CHANGELOG.md

@@ -2,6 +2,22 @@
 
 <!-- <START NEW CHANGELOG ENTRY> -->
 
+## 7.4.3
+
+([Full Changelog](https://github.com/jupyter/jupyter_client/compare/v7.4.2...aa549b27d3622b1c381275777785f84dd3d5253d))
+
+### Bugs fixed
+
+- Defer creation of ready future [#858](https://github.com/jupyter/jupyter_client/pull/858) ([@blink1073](https://github.com/blink1073))
+
+### Contributors to this release
+
+([GitHub contributors page for this release](https://github.com/jupyter/jupyter_client/graphs/contributors?from=2022-10-11&to=2022-10-19&type=c))
+
+[@meeseeksmachine](https://github.com/search?q=repo%3Ajupyter%2Fjupyter_client+involves%3Ameeseeksmachine+updated%3A2022-10-11..2022-10-19&type=Issues)
+
+<!-- <END NEW CHANGELOG ENTRY> -->
+
 ## 7.4.2
 
 ([Full Changelog](https://github.com/jupyter/jupyter_client/compare/v7.4.1...0a45cc41e4ce73911e4367eddc1f0001a8431fc0))
@@ -16,8 +32,6 @@
 
 [@blink1073](https://github.com/search?q=repo%3Ajupyter%2Fjupyter_client+involves%3Ablink1073+updated%3A2022-10-11..2022-10-11&type=Issues)
 
-<!-- <END NEW CHANGELOG ENTRY> -->
-
 ## 7.4.1
 
 ([Full Changelog](https://github.com/jupyter/jupyter_client/compare/v7.4.0...0d87835d82d485aa3e870a63e76768bf439c3fe4))

jupyter_client/_version.py

@@ -2,7 +2,7 @@
 from typing import List
 from typing import Union
 
-__version__ = "7.4.2"
+__version__ = "7.4.3"
 
 # Build up version_info tuple for backwards compatibility
 pattern = r'(?P<major>\d+).(?P<minor>\d+).(?P<patch>\d+)(?P<rest>.*)'

jupyter_client/manager.py

@@ -55,6 +55,16 @@ class _ShutdownStatus(Enum):
 F = t.TypeVar('F', bound=t.Callable[..., t.Any])
 
 
+def _get_future() -> t.Union[Future, CFuture]:
+    """Get an appropriate Future object"""
+    try:
+        asyncio.get_running_loop()
+        return Future()
+    except RuntimeError:
+        # No event loop running, use concurrent future
+        return CFuture()
+
+
 def in_pending_state(method: F) -> F:
     """Sets the kernel to a pending state by
     creating a fresh Future for the KernelManager's `ready`
@@ -65,12 +75,8 @@ def in_pending_state(method: F) -> F:
     @functools.wraps(method)
     async def wrapper(self, *args, **kwargs):
         # Create a future for the decorated method
-        if self._attempted_start:
-            try:
-                self._ready = Future()
-            except RuntimeError:
-                # No event loop running, use concurrent future
-                self._ready = CFuture()
+        if self._attempted_start or not self._ready:
+            self._ready = _get_future()
         try:
             # call wrapped method, await, and set the result or exception.
             out = await method(self, *args, **kwargs)
@@ -92,19 +98,13 @@ class KernelManager(ConnectionFileMixin):
     This version starts kernels with Popen.
     """
 
-    _ready: t.Union[Future, CFuture]
+    _ready: t.Optional[t.Union[Future, CFuture]]
 
     def __init__(self, *args, **kwargs):
         super().__init__(**kwargs)
         self._shutdown_status = _ShutdownStatus.Unset
         self._attempted_start = False
-        # Create a place holder future.
-        try:
-            asyncio.get_running_loop()
-            self._ready = Future()
-        except RuntimeError:
-            # No event loop running, use concurrent future
-            self._ready = CFuture()
+        self._ready = None
 
     _created_context: Bool = Bool(False)
 
@@ -189,6 +189,8 @@ def _default_cache_ports(self) -> bool:
     @property
     def ready(self) -> t.Union[CFuture, Future]:
         """A future that resolves when the kernel process has started for the first time"""
+        if not self._ready:
+            self._ready = _get_future()
         return self._ready
 
     @property

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "jupyter_client"
-version = "7.4.2"
+version = "7.4.3"
 description = "Jupyter protocol implementation and client libraries"
 keywords = [ "Interactive", "Interpreter", "Shell", "Web",]
 classifiers = [
@@ -51,7 +51,7 @@ Homepage = "https://jupyter.org"
 test = [
     "codecov",
     "coverage",
-    "ipykernel>=6.5",
+    "ipykernel>=6.12",
     "ipython",
     "mypy",
     "pre-commit",
@@ -93,7 +93,7 @@ skip = ["check-links"]
 ignore = [".mailmap", "*.yml", "*.yaml"]
 
 [tool.tbump.version]
-current = "7.4.2"
+current = "7.4.3"
 regex = '''
   (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)
   ((?P<channel>a|b|rc|.dev)(?P<release>\d+))?