Bug fix for corrupted hook state - change hook state to a contextvar

---------

Co-authored-by: James Hutchison <[email protected]>

Author: Archmonger

src/reactpy/core/_life_cycle_hook.py

@@ -2,11 +2,11 @@
 
 import logging
 from asyncio import Event, Task, create_task, gather
+from contextvars import ContextVar, Token
 from typing import Any, Callable, Protocol, TypeVar
 
 from anyio import Semaphore
 
-from reactpy.core._thread_local import ThreadLocal
 from reactpy.core.types import ComponentType, Context, ContextProviderType
 
 T = TypeVar("T")
@@ -18,12 +18,27 @@ async def __call__(self, stop: Event) -> None: ...
 
 logger = logging.getLogger(__name__)
 
-_HOOK_STATE: ThreadLocal[list[LifeCycleHook]] = ThreadLocal(list)
+_hook_state = ContextVar("_hook_state")
+
+
+def create_hook_state(initial: list | None = None) -> Token[list]:
+    return _hook_state.set(initial or [])
+
+
+def clear_hook_state(token: Token[list]) -> None:
+    hook_stack = _hook_state.get()
+    if hook_stack:
+        logger.warning("clear_hook_state: Hook stack was not empty")
+    _hook_state.reset(token)
+
+
+def get_hook_state() -> list[LifeCycleHook]:
+    return _hook_state.get()
 
 
 def current_hook() -> LifeCycleHook:
     """Get the current :class:`LifeCycleHook`"""
-    hook_stack = _HOOK_STATE.get()
+    hook_stack = _hook_state.get()
     if not hook_stack:
         msg = "No life cycle hook is active. Are you rendering in a layout?"
         raise RuntimeError(msg)
@@ -130,7 +145,7 @@ def __init__(
         self._scheduled_render = False
         self._rendered_atleast_once = False
         self._current_state_index = 0
-        self._state: tuple[Any, ...] = ()
+        self._state: list = []
         self._effect_funcs: list[EffectFunc] = []
         self._effect_tasks: list[Task[None]] = []
         self._effect_stops: list[Event] = []
@@ -157,7 +172,7 @@ def use_state(self, function: Callable[[], T]) -> T:
         if not self._rendered_atleast_once:
             # since we're not initialized yet we're just appending state
             result = function()
-            self._state += (result,)
+            self._state.append(result)
         else:
             # once finalized we iterate over each succesively used piece of state
             result = self._state[self._current_state_index]
@@ -232,13 +247,13 @@ def set_current(self) -> None:
         This method is called by a layout before entering the render method
         of this hook's associated component.
         """
-        hook_stack = _HOOK_STATE.get()
+        hook_stack = get_hook_state()
         if hook_stack:
             parent = hook_stack[-1]
             self._context_providers.update(parent._context_providers)
         hook_stack.append(self)
 
     def unset_current(self) -> None:
         """Unset this hook as the active hook in this thread"""
-        if _HOOK_STATE.get().pop() is not self:
+        if get_hook_state().pop() is not self:
             raise RuntimeError("Hook stack is in an invalid state")  # nocov

src/reactpy/core/serve.py

@@ -9,6 +9,7 @@
 from anyio.abc import TaskGroup
 
 from reactpy.config import REACTPY_DEBUG_MODE
+from reactpy.core._life_cycle_hook import clear_hook_state, create_hook_state
 from reactpy.core.types import LayoutEventMessage, LayoutType, LayoutUpdateMessage
 
 logger = getLogger(__name__)
@@ -58,18 +59,22 @@ async def _single_outgoing_loop(
     layout: LayoutType[LayoutUpdateMessage, LayoutEventMessage], send: SendCoroutine
 ) -> None:
     while True:
-        update = await layout.render()
+        token = create_hook_state()
         try:
-            await send(update)
-        except Exception:  # nocov
-            if not REACTPY_DEBUG_MODE.current:
-                msg = (
-                    "Failed to send update. More info may be available "
-                    "if you enabling debug mode by setting "
-                    "`reactpy.config.REACTPY_DEBUG_MODE.current = True`."
-                )
-                logger.error(msg)
-            raise
+            update = await layout.render()
+            try:
+                await send(update)
+            except Exception:  # nocov
+                if not REACTPY_DEBUG_MODE.current:
+                    msg = (
+                        "Failed to send update. More info may be available "
+                        "if you enabling debug mode by setting "
+                        "`reactpy.config.REACTPY_DEBUG_MODE.current = True`."
+                    )
+                    logger.error(msg)
+                raise
+        finally:
+            clear_hook_state(token)
 
 
 async def _single_incoming_loop(