React Navigation v6: Unresolved Decision on Nested Navigator Param Merging

Direct answers

1. Are nested navigator params merged into the parent? No. React Navigation v6 keeps each navigator’s route.params isolated; a deep link that targets a screen inside a nested stack only sets params on that screen.
2. If merging occurred, what would be the precedence? Merging does not happen by default, so there is no conflict. If you manually pass parent params as initialParams to the nested screen, the nested screen’s params (including those from the deep link) override any identically‑named keys you passed.
3. How do getInitialURL and subscribe affect this? These async linking functions only resolve the URL and deliver the parsed params to the target screen’s route.params. They do not trigger any automatic merge with the parent navigator. Concurrent navigation actions (e.g., a push followed by a pop) that occur after the linking resolution behave normally; to avoid race conditions, wait for the linking promise to resolve before dispatching further navigation actions.

Likely explanation

The design isolates navigators to prevent unintended prop leakage. Automatic merging would couple navigators and make debugging harder, so the library requires explicit opt‑in via initialParams or by passing props when rendering the nested navigator.

Steps to handle params correctly

1. Identify the nested navigator (e.g., a Stack.Navigator inside a Tab.Navigator).
2. In the parent screen component, read the needed params with const { params } = useRoute();.
3. Pass those params as initialParams (or as props) to the nested screen: <Stack.Screen name="Child" initialParams={parentParams} />.
4. Inside the nested screen, access the params again with useRoute().params.
5. If you need to combine parent defaults with child‑specific values, merge the objects manually before passing them as initialParams.

Missing diagnostic detail

If you observe that parent navigation state changes after a deep link, please share your linking configuration (especially any custom getInitialURL or subscribe logic) so we can verify whether an explicit merge is being performed.