Activate _dd.p.ksr tests for all languages

manifests/cpp.yml

@@ -231,8 +231,7 @@ manifest:
       component_version: '>=2.0.0'
   tests/parametric/test_sampling_delegation.py::Test_Decisionless_Extraction: ">1.0.0"
   tests/parametric/test_sampling_manual.py::Test_Manual_Sampling: bug (APMAPI-1720)  # Manual keep did not override the upstream drop decision
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=2.0.0'  # Modified by easy win activation script
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_knuth_sample_rate_trace_sampling_rule: missing_feature  # Created by easy win activation script
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=2.1.0'
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_appsec_enabled_sst011: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_dropped_sst001: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_kept_sst007: bug (APMAPI-737)

manifests/dotnet.yml

@@ -959,8 +959,7 @@ manifest:
   tests/parametric/test_partial_flushing.py::Test_Partial_Flushing::test_partial_flushing_one_span_default: missing_feature (partial flushing not enabled by default)
   tests/parametric/test_process_discovery.py::Test_ProcessDiscovery: '>=3.36.0'  # Modified by easy win activation script
   tests/parametric/test_process_discovery.py::Test_ProcessDiscovery::test_metadata_content_with_process_tags: missing_feature  # Created by easy win activation script
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=3.36.0'  # Modified by easy win activation script
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_knuth_sample_rate_trace_sampling_rule: missing_feature  # Created by easy win activation script
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=3.41.0'
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_appsec_enabled_sst011: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_dropped_sst001: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_kept_sst007: bug (APMAPI-737)

manifests/golang.yml

@@ -1151,8 +1151,7 @@ manifest:
   tests/parametric/test_parametric_endpoints.py::Test_Parametric_Write_Log::test_write_log: incomplete_test_app (Logs endpoint is only implemented in python and node.js app)
   tests/parametric/test_partial_flushing.py::Test_Partial_Flushing::test_partial_flushing_one_span_default: missing_feature (partial flushing not enabled by default)
   tests/parametric/test_process_discovery.py::Test_ProcessDiscovery: v2.2.3
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=2.5.0'  # Modified by easy win activation script
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_knuth_sample_rate_trace_sampling_rule: missing_feature  # Created by easy win activation script
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=2.8.0'
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_appsec_enabled_sst011: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_dropped_sst001: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_kept_sst007: bug (APMAPI-737)

manifests/java.yml

@@ -3702,8 +3702,7 @@ manifest:
   tests/parametric/test_partial_flushing.py::Test_Partial_Flushing::test_partial_flushing_one_span_default: 'missing_feature (java uses ''>'' so it needs one more span to force a partial flush)'
   tests/parametric/test_process_discovery.py::Test_ProcessDiscovery: v1.55.0-SNAPSHOT
   tests/parametric/test_sampling_manual.py::Test_Manual_Sampling: v1.59.0-SNAPSHOT+419da213f7
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=1.58.2+06122213c8'  # Modified by easy win activation script
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_knuth_sample_rate_trace_sampling_rule: missing_feature  # Created by easy win activation script
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=1.61.0'
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_appsec_enabled_sst011: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_dropped_sst001:
     - declaration: bug (APMAPI-737)

manifests/nodejs.yml

@@ -2059,7 +2059,7 @@ manifest:
   tests/parametric/test_partial_flushing.py::Test_Partial_Flushing: bug (APMLP-270)
   tests/parametric/test_process_discovery.py: missing_feature
   tests/parametric/test_sampling_manual.py::Test_Manual_Sampling: bug (APMAPI-1720)  # Manual keep did not override the upstream drop decision
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: missing_feature
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=5.93.0'
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_appsec_enabled_sst011: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_dropped_sst001: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_defaults_rate_1_and_rate_limit_0_sst008: bug (APMAPI-737)

manifests/php.yml

@@ -801,7 +801,7 @@ manifest:
   tests/parametric/test_partial_flushing.py::Test_Partial_Flushing::test_partial_flushing_under_limit_one_payload: '>=1.16.0'
   tests/parametric/test_process_discovery.py: missing_feature
   tests/parametric/test_sampling_delegation.py::Test_Decisionless_Extraction: v1.13.0+4663b2fa7c20c6920f347d059b57dc2a419cb7f7
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: missing_feature
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=1.18.0'
   ? tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_extract_knuth_sample_rate_distributed_tracing_datadog
   : '>=1.16.0'
   ? tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_extract_knuth_sample_rate_distributed_tracing_tracecontext

manifests/python.yml

@@ -1718,7 +1718,7 @@ manifest:
   tests/parametric/test_partial_flushing.py::Test_Partial_Flushing: flaky (APMAPI-734)
   tests/parametric/test_process_discovery.py::Test_ProcessDiscovery: v3.15.0+dev36.gb57f15308
   tests/parametric/test_sampling_delegation.py::Test_Decisionless_Extraction: v2.8.0
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: v3.14.0.dev
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: v4.7.0
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags: v2.8.0
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_appsec_enabled_sst011: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_dropped_sst001: bug (APMAPI-737)

manifests/ruby.yml

@@ -1496,8 +1496,7 @@ manifest:
   tests/parametric/test_process_discovery.py::Test_ProcessDiscovery: v2.18.0
   tests/parametric/test_process_discovery.py::Test_ProcessDiscovery::test_metadata_content_with_process_tags: missing_feature (Not yet implemented)
   tests/parametric/test_sampling_delegation.py::Test_Decisionless_Extraction: v2.4.0
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=2.27.0'  # Modified by easy win activation script
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_knuth_sample_rate_trace_sampling_rule: missing_feature  # Created by easy win activation script
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=2.31.0'
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_appsec_enabled_sst011: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_dropped_sst001: bug (APMAPI-737)
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags::test_tags_child_kept_sst007: bug (APMAPI-737)

manifests/rust.yml

@@ -237,7 +237,7 @@ manifest:
   tests/parametric/test_process_discovery.py: missing_feature
   tests/parametric/test_sampling_manual.py::Test_Manual_Sampling: missing_feature
   tests/parametric/test_sampling_span_tags.py: '>=0.2.1'  # Modified by easy win activation script
-  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate::test_sampling_knuth_sample_rate_trace_sampling_rule: missing_feature  # Created by easy win activation script
+  tests/parametric/test_sampling_span_tags.py::Test_Knuth_Sample_Rate: '>=0.4.0'
   tests/parametric/test_sampling_span_tags.py::Test_Sampling_Span_Tags: missing_feature  # Created by easy win activation script
   tests/parametric/test_span_events.py: missing_feature
   tests/parametric/test_span_links.py::Test_Span_Links: missing_feature

tests/parametric/test_sampling_span_tags.py

@@ -271,7 +271,7 @@ def test_tags_appsec_enabled_sst011(self, test_agent: TestAgentAPI, test_library
 @features.trace_sampling
 class Test_Knuth_Sample_Rate:
     @pytest.mark.parametrize(
-        ("library_env", "sample_rate"),
+        ("library_env", "expected_ksr"),
         [
             (
                 {
@@ -283,39 +283,51 @@ class Test_Knuth_Sample_Rate:
             (
                 {
                     "DD_TRACE_SAMPLE_RATE": None,
-                    "DD_TRACE_SAMPLING_RULES": '[{"sample_rate":0.7654321}]',
+                    "DD_TRACE_SAMPLING_RULES": '[{"sample_rate":0.000001}]',
                 },
-                "0.765432",
+                "0.000001",
+            ),
+            (
+                {
+                    "DD_TRACE_SAMPLE_RATE": None,
+                    "DD_TRACE_SAMPLING_RULES": '[{"sample_rate":0.0000001}]',
+                },
+                "0",
+            ),
+            (
+                {
+                    "DD_TRACE_SAMPLE_RATE": None,
+                    "DD_TRACE_SAMPLING_RULES": '[{"sample_rate":0.00000051}]',
+                },
+                "0.000001",
             ),
         ],
-        ids=["truncate_trailing_zeros", "percision_of_6_digits"],
+        ids=[
+            "rate_1_strips_trailing_zeros",
+            "six_decimal_precision_boundary",
+            "below_precision_rounds_to_zero",
+            "rounds_up_to_one_millionth",
+        ],
     )
     def test_sampling_knuth_sample_rate_trace_sampling_rule(
-        self, test_agent: TestAgentAPI, test_library: APMLibrary, sample_rate: str
+        self, test_agent: TestAgentAPI, test_library: APMLibrary, expected_ksr: str
     ):
         """When a trace is sampled via a sampling rule, the knuth sample rate
-        is sent to the agent on the chunk root span with the _dd.p.ksr key in the meta field.
+        is sent to the agent on the root span with the _dd.p.ksr key in the meta field.
+        The value is formatted with up to 6 decimal digits of precision, with trailing
+        zeros stripped.
         """
 
         with test_library:
-            with test_library.dd_start_span("span") as span1:
+            with test_library.dd_start_span("span"):
                 pass
             test_library.dd_flush()
 
-            with test_library.dd_start_span("span", parent_id=span1.span_id) as span2:
-                pass
-            test_library.dd_flush()
-
-            with test_library.dd_start_span("span", parent_id=span2.span_id):
-                pass
-            test_library.dd_flush()
-
-        traces = test_agent.wait_for_num_traces(3)
-        assert len(traces) == 3, f"Expected 3 traces: {traces}"
-        for trace in traces:
-            assert len(trace) == 1, f"Expected 1 span in the trace: {trace}"
-            span = trace[0]
-            assert span["meta"].get("_dd.p.ksr") == sample_rate, f"Expected {sample_rate} for span {span}"
+        traces = test_agent.wait_for_num_traces(1)
+        span = find_only_span(traces)
+        assert span["meta"].get("_dd.p.ksr") == expected_ksr, (
+            f"Expected _dd.p.ksr='{expected_ksr}', got: {span['meta'].get('_dd.p.ksr')}"
+        )
 
     @pytest.mark.parametrize(
         "library_env",
@@ -325,15 +337,22 @@ def test_sampling_knuth_sample_rate_trace_sampling_rule(
                 # Ensure sampling configurationations are not set.
                 "DD_TRACE_SAMPLE_RATE": None,
                 "DD_TRACE_SAMPLING_RULES": None,
-            }
+            },
+            {
+                "DD_TRACE_PROPAGATION_STYLE": "Datadog",
+                "DD_TRACE_SAMPLE_RATE": None,
+                # Verify upstream ksr is propagated unchanged even with local sampling rules set.
+                "DD_TRACE_SAMPLING_RULES": '[{"sample_rate":0.5}]',
+            },
         ],
     )
     def test_sampling_extract_knuth_sample_rate_distributed_tracing_datadog(
         self, test_agent: TestAgentAPI, test_library: APMLibrary
     ):
         """When a trace is extracted from datadog headers, the sampling decision
         and rate is extracted from X-Datadog-Sampling-Priority and X-Datadog-Tags
-        headers. These values are stored in the span's meta fields.
+        headers. These values are stored in the span's meta fields. The upstream
+        ksr is propagated unchanged even when local sampling rules are configured.
         """
         with test_library:
             incoming_headers = [
@@ -384,3 +403,27 @@ def test_sampling_extract_knuth_sample_rate_distributed_tracing_tracecontext(
         assert span["meta"].get("_dd.p.dm") == "-1"
         assert span["meta"].get("_dd.p.ksr") == "0.1"
         assert span["metrics"].get(SAMPLING_PRIORITY_KEY) == 2
+
+    @pytest.mark.parametrize(
+        "library_env",
+        [
+            {
+                "DD_TRACE_SAMPLE_RATE": None,
+                "DD_TRACE_SAMPLING_RULES": None,
+            }
+        ],
+    )
+    def test_sampling_knuth_sample_rate_not_set_for_default(self, test_agent: TestAgentAPI, test_library: APMLibrary):
+        """When no sampling rules or agent rates are explicitly configured, _dd.p.ksr
+        may or may not be present depending on how the tracer classifies the default
+        agent rate. If present, it must be "1" (the default rate of 1.0).
+        """
+        with test_library:
+            with test_library.dd_start_span("span"):
+                pass
+            test_library.dd_flush()
+
+        traces = test_agent.wait_for_num_traces(1)
+        span = find_only_span(traces)
+        ksr = span.get("meta", {}).get("_dd.p.ksr")
+        assert ksr is None or ksr == "1", f"If _dd.p.ksr is set for default sampling, it should be '1', got: {ksr}"