {
         ddog_SpanBytes *serialized_inferred_span = ddtrace_serialize_span_to_rust_span(inferred_span, trace);
+        rust_span = ddog_get_span(trace, rust_span_index);
 
         transfer_metrics_data(rust_span, serialized_inferred_span, "_dd.agent_psr", true);
         transfer_metrics_data(rust_span, serialized_inferred_span, "_dd.rule_psr", true);

Original file line number	Diff line number	Diff line change
`@@ -1548,7 +1548,8 @@ ddog_SpanBytes ddtrace_serialize_span_to_rust_span(ddtrace_span_data span, ddo`
`1548`	`1548`	`}`
`1549`	`1549`	`}`
`1550`	`1550`
`1551`		`- bool is_first_span = ddog_get_trace_size(trace) == 0;`
	`1551`	`+ uintptr_t rust_span_index = ddog_get_trace_size(trace);`
	`1552`	`+ bool is_first_span = rust_span_index == 0;`
`1552`	`1553`	`ddog_SpanBytes *rust_span = ddog_trace_new_span(trace);`
`1553`	`1554`
`1554`	`1555`	`ddog_set_span_trace_id(rust_span, span->root->trace_id.low);`
`@@ -1834,6 +1835,7 @@ ddog_SpanBytes ddtrace_serialize_span_to_rust_span(ddtrace_span_data span, ddo`
`1834`	`1835`
`1835`	`1836`	`if (inferred_span) {`
`1836`	`1837`	`ddog_SpanBytes *serialized_inferred_span = ddtrace_serialize_span_to_rust_span(inferred_span, trace);`
	`1838`	`+ rust_span = ddog_get_span(trace, rust_span_index);`
`1837`	`1839`
`1838`	`1840`	`transfer_metrics_data(rust_span, serialized_inferred_span, "_dd.agent_psr", true);`
`1839`	`1841`	`transfer_metrics_data(rust_span, serialized_inferred_span, "_dd.rule_psr", true);`