Exception while exporting metrics 'MetricsData' object has no attribute 'to_json'

[ebarti]

Describe your environment

Python 3.10. Docker compose.

opentelemetry-sdk = "1.12.0rc1"
opentelemetry-exporter-otlp = "1.12.0rc1"
opentelemetry-exporter-otlp-proto-grpc = "1.12.0rc1"

Steps to reproduce

Just following the getting started example...

from opentelemetry import metrics
from opentelemetry.metrics import (
     Counter,
)
from opentelemetry.sdk.metrics import MeterProvider
from opentelemetry.sdk.metrics.export import PeriodicExportingMetricReader, ConsoleMetricExporter

exporter = ConsoleMetricExporter()
reader = PeriodicExportingMetricReader(exporter)
provider = MeterProvider(metric_readers=[reader])
metrics.set_meter_provider(provider)
meter = metrics.get_meter(__name__)
counter = meter.create_counter("test")
counter.add(1)

What is the expected behavior?
Metrics printed to console

What is the actual behavior?

Traceback (most recent call last):
   File "/usr/local/lib/python3.10/site-packages/opentelemetry/sdk/metrics/_internal/export/__init__.py", line 404, in _receive_metrics
     self._exporter.export(metrics_data, timeout_millis=timeout_millis)
   File "/usr/local/lib/python3.10/site-packages/opentelemetry/sdk/metrics/_internal/export/__init__.py", line 121, in export
     self.out.write(self.formatter(metrics_data))
   File "/usr/local/lib/python3.10/site-packages/opentelemetry/sdk/metrics/_internal/export/__init__.py", line 109, in <lambda>
     ] = lambda metric: metric.to_json()
 AttributeError: 'MetricsData' object has no attribute 'to_json'
 Exception while exporting metrics 'MetricsData' object has no attribute 'to_json'

Additional context
Add any other context about the problem here.

[ebarti]

Fixed it by downgrading to 1.11 😅

[srikanthccv]

It's still a bug If it breaks on 1.12.0rc1.