Bluetooth: Host: remove unused bt_le_set_auto_conn()

[ivaniushkov]

bt_le_set_auto_conn() doesn't work as expected.
When it is used notify_disconnected() is not called, also reconnection doesn't work.
I didn't find easy way to fix it and I think it was broken for a long time.
Instead of using this function, a user application can implement reconnecting to the disconnected device by starting scanner again and connecting manually

fixes #81230

[cvinayak]

You cannot directly remove a public API, it needs be deprecated first. https://docs.zephyrproject.org/latest/develop/api/api_lifecycle.html#api-lifecycle

[ivaniushkov]

You cannot directly remove a public API, it needs be deprecated first. https://docs.zephyrproject.org/latest/develop/api/api_lifecycle.html#api-lifecycle

Thank you, it is a good point.
I see at the page you linked that unstable API can be removed without deprecation:

Unstable APIs can be removed without deprecation at any time. Deprecation and removal of APIs will be announced in the “API Changes” section of the release notes.

I guess, this API can be treated as unstable since there are no tests or samples using it, and it is practically not working

[Thalley]

I guess, this API can be treated as unstable since there are no tests or samples using it, and it is practically not working

Stable/unstable here refers to the API and not the implementation. Unless specified as unstable or experimental, APIs are considered stable. It's described in more detail at https://docs.zephyrproject.org/latest/develop/api/api_lifecycle.html

[rugeGerritsen]

Sounds like we should anyways deprecate the API now. There is no point in keeping it if it doesn't work.

[Thalley]

Sounds like we should anyways deprecate the API now. There is no point in keeping it if it doesn't work.

The alternative is of course also to fix it :)

I have no idea how many uses it, but ideally we would hear from users if we follow the deprecation procedure.

If I understand correctly, this is the functionality used to use the filter accept list during connection. Looks like this is the only way for applications to use the FAL, so if we remove this function, we should offer the functionality in another way.

[ivaniushkov]

Sounds like we should anyways deprecate the API now. There is no point in keeping it if it doesn't work.

The alternative is of course also to fix it :)

I have no idea how many uses it, but ideally we would hear from users if we follow the deprecation procedure.

If I understand correctly, this is the functionality used to use the filter accept list during connection. Looks like this is the only way for applications to use the FAL, so if we remove this function, we should offer the functionality in another way.

but the implementation of this function is compiled only when CONFIG_BT_FILTER_ACCEPT_LIST is disabled so it should not affect FAL users

#if !defined(CONFIG_BT_FILTER_ACCEPT_LIST)
int bt_le_set_auto_conn(const bt_addr_le_t *addr,
			const struct bt_le_conn_param *param)
...
#endif  /* !defined(CONFIG_BT_FILTER_ACCEPT_LIST) */

[Thalley]

Sounds like we should anyways deprecate the API now. There is no point in keeping it if it doesn't work.

The alternative is of course also to fix it :)
I have no idea how many uses it, but ideally we would hear from users if we follow the deprecation procedure.
If I understand correctly, this is the functionality used to use the filter accept list during connection. Looks like this is the only way for applications to use the FAL, so if we remove this function, we should offer the functionality in another way.

but the implementation of this function is compiled only when CONFIG_BT_FILTER_ACCEPT_LIST is disabled so it should not affect FAL users

#if !defined(CONFIG_BT_FILTER_ACCEPT_LIST)
int bt_le_set_auto_conn(const bt_addr_le_t *addr,
			const struct bt_le_conn_param *param)
...
#endif  /* !defined(CONFIG_BT_FILTER_ACCEPT_LIST) */

Sorry yes, I had confused it with bt_conn_le_create_auto :)

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