Avoid generator in _ViewInstrumentMatch.collect()

- Fix #3021
- Remove metric branch reference from CONTRIBUTING.md

Author: lancetarn

Diff for: .github/workflows/test.yml

@@ -10,7 +10,7 @@ env:
   # Otherwise, set variable to the commit of your branch on
   # opentelemetry-python-contrib which is compatible with these Core repo
   # changes.
-  CONTRIB_REPO_SHA: c6134843900e2eeb1b8b3383a897b38cc0905c38
+  CONTRIB_REPO_SHA: main
   # This is needed because we do not clone the core repo in contrib builds anymore.
   # When running contrib builds as part of core builds, we use actions/checkout@v2 which
   # does not set an environment variable (simply just runs tox), which is different when

Diff for: CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#3026](https://github.com/open-telemetry/opentelemetry-python/pull/3026))
 - Add missing entry points for OTLP/HTTP exporter
   ([#3027](https://github.com/open-telemetry/opentelemetry-python/pull/3027))
+- Fix: Avoid generator in metrics _ViewInstrumentMatch.collect()
+  ([#3035](https://github.com/open-telemetry/opentelemetry-python/pull/3035)
 
 ## Version 1.14.0/0.35b0 (2022-11-04)
 

Diff for: CONTRIBUTING.md

@@ -25,7 +25,7 @@ Please take a look at this list first, your contributions may belong in one of t
 
 # Find the right branch
 
-The default branch for this repo is `main`. Changes that pertain to `metrics` go into the `metrics` branch. Any changes that pertain to components marked as `stable` in the [specifications](https://github.com/open-telemetry/opentelemetry-specification) or anything that is not `metrics` related go into this branch.
+The default branch for this repo is `main`. All feature work is accomplished on branches from `main`.
 
 ## Find a Buddy and get Started Quickly!
 

Diff for: opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/_view_instrument_match.py

@@ -16,7 +16,7 @@
 from logging import getLogger
 from threading import Lock
 from time import time_ns
-from typing import Dict, Iterable
+from typing import Dict, List, Sequence
 
 from opentelemetry.metrics import Instrument
 from opentelemetry.sdk.metrics._internal.aggregation import (
@@ -126,12 +126,14 @@ def collect(
         self,
         aggregation_temporality: AggregationTemporality,
         collection_start_nanos: int,
-    ) -> Iterable[DataPointT]:
+    ) -> Sequence[DataPointT]:
 
+        data_points: List[DataPointT] = []
         with self._lock:
             for aggregation in self._attributes_aggregation.values():
                 data_point = aggregation.collect(
                     aggregation_temporality, collection_start_nanos
                 )
                 if data_point is not None:
-                    yield data_point
+                    data_points.append(data_point)
+        return data_points

Diff for: opentelemetry-sdk/tests/metrics/test_metrics.py

@@ -514,11 +514,11 @@ def test_duplicate_instrument_aggregate_data(self):
         self.assertEqual(metric_0.name, "counter")
         self.assertEqual(metric_0.unit, "unit")
         self.assertEqual(metric_0.description, "description")
-        self.assertEqual(next(metric_0.data.data_points).value, 3)
+        self.assertEqual(next(iter(metric_0.data.data_points)).value, 3)
 
         metric_1 = scope_metrics[1].metrics[0]
 
         self.assertEqual(metric_1.name, "counter")
         self.assertEqual(metric_1.unit, "unit")
         self.assertEqual(metric_1.description, "description")
-        self.assertEqual(next(metric_1.data.data_points).value, 7)
+        self.assertEqual(next(iter(metric_1.data.data_points)).value, 7)