[tracing] Assert that OTLP spans have full 128-bit trace IDs#6973
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…it_trace_id_consistent_across_spans to validate that implementations export all OTLP spans with the full 128-bit trace ID. This was identified as an issue in the libdatadog implementation
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# What does this PR do? This PR updates the conversion of DD spans to OTLP spans to ensure all spans receive the high 64 bits of the 128-bit trace ID. DD tracers set `_dd.p.tid` (high 64 bits of 128-bit trace ID) only on the chunk root per RFC #85 — the Datadog backend reconstructs the full 128-bit ID at ingest. The OTLP mapper previously only read the tag per span, so child spans were emitted with upper 64 bits zeroed and traces fragmented in pure-OTel backends. The approach determines the chunk-level `_dd.p.tid` once in `map_traces_to_otlp` and applies it to every span in the chunk. Per-span value still wins (forward-compat with tracers that propagate everywhere). Use `find_map` over the chunk so a malformed root tag falls back to the first parseable value in the chunk rather than poisoning the whole trace. # Motivation Performing end-to-end tests with dd-trace-py exporting OTLP spans surfaced this issue, which results in child spans recording different trace IDs than the local root spans. Notably, the only difference was that the high 64-bits of the 128-bit trace ID were zero'ed out. # Additional Notes A system-test to cover this scenario is being simultaneously added in DataDog/system-tests#6973 # How to test the change? Regression tests have been added to `libdd-trace-utils/src/otlp_encoder/mapper.rs`. Co-authored-by: zach.montoya <zach.montoya@datadoghq.com>
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Motivation
End-to-end testing identified that traces exported as OTLP by dd-trace-py had incorrect trace IDs. The HTTP server span had a 128-bit trace ID while its child spans had that same trace ID except the upper 64 bits were zeroed out. This test will ensure that we track and remediate this behavior across all languages.
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test/otel_test_tracing_otlp.py::Test_Otel_Tracing_OTLP::test_128bit_trace_id_consistent_across_spansto validate that implementations export all OTLP spans with the full 128-bit trace ID. This was identified as an issue in the libdatadog implementationWorkflow
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