Revert "Fix explicit bucket histogram aggregation"

This reverts commit f1c6683.

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

@@ -398,12 +398,8 @@ def __init__(
         record_min_max: bool = True,
     ):
         super().__init__(attributes)
-
-        self._start_time_unix_nano = start_time_unix_nano
         self._boundaries = tuple(boundaries)
-        self._record_min_max = record_min_max
-
-        self._current_value = None
+        self._bucket_counts = self._get_empty_bucket_counts()
         self._min = inf
         self._max = -inf
         self._sum = 0
@@ -420,19 +416,15 @@ def _get_empty_bucket_counts(self) -> List[int]:
 
     def aggregate(self, measurement: Measurement) -> None:
 
-        with self._lock:
+        value = measurement.value
 
-            if self._current_value is None:
-                self._current_value = self._get_empty_bucket_counts()
+        if self._record_min_max:
+            self._min = min(self._min, value)
+            self._max = max(self._max, value)
 
-            value = measurement.value
+        self._sum += value
 
-            if self._record_min_max:
-                self._min = min(self._min, value)
-                self._max = max(self._max, value)
-
-            self._current_value[bisect_left(self._boundaries, value)] += 1
-            self._sum = self._sum + value
+        self._bucket_counts[bisect_left(self._boundaries, value)] += 1
 
     def collect(
         self,
@@ -443,8 +435,14 @@ def collect(
         Atomically return a point for the current value of the metric.
         """
         with self._lock:
+            if not any(self._bucket_counts):
+                return None
 
-            if aggregation_temporality is AggregationTemporality.DELTA:
+            bucket_counts = self._bucket_counts
+            start_time_unix_nano = self._start_time_unix_nano
+            sum_ = self._sum
+            max_ = self._max
+            min_ = self._min
 
             self._bucket_counts = self._get_empty_bucket_counts()
             self._start_time_unix_nano = collection_start_nano
@@ -489,39 +487,31 @@ def collect(
                     current_point.bucket_counts,
                     self._previous_point.bucket_counts,
                 )
-
-                self._current_value = None
-                self._min = inf
-                self._max = -inf
-                self._sum = 0
-                self._previous_collection_start_nano = collection_start_nano
-
-                if current_value is None:
-                    return None
-
-                return HistogramDataPoint(
-                    attributes=self._attributes,
-                    start_time_unix_nano=previous_collection_start_nano,
-                    time_unix_nano=collection_start_nano,
-                    count=sum(current_value),
-                    sum=sum_,
-                    bucket_counts=tuple(current_value),
-                    explicit_bounds=self._boundaries,
-                    min=min_,
-                    max=max_,
+            ]
+        else:
+            start_time_unix_nano = self._previous_point.time_unix_nano
+            sum_ = current_point.sum - self._previous_point.sum
+            bucket_counts = [
+                curr_count - prev_count
+                for curr_count, prev_count in zip(
+                    current_point.bucket_counts,
+                    self._previous_point.bucket_counts,
                 )
+            ]
 
-            return HistogramDataPoint(
-                attributes=self._attributes,
-                start_time_unix_nano=self._start_time_unix_nano,
-                time_unix_nano=collection_start_nano,
-                count=sum(self._current_value),
-                sum=self._sum,
-                bucket_counts=tuple(self._current_value),
-                explicit_bounds=self._boundaries,
-                min=self._min,
-                max=self._max,
-            )
+        current_point = HistogramDataPoint(
+            attributes=self._attributes,
+            start_time_unix_nano=start_time_unix_nano,
+            time_unix_nano=current_point.time_unix_nano,
+            count=sum(bucket_counts),
+            sum=sum_,
+            bucket_counts=tuple(bucket_counts),
+            explicit_bounds=current_point.explicit_bounds,
+            min=min_,
+            max=max_,
+        )
+        self._previous_point = current_point
+        return current_point
 
 
 # pylint: disable=protected-access

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

@@ -65,26 +65,17 @@ def test_histogram_counter_collection(self):
 
         metric_data = in_memory_metric_reader.get_metrics_data()
 
+        # FIXME ExplicitBucketHistogramAggregation is resetting counts to zero
+        # even if aggregation temporality is cumulative.
         self.assertEqual(
-            len(metric_data.resource_metrics[0].scope_metrics[0].metrics), 2
+            len(metric_data.resource_metrics[0].scope_metrics[0].metrics), 1
         )
-
         self.assertEqual(
             (
                 metric_data.resource_metrics[0]
                 .scope_metrics[0]
                 .metrics[0]
                 .data.data_points[0]
-                .bucket_counts
-            ),
-            (0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
-        )
-        self.assertEqual(
-            (
-                metric_data.resource_metrics[0]
-                .scope_metrics[0]
-                .metrics[1]
-                .data.data_points[0]
                 .value
             ),
             1,