refactor: move sampling interfaces to SpanData and Context by emmettbutler · Pull Request #19811 · DataDog/dd-trace-py

emmettbutler · 2026-08-21T17:59:54Z

This change removes a layering violation between Span and sampling.py by moving the relevant functionality to SpanData and Context.

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chatgpt-codex-connector · 2026-08-21T18:05:45Z

+                let copied = parent
+                    .bind(py)
+                    .call_method1("copy", (trace_id_obj, span_id_obj))?;


Release the SpanData borrow before dispatching Context.copy

When a public Context subclass overrides copy() and that method reads the current span (for example via a context provider), call_method1 executes the override while this getter's &mut self still holds the span's mutable PyO3 borrow. The reentrant span read then fails with an Already mutably borrowed/PanicException, whereas the previous Python getter invoked parent.copy() without holding such a borrow. Split this into immutable-read, Python-call, and mutable-write phases so valid custom contexts cannot crash when a child first reads .context.

AGENTS.md reference: AGENTS.md:L11-L11

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chatgpt-codex-connector · 2026-08-21T18:05:45Z

+    # `context`/`_context` (lazy build of this span's trace Context, cached on
+    # first read) are implemented natively on `SpanData` and inherited here.


Preserve context in the rendered Span API docs

docs/api.rst renders ddtrace.trace.Span with :members: but without :inherited-members:. Replacing the Python property with an inherited SpanData descriptor therefore removes context—including the detailed customer-facing documentation deleted here—from the generated Span API reference. Keep a documented forwarding property on Span or explicitly include and document this inherited member.

AGENTS.md reference: AGENTS.md:L24-L29

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datadog-datadog-prod-us1 · 2026-08-21T18:12:38Z

⚠️ Warnings

🚦 9 Pipeline jobs failed

DataDog/apm-reliability/dd-trace-py | build linux serverless: [amd64, cp315-cp315, v113741238-d2b8243-manylinux2014_x86_64, 1] — 🔧 Needs a code fix, caused by this PR

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DataDog/apm-reliability/dd-trace-py | build linux serverless: [amd64, cp315-cp315, v126532274-233089d-musllinux_1_2_x86_64, 1] — 🔧 Needs a code fix, caused by this PR

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DataDog/apm-reliability/dd-trace-py | build linux: [amd64, cp315-cp315, v113741238-d2b8243-manylinux2014_x86_64] — 🔧 Needs a code fix, caused by this PR

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ℹ️ Info

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🧪 All tests passed
❄️ No new flaky tests detected

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🔗 Commit SHA: bb2ee36 | Docs | View more details | Give us feedback!}

pr-commenter · 2026-08-21T18:25:53Z

Benchmarks

Benchmark execution time: 2026-08-21 20:31:27

Comparing candidate commit bb2ee36 in PR branch emmett.butler/native-context-3 with baseline commit 79d06af in branch emmett.butler/native-context-2.

📊 Benchmarking dashboard

Found 0 performance improvements and 11 performance regressions! Performance is the same for 601 metrics, 10 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

🟩 = significantly better candidate vs. baseline
🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

scenario:httppropagationextract-empty_headers

🟥 execution_time [+42.190ns; +49.887ns] or [+7.478%; +8.842%]

scenario:httppropagationextract-tracecontext_headers

🟥 execution_time [+2.290µs; +2.477µs] or [+7.207%; +7.797%]

scenario:httppropagationextract-wsgi_empty_headers

🟥 execution_time [+44.545ns; +52.958ns] or [+7.881%; +9.370%]

scenario:httppropagationinject-ids_only

🟥 execution_time [+1.972µs; +2.106µs] or [+11.972%; +12.786%]

scenario:iastaspects-casefold_noaspect

🟥 execution_time [+28.911µs; +34.758µs] or [+11.526%; +13.857%]

scenario:iastaspects-join_aspect

🟥 execution_time [+60.277µs; +64.782µs] or [+29.308%; +31.499%]

scenario:iastaspects-title_aspect

🟥 execution_time [+41.724µs; +47.615µs] or [+15.565%; +17.763%]

scenario:iastaspectsospath-ospathbasename_aspect

🟥 execution_time [+104.093µs; +111.523µs] or [+24.973%; +26.755%]

scenario:span-start

🟥 execution_time [+1.133ms; +1.293ms] or [+8.028%; +9.159%]

scenario:telemetryaddmetric-1-count-metric-1-times

🟥 execution_time [+297.730ns; +345.438ns] or [+11.118%; +12.899%]

scenario:tracer-small

🟥 execution_time [+26.460µs; +27.995µs] or [+8.007%; +8.471%]

Unstable benchmarks

These benchmarks have a confidence interval too wide to call a change; treat them as noise rather than signal.

scenario:coreapiscenario-context_with_data_listeners

unstable execution_time [-627.050ns; +860.070ns] or [-5.704%; +7.824%]

scenario:coreapiscenario-core_dispatch_1_listener

unstable execution_time [-30.737ns; +35.608ns] or [-4.984%; +5.774%]

scenario:coreapiscenario-core_dispatch_50_listeners

unstable execution_time [-1555.080ns; +1771.821ns] or [-9.067%; +10.331%]

scenario:coreapiscenario-core_dispatch_exception_listeners

unstable execution_time [-1069.270ns; +1396.103ns] or [-8.332%; +10.879%]

scenario:coreapiscenario-core_dispatch_listeners

unstable execution_time [-333.478ns; +324.980ns] or [-9.023%; +8.793%]

scenario:coreapiscenario-core_dispatch_no_args_listeners

unstable execution_time [-238.565ns; +280.380ns] or [-8.099%; +9.519%]

scenario:coreapiscenario-core_dispatch_with_results_1_listener

unstable execution_time [-74.559ns; +73.819ns] or [-6.214%; +6.152%]

scenario:coreapiscenario-core_dispatch_with_results_50_listeners

unstable execution_time [-3912.761ns; +4047.462ns] or [-9.591%; +9.921%]

scenario:coreapiscenario-core_dispatch_with_results_listeners

unstable execution_time [-768.717ns; +804.835ns] or [-9.416%; +9.859%]

scenario:packagesupdateimporteddependencies-import_many_stdlib_cached

unstable execution_time [-64.012µs; +57.707µs] or [-9.943%; +8.964%]

Co-authored-by: Brett Langdon <brett.langdon@datadoghq.com>

cit-pr-commenter-54b7da · 2026-08-21T18:31:53Z

Codeowners resolved as

Resolved from the full PR diff against emmett.butler/native-context-2 using the target branch CODEOWNERS file.
CODEOWNERS team requests not listed below are not required by the current file set.

ddtrace/_trace/sampling_rule.py                                         @DataDog/apm-sdk-capabilities-python
ddtrace/_trace/span.py                                                  @DataDog/apm-sdk-capabilities-python @DataDog/apm-core-python
ddtrace/internal/native/_native.pyi                                     @DataDog/apm-core-python
ddtrace/internal/sampling.py                                            @DataDog/apm-sdk-capabilities-python
src/native/context/context_data.rs                                      @DataDog/apm-core-python
src/native/span/span_data.rs                                            @DataDog/apm-core-python

cit-pr-commenter-54b7da · 2026-08-21T18:32:29Z

Circular import analysis

⚠️ Existing circular imports

There are 3 circular imports that already exist on the base branch and have not been changed by this PR.

ddtrace.errortracking._handled_exceptions.bytecode_injector -> ddtrace.errortracking._handled_exceptions.callbacks -> ddtrace.errortracking._handled_exceptions.collector -> ddtrace.errortracking._handled_exceptions.bytecode_reporting -> ddtrace.errortracking._handled_exceptions.bytecode_injector
ddtrace.llmobs -> ddtrace.llmobs._evaluators -> ddtrace.llmobs._evaluators.format -> ddtrace.llmobs._experiment -> ddtrace.llmobs
ddtrace.appsec._asm_request_context -> ddtrace.appsec._iast._iast_request_context_base -> ddtrace.appsec._iast._iast_env -> ddtrace.appsec._iast.reporter -> ddtrace.appsec._exploit_prevention.stack_traces -> ddtrace.appsec._asm_request_context

cit-pr-commenter-54b7da · 2026-08-21T18:32:33Z

Dependency direction analysis

⚠️ Existing dependency direction violations

There are 242 dependency direction violations that already exist on the base branch and have not been changed by this PR.

Show existing violations (showing 5 of 242 highest severity)

ddtrace.internal.tracemethods -×-> ddtrace.trace  (internal-core -> product:tracing, score=134)
ddtrace.llmobs._integrations.llama_index -×-> ddtrace.trace  (product:llmobs -> product:tracing, score=132)
ddtrace.internal.opentelemetry.trace -×-> ddtrace.trace  (product:opentelemetry -> product:tracing, score=132)
ddtrace.profiling.collector.stack -×-> ddtrace.trace  (product:profiling -> product:tracing, score=132)
ddtrace.debugging._debugger -×-> ddtrace.trace  (product:debugging -> product:tracing, score=132)

To see all violations, download the layers-base.json and layers-pr.json artifacts from this CI job and run:
uv run --script scripts/import-analysis/layers.py compare layers-base.json layers-pr.json

✅ Dependency direction violations removed

1 violation(s) have been removed by this PR.

ddtrace.internal.sampling -×-> ddtrace._trace.span  (internal-core -> product:tracing, score=58)

…ve-context-3

move sampling interfaces to SpanData and Context

c88b419

emmettbutler requested review from a team as code owners August 21, 2026 17:59

emmettbutler requested review from juanjux and rachelyangdog and removed request for a team August 21, 2026 17:59

emmettbutler marked this pull request as draft August 21, 2026 18:00

emmettbutler added the changelog/no-changelog A changelog entry is not required for this PR. label Aug 21, 2026

chatgpt-codex-connector Bot reviewed Aug 21, 2026

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brettlangdon reviewed Aug 21, 2026

View reviewed changes

Comment thread src/native/context/context_data.rs Outdated

Update src/native/context/context_data.rs

e9bbbc5

Co-authored-by: Brett Langdon <brett.langdon@datadoghq.com>

emmettbutler added 2 commits August 21, 2026 13:02

Merge branch 'emmett.butler/native-context-2' into emmett.butler/nati…

5b1561b

…ve-context-3

Remove Default derive from Context struct

bb2ee36

		# `context`/`_context` (lazy build of this span's trace Context, cached on
		# first read) are implemented natively on `SpanData` and inherited here.

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Benchmarks

Explanation

More details about the CI and significant changes

scenario:httppropagationextract-empty_headers

scenario:httppropagationextract-tracecontext_headers

scenario:httppropagationextract-wsgi_empty_headers

scenario:httppropagationinject-ids_only

scenario:iastaspects-casefold_noaspect

scenario:iastaspects-join_aspect

scenario:iastaspects-title_aspect

scenario:iastaspectsospath-ospathbasename_aspect

scenario:span-start

scenario:telemetryaddmetric-1-count-metric-1-times

scenario:tracer-small

Unstable benchmarks

scenario:coreapiscenario-context_with_data_listeners

scenario:coreapiscenario-core_dispatch_1_listener

scenario:coreapiscenario-core_dispatch_50_listeners

scenario:coreapiscenario-core_dispatch_exception_listeners

scenario:coreapiscenario-core_dispatch_listeners

scenario:coreapiscenario-core_dispatch_no_args_listeners

scenario:coreapiscenario-core_dispatch_with_results_1_listener

scenario:coreapiscenario-core_dispatch_with_results_50_listeners

scenario:coreapiscenario-core_dispatch_with_results_listeners

scenario:packagesupdateimporteddependencies-import_many_stdlib_cached

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Codeowners resolved as

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Circular import analysis

⚠️ Existing circular imports

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Dependency direction analysis

⚠️ Existing dependency direction violations

✅ Dependency direction violations removed

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