use_effect's unmount method is not always called with dynamically rendered children #1198
Description
Current Situation
This issue was first discovered while trying to develop reactive-python/reactpy-django#226
I created a component that simulates a list of conditionally rendered children. Each child in the list contains a unique key. However, the use_effect unmount method does not always appear to be called when the component is dismounted.
Here is a minimum viable example:
from uuid import uuid4
from reactpy import component, hooks, html, run
@component
def child():
ownership_uuid = hooks.use_memo(lambda: uuid4().hex)
@hooks.use_effect(dependencies=[])
async def unmount_manager():
print("registering new unmount func")
def unmount():
# FIXME: This is not working as expected. Dismount is not always called.
print("unmount func called")
return unmount
return ownership_uuid
@component
def root():
components = hooks.use_ref([child(key=uuid4().hex)])
reload_trigger, set_reload_trigger = hooks.use_state(True)
async def add_front_child(event):
components.current.insert(0, child(key=uuid4().hex))
set_reload_trigger(not reload_trigger)
async def add_end_child(event):
components.current.append(child(key=uuid4().hex))
set_reload_trigger(not reload_trigger)
async def remove_front_child(event):
if components.current:
components.current.pop(0)
set_reload_trigger(not reload_trigger)
async def remove_end_child(event):
if components.current:
components.current.pop()
set_reload_trigger(not reload_trigger)
return html.div(
html.div(
html.button({"on_click": add_front_child}, "Add End"),
html.button({"on_click": add_end_child}, "Add Front"),
html.button({"on_click": remove_front_child}, "Remove End"),
html.button({"on_click": remove_end_child}, "Remove Front"),
),
html.div(f"Components: {components.current}"),
components.current,
)
run(root)You can demo this by adding a bunch of children, then removing them. If you look at terminal, you'll notice that unmount was only called once despite multiple children being unloaded.
Proposed Actions
No response