opentelemetry-sdk: fix explicit histogram aggregation to handle multiple explicit bucket advisories

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#4494](https://github.com/open-telemetry/opentelemetry-python/pull/4494))
 - Improve CI by cancelling stale runs and setting timeouts
   ([#4498](https://github.com/open-telemetry/opentelemetry-python/pull/4498))
+- Fix ExplicitBucketHistogramAggregation to handle multiple explicit bucket boundaries advisories ([#4521](https://github.com/open-telemetry/opentelemetry-python/pull/4521))
 
 ## Version 1.31.0/0.52b0 (2025-03-12)
 

opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/aggregation.py

@@ -1387,18 +1387,17 @@ def _create_aggregation(
                 AggregationTemporality.CUMULATIVE
             )
 
-        if self._boundaries is None:
-            self._boundaries = (
-                instrument._advisory.explicit_bucket_boundaries
-                or _DEFAULT_EXPLICIT_BUCKET_HISTOGRAM_AGGREGATION_BOUNDARIES
-            )
+        if self._boundaries:
+            boundaries = self._boundaries
+        else:
+            boundaries = instrument._advisory.explicit_bucket_boundaries
 
         return _ExplicitBucketHistogramAggregation(
             attributes,
             instrument_aggregation_temporality,
             start_time_unix_nano,
             reservoir_factory(_ExplicitBucketHistogramAggregation),
-            self._boundaries,
+            boundaries,
             self._record_min_max,
         )
 

opentelemetry-sdk/tests/metrics/integration_test/test_histogram_advisory_explicit_buckets.py

@@ -164,3 +164,47 @@ def test_explicit_aggregation(self):
         self.assertEqual(
             metric.data.data_points[0].explicit_bounds, (1.0, 2.0, 3.0)
         )
+
+    def test_explicit_aggregation_multiple_histograms(self):
+        reader = InMemoryMetricReader(
+            preferred_aggregation={
+                Histogram: ExplicitBucketHistogramAggregation()
+            }
+        )
+        meter_provider = MeterProvider(
+            metric_readers=[reader],
+        )
+        meter = meter_provider.get_meter("testmeter")
+
+        histogram1 = meter.create_histogram(
+            "testhistogram1",
+            explicit_bucket_boundaries_advisory=[1.0, 2.0, 3.0],
+        )
+        histogram1.record(1, {"label": "value"})
+        histogram1.record(2, {"label": "value"})
+        histogram1.record(3, {"label": "value"})
+
+        histogram2 = meter.create_histogram(
+            "testhistogram2",
+            explicit_bucket_boundaries_advisory=[4.0, 5.0, 6.0],
+        )
+        histogram2.record(4, {"label": "value"})
+        histogram2.record(5, {"label": "value"})
+        histogram2.record(6, {"label": "value"})
+
+        metrics = reader.get_metrics_data()
+        self.assertEqual(len(metrics.resource_metrics), 1)
+        self.assertEqual(len(metrics.resource_metrics[0].scope_metrics), 1)
+        self.assertEqual(
+            len(metrics.resource_metrics[0].scope_metrics[0].metrics), 2
+        )
+        metric1 = metrics.resource_metrics[0].scope_metrics[0].metrics[0]
+        self.assertEqual(metric1.name, "testhistogram1")
+        self.assertEqual(
+            metric1.data.data_points[0].explicit_bounds, (1.0, 2.0, 3.0)
+        )
+        metric2 = metrics.resource_metrics[0].scope_metrics[0].metrics[1]
+        self.assertEqual(metric2.name, "testhistogram2")
+        self.assertEqual(
+            metric2.data.data_points[0].explicit_bounds, (4.0, 5.0, 6.0)
+        )