Fix rust span pointer invalidation on inferred span serialization#3934
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Benchmarks [ tracer ]Benchmark execution time: 2026-05-28 14:54:41 Comparing candidate commit 6b5659e in PR branch Found 0 performance improvements and 0 performance regressions! Performance is the same for 194 metrics, 0 unstable metrics. |
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Motivation
ddog_SpanBytes *pointing into a RustVecand then recursively appended an inferred span into the sameVec, which can reallocate and move elements and thus invalidate the saved pointer.DD_TRACE_INFERRED_PROXY_SERVICES_ENABLEDtriggers inferred-span serialization into the same trace.Description
rust_span_index = ddog_get_trace_size(trace)and use it to determineis_first_spaninstead of querying size after append.rust_span = ddog_get_span(trace, rust_span_index)before any further dereferences or transfers.ext/serializer.cthat preserves existing behavior while avoiding dereferencing a potentially stale pointer.Testing
php -l ext/serializer.cto validate there are no syntax errors, and it succeeded.Codex Task