Inject uvloop in Python 3.11+ explicitly (mandatory for Python 3.14+)

Signed-off-by: Sergey Vasilyev <[email protected]>

Author: nolar

kopf/_kits/loops.py

@@ -1,10 +1,12 @@
 import asyncio
 import contextlib
-from collections.abc import Generator
+import sys
+from collections.abc import Iterator
+from typing import Optional
 
 
 @contextlib.contextmanager
-def proper_loop(suggested_loop: asyncio.AbstractEventLoop | None = None) -> Generator[None, None, None]:
+def proper_loop(suggested_loop: Optional[asyncio.AbstractEventLoop] = None) -> Iterator[asyncio.AbstractEventLoop | None]:
     """
     Ensure that we have the proper loop, either suggested or properly managed.
 
@@ -15,22 +17,43 @@ def proper_loop(suggested_loop: asyncio.AbstractEventLoop | None = None) -> Gene
     This loop manager is usually used in CLI only, not deeper than that;
     i.e. not even in ``kopf.run()``, since uvloop is only auto-managed for CLI.
     """
-    original_policy = asyncio.get_event_loop_policy()
-    if suggested_loop is None:  # the pure CLI use, not a KopfRunner or other code
+    # Event loop policies were deprecated in 3.14 entirely. Yet they still exist in older versions.
+    # However, the asyncio.Runner was introduced in Python 3.11, so we can use the logic from there.
+    if suggested_loop is not None:
+        yield suggested_loop
+
+    elif sys.version_info >= (3, 11):  # optional in 3.11-3.13, mandatory in >=3.14
+        # Use uvloop if available by injecting it as the selected loop.
         try:
             import uvloop
         except ImportError:
             pass
         else:
-            asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())
+            with asyncio.Runner(loop_factory=uvloop.new_event_loop) as runner:
+                yield runner.get_loop()
+                return
+
+        # Use the default loop/runner in place, do not inject anything.
+        yield None
 
-    try:
-        yield
+    # For Python<=3.10, use the event-loop-policy-based injection.
+    else:
+        original_policy = asyncio.get_event_loop_policy()
+        if suggested_loop is None:  # the pure CLI use, not a KopfRunner or other code
+            try:
+                import uvloop
+            except ImportError:
+                pass
+            else:
+                asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())
 
-    finally:
         try:
-            import uvloop
-        except ImportError:
-            pass
-        else:
-            asyncio.set_event_loop_policy(original_policy)
+            yield
+
+        finally:
+            try:
+                import uvloop
+            except ImportError:
+                pass
+            else:
+                asyncio.set_event_loop_policy(original_policy)

kopf/cli.py

@@ -95,7 +95,7 @@ def run(
         paths=paths,
         modules=modules,
     )
-    with loops.proper_loop(__controls.loop):
+    with loops.proper_loop(suggested_loop=__controls.loop) as actual_loop:
         return running.run(
             standalone=standalone,
             namespaces=namespaces,
@@ -108,7 +108,7 @@ def run(
             stop_flag=__controls.stop_flag,
             ready_flag=__controls.ready_flag,
             vault=__controls.vault,
-            loop=__controls.loop,
+            loop=actual_loop,
         )
 
 
@@ -141,13 +141,14 @@ def freeze(
     settings = configuration.OperatorSettings()
     settings.peering.name = peering_name
     settings.peering.priority = priority
-    with loops.proper_loop(__controls.loop):
+    with loops.proper_loop(suggested_loop=__controls.loop) as actual_loop:
         return running.run(
             clusterwide=clusterwide,
             namespaces=namespaces,
             insights=insights,
             identity=identity,
             settings=settings,
+            loop=actual_loop,
             _command=peering.touch_command(
                 insights=insights,
                 identity=identity,
@@ -174,13 +175,14 @@ def resume(
     insights = references.Insights()
     settings = configuration.OperatorSettings()
     settings.peering.name = peering_name
-    with loops.proper_loop(__controls.loop):
+    with loops.proper_loop(suggested_loop=__controls.loop) as actual_loop:
         return running.run(
             clusterwide=clusterwide,
             namespaces=namespaces,
             insights=insights,
             identity=identity,
             settings=settings,
+            loop=actual_loop,
             _command=peering.touch_command(
                 insights=insights,
                 identity=identity,