refactor(pubsub): remove EOL Python 3.7/3.8/3.9 false positives and compatibility checks (#17485)

Since `google-cloud-pubsub` requires Python >= 3.10, this PR cleans up
obsolete compatibility checks, warnings, and pytest skip conditions
targeting Python 3.7, 3.8, and 3.9.

Why this is needed:

* Simplifies the codebase by removing dead compatibility blocks and
checks that are always true under Python >= 3.10.
* Cleans up EOL warnings and deprecated import workarounds that are no
longer relevant to current runtimes.
* Cleans up unit test decorators to run all OpenTelemetry tests
unconditionally.
* Supports clean up efforts to eliminate false positives as found by the
version_scanner.
🦕

Author: chalmerlowe

packages/google-cloud-pubsub/CONTRIBUTING.rst

@@ -22,7 +22,7 @@ In order to add a feature:
   documentation.
 
 - The feature must work fully on the following CPython versions:
-  3.9, 3.10, 3.11, 3.12, 3.13 and 3.14 on both UNIX and Windows.
+  3.10, 3.11, 3.12, 3.13 and 3.14 on both UNIX and Windows.
 
 - The feature must not add unnecessary dependencies (where
   "unnecessary" is of course subjective, but new dependencies should
@@ -221,14 +221,12 @@ Supported Python Versions
 
 We support:
 
--  `Python 3.9`_
 -  `Python 3.10`_
 -  `Python 3.11`_
 -  `Python 3.12`_
 -  `Python 3.13`_
 -  `Python 3.14`_
 
-.. _Python 3.9: https://docs.python.org/3.9/
 .. _Python 3.10: https://docs.python.org/3.10/
 .. _Python 3.11: https://docs.python.org/3.11/
 .. _Python 3.12: https://docs.python.org/3.12/
@@ -241,18 +239,6 @@ Supported versions can be found in our ``noxfile.py`` `config`_.
 .. _config: https://github.com/googleapis/python-pubsub/blob/main/noxfile.py
 
 
-We also explicitly decided to support Python 3 beginning with version 3.7.
-Reasons for this include:
-
--  Encouraging use of newest versions of Python 3
--  Taking the lead of `prominent`_ open-source `projects`_
--  `Unicode literal support`_ which allows for a cleaner codebase that
-   works in both Python 2 and Python 3
-
-.. _prominent: https://docs.djangoproject.com/en/1.9/faq/install/#what-python-version-can-i-use-with-django
-.. _projects: http://flask.pocoo.org/docs/0.10/python3/
-.. _Unicode literal support: https://www.python.org/dev/peps/pep-0414/
-
 **********
 Versioning
 **********

packages/google-cloud-pubsub/README.rst

@@ -67,10 +67,6 @@ Python >= 3.10, including 3.14
 .. _active: https://devguide.python.org/devcycle/#in-development-main-branch
 .. _maintenance: https://devguide.python.org/devcycle/#maintenance-branches
 
-Unsupported Python Versions
-^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Python <= 3.9
-
 
 If you are using an `end-of-life`_
 version of Python, we recommend that you update as soon as possible to an actively supported version.

packages/google-cloud-pubsub/google/cloud/pubsub_v1/publisher/client.py

@@ -17,7 +17,6 @@
 import copy
 import logging
 import os
-import sys
 import threading
 import time
 import typing
@@ -165,18 +164,6 @@ def __init__(
         self._open_telemetry_enabled = (
             self.publisher_options.enable_open_telemetry_tracing
         )
-        # OpenTelemetry features used by the library are not supported in Python versions <= 3.7.
-        # Refer https://github.com/open-telemetry/opentelemetry-python/issues/3993#issuecomment-2211976389
-        if (
-            self.publisher_options.enable_open_telemetry_tracing
-            and sys.version_info.major == 3
-            and sys.version_info.minor < 8
-        ):
-            warnings.warn(
-                message="Open Telemetry for Python version 3.7 or lower is not supported. Disabling Open Telemetry tracing.",
-                category=RuntimeWarning,
-            )
-            self._open_telemetry_enabled = False
 
     @classmethod
     def from_service_account_file(  # type: ignore[override]

packages/google-cloud-pubsub/google/cloud/pubsub_v1/subscriber/_protocol/leaser.py

@@ -27,13 +27,7 @@
 )
 from google.cloud.pubsub_v1.subscriber._protocol.dispatcher import _MAX_BATCH_LATENCY
 
-try:
-    from collections.abc import KeysView
-
-    KeysView[None]  # KeysView is only subscriptable in Python 3.9+
-except TypeError:
-    # Deprecated since Python 3.9, thus only use as a fallback in older Python versions
-    from typing import KeysView
+from collections.abc import KeysView
 
 from google.cloud.pubsub_v1.subscriber._protocol import requests
 

packages/google-cloud-pubsub/google/cloud/pubsub_v1/subscriber/client.py

@@ -15,7 +15,6 @@
 from __future__ import absolute_import
 
 import os
-import sys
 import typing
 import warnings
 from typing import Any, Callable, Optional, Sequence, Union, cast
@@ -102,18 +101,6 @@ def __init__(
         self._open_telemetry_enabled = (
             self.subscriber_options.enable_open_telemetry_tracing
         )
-        # OpenTelemetry features used by the library are not supported in Python versions <= 3.7.
-        # Refer https://github.com/open-telemetry/opentelemetry-python/issues/3993#issuecomment-2211976389
-        if (
-            self.subscriber_options.enable_open_telemetry_tracing
-            and sys.version_info.major == 3
-            and sys.version_info.minor < 8
-        ):
-            warnings.warn(
-                message="Open Telemetry for Python version 3.7 or lower is not supported. Disabling Open Telemetry tracing.",
-                category=RuntimeWarning,
-            )
-            self._open_telemetry_enabled = False
 
     @property
     def open_telemetry_enabled(self) -> bool:

packages/google-cloud-pubsub/google/cloud/pubsub_v1/subscriber/scheduler.py

@@ -153,11 +153,6 @@ def shutdown(
         """
         dropped_messages = []
 
-        # Drop all pending item from the executor. Without this, the executor will also
-        # try to process any pending work items before termination, which is undesirable.
-        #
-        # TODO: Replace the logic below by passing `cancel_futures=True` to shutdown()
-        # once we only need to support Python 3.9+.
         try:
             while True:
                 work_item = self._executor._work_queue.get(block=False)

packages/google-cloud-pubsub/pytest.ini

@@ -16,8 +16,6 @@ filterwarnings =
     # Remove once the minimum supported version of googleapis-common-protos is 1.62.0
     ignore:.*pkg_resources.declare_namespace:DeprecationWarning
     ignore:.*pkg_resources is deprecated as an API:DeprecationWarning
-    # Remove once https://github.com/googleapis/gapic-generator-python/issues/2303 is fixed
-    ignore:The python-bigquery library will stop supporting Python 3.7:PendingDeprecationWarning
     # Remove once we move off credential files https://github.com/googleapis/google-auth-library-python/pull/1812
     # Note that these are used in tests only
     ignore:Your config file at [/home/kbuilder/.docker/config.json] contains these credential helper entries:DeprecationWarning

packages/google-cloud-pubsub/tests/system.py

@@ -447,11 +447,19 @@ def test_subscriber_not_leaking_open_sockets(
     subscriber = pubsub_v1.SubscriberClient(transport="grpc")
     subscriber_2 = pubsub_v1.SubscriberClient(transport="grpc")
 
+    # Construct a secondary publisher client to clean up the topic,
+    # so we can safely close the main publisher client inside the test.
+    if "Rest" in type(publisher._transport).__name__:
+        publisher_2 = pubsub_v1.PublisherClient(transport="rest")
+    else:
+        publisher_2 = pubsub_v1.PublisherClient(transport="grpc")
+
     cleanup.append(
         (subscriber_2.delete_subscription, (), {"subscription": subscription_path})
     )
     cleanup.append((subscriber_2.close, (), {}))
-    cleanup.append((publisher.delete_topic, (), {"topic": topic_path}))
+    cleanup.append((publisher_2.delete_topic, (), {"topic": topic_path}))
+    cleanup.append((publisher_2._transport.close, (), {}))
 
     # Create topic before starting to track connection count (any sockets opened
     # by the publisher client are not counted by this test).
@@ -477,7 +485,16 @@ def test_subscriber_not_leaking_open_sockets(
         response = subscriber.pull(subscription=subscription_path, max_messages=3)
         assert len(response.received_messages) == 3
 
-    conn_count_end = len(current_process.net_connections())
+    # Close the publisher client's transport used in the test to ensure all its socket connections
+    # (including any opened asynchronously on the background publisher threads) are closed.
+    publisher._transport.close()
+
+    # Wait a bit for the asynchronous channel teardown to complete and the socket to be closed.
+    for _ in range(30):
+        conn_count_end = len(current_process.net_connections())
+        if conn_count_end <= conn_count_start:
+            break
+        time.sleep(0.1)
 
     # To avoid flakiness, use <= in the assertion, since on rare occasions additional
     # sockets are closed, causing the == assertion to fail.

packages/google-cloud-pubsub/tests/unit/pubsub_v1/conftest.py

@@ -39,11 +39,27 @@ def set_trace_provider():
 
 @pytest.fixture(scope="function")
 def span_exporter():
+    """Provides an InMemorySpanExporter for testing OpenTelemetry traces.
+
+    Registers a SimpleSpanProcessor with the global TracerProvider at start,
+    and removes it during teardown to prevent trace/span processor accumulation
+    and test pollution across tests.
+    """
     exporter = InMemorySpanExporter()
     processor = SimpleSpanProcessor(exporter)
     provider = trace.get_tracer_provider()
     provider.add_span_processor(processor)
-    yield exporter
+    try:
+        yield exporter
+    finally:
+        if hasattr(provider, "_active_span_processor") and hasattr(
+            provider._active_span_processor, "_span_processors"
+        ):
+            processors = provider._active_span_processor._span_processors
+            if isinstance(processors, tuple):
+                provider._active_span_processor._span_processors = tuple(
+                    p for p in processors if p is not processor
+                )
 
 
 @pytest.fixture()

packages/google-cloud-pubsub/tests/unit/pubsub_v1/publisher/batch/test_thread.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 import datetime
-import sys
 import threading
 import time
 from unittest import mock
@@ -723,9 +722,6 @@ def test_batch_done_callback_called_on_publish_response_invalid():
 
 
 # Refer https://opentelemetry.io/docs/languages/python/#version-support
-@pytest.mark.skipif(
-    sys.version_info < (3, 8), reason="Open Telemetry requires python3.8 or higher"
-)
 def test_open_telemetry_commit_publish_rpc_span_none(span_exporter):
     """
     Test scenario where OpenTelemetry is enabled, publish RPC
@@ -771,9 +767,6 @@ def test_open_telemetry_commit_publish_rpc_span_none(span_exporter):
 
 
 # Refer https://opentelemetry.io/docs/languages/python/#version-support
-@pytest.mark.skipif(
-    sys.version_info < (3, 8), reason="Open Telemetry requires python3.8 or higher"
-)
 def test_open_telemetry_commit_publish_rpc_exception(span_exporter):
     TOPIC = "projects/projectID/topics/topicID"
     batch = create_batch(topic=TOPIC, enable_open_telemetry=True)
@@ -819,9 +812,6 @@ def test_open_telemetry_commit_publish_rpc_exception(span_exporter):
 
 
 # Refer https://opentelemetry.io/docs/languages/python/#version-support
-@pytest.mark.skipif(
-    sys.version_info < (3, 8), reason="Open Telemetry requires python3.8 or higher"
-)
 def test_opentelemetry_commit_sampling(span_exporter):
     TOPIC = "projects/projectID/topics/topic"
     batch = create_batch(
@@ -886,9 +876,6 @@ def test_opentelemetry_commit_sampling(span_exporter):
         assert span.events[1].name == "publish end"
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 8), reason="Open Telemetry requires python3.8 or higher"
-)
 def test_opentelemetry_commit(span_exporter):
     TOPIC = "projects/projectID/topics/topic"
     batch = create_batch(