Activate _dd.p.ksr tests for all languages [java@brian.marks/add-ksr-tag][dotnet@brian.marks/add-ksr-tag][ruby@brian.marks/add-ksr-tag][nodejs@brian.marks/add-ksr-tag][cpp@brian.marks/fix-ksr-formatting][rust@brian.marks/add-ksr-tag][golang@brian.marks/fix-ksr-default]

[bm1549]

Motivation

The test_sampling_knuth_sample_rate_trace_sampling_rule system test verifies that tracers set _dd.p.ksr in span meta when trace sampling rules are applied. This test was blocked by missing_feature overrides in all language manifests. Now that all tracers implement this feature, the test should be activated.

See RFC: "Transmit Knuth sampling rate to backend"

Changes

Manifest activation (commit 1)

Removes missing_feature overrides for test_sampling_knuth_sample_rate_trace_sampling_rule from 8 language manifests:

• manifests/cpp.yml
• manifests/golang.yml
• manifests/java.yml
• manifests/dotnet.yml
• manifests/nodejs.yml
• manifests/php.yml
• manifests/ruby.yml
• manifests/rust.yml

For Node.js and PHP, removed class-level missing_feature entries that were blocking all tests in the Test_Knuth_Sample_Rate class. Preserved individual extraction test version constraints for PHP.

New edge case tests (commit 2)

Added three new edge case tests for _dd.p.ksr:

• test_sampling_knuth_sample_rate_not_set_for_default — Verifies ksr is NOT set when no sampling rules or agent rates are configured (default sampling only)
• test_sampling_knuth_sample_rate_overwritten_by_local_sampling — Verifies that when a trace arrives with upstream ksr and the local tracer applies its own sampling rule, the local ksr overwrites the upstream value
• Additional parametrize case (0.5) for test_sampling_knuth_sample_rate_trace_sampling_rule — Verifies no trailing zeros in ksr formatting for rate 0.5

Added missing_feature entries in PHP manifest for the new ksr generation tests (PHP does not support ksr generation).

Workflow

1. ⚠️ Create your PR as draft ⚠️
2. Work on you PR until the CI passes
3. Mark it as ready for review

Related PRs across tracers:

• Java: Add _dd.p.ksr propagated tag for Knuth sampling rate dd-trace-java#10802
• .NET: Add _dd.p.ksr propagated tag for Knuth sampling rate dd-trace-dotnet#8287
• Ruby: Add _dd.p.ksr propagated tag for Knuth sampling rate dd-trace-rb#5436
• Node.js: Add _dd.p.ksr propagated tag for Knuth sampling rate dd-trace-js#7741
• PHP: Add _dd.p.ksr propagated tag for Knuth sampling rate dd-trace-php#3701
• Rust: feat: add _dd.p.ksr propagated tag for Knuth sampling rate dd-trace-rs#180
• C++: Fix _dd.p.ksr formatting to use 6 significant digits without trailing zeros dd-trace-cpp#288

Reviewer checklist

• Anything but tests/ or manifests/ is modified ? I have the approval from R&P team
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added, removed or renamed?
  • Get a review from R&P team

🤖 Generated with Claude Code

[github-actions]

CODEOWNERS have been resolved as:

manifests/cpp.yml                                                       @DataDog/dd-trace-cpp
manifests/dotnet.yml                                                    @DataDog/apm-dotnet @DataDog/asm-dotnet
manifests/golang.yml                                                    @DataDog/dd-trace-go-guild
manifests/java.yml                                                      @DataDog/asm-java @DataDog/apm-java
manifests/nodejs.yml                                                    @DataDog/dd-trace-js
manifests/php.yml                                                       @DataDog/apm-php @DataDog/asm-php
manifests/ruby.yml                                                      @DataDog/ruby-guild @DataDog/asm-ruby
manifests/rust.yml                                                      @DataDog/apm-rust
tests/parametric/test_sampling_span_tags.py                             @DataDog/system-tests-core @DataDog/apm-sdk-capabilities

[datadog-prod-us1-6]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

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