fix(subscriber): panic when reloading Filtered #3328
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Motivation
Resolve #1629 without introducing a breaking change.
A workaround for this issue was introduced via
filter_mut, which allows reloading theFilterof aFilteredlayer — but it still doesn't support replacing the entireFilteredlayer.A breaking change was also proposed, but it comes with some downsides:
Alternativessection here, it could introduce unintended side effects.Solution
This change adds support for reloading filtered layers without breaking the existing API by introducing a dedicated
Handle::reload_filteredmethod for reloadingFilteredlayers, and aLayer::on_reload_layermethod for performing late initialization when aLayeris reloaded.Handle::reload_filteredinvokes the newLayer::on_reload_layermethod on the layer. This method is responsible for registering the filter with the subscriber viaregister_filter_immut.Unlike
register_filter, theregister_filter_immutfunction takes a shared reference to the subscriber, allowing filter registration after the subscriber has been fully initialized.Usage examples for are included in the inline documentation.
Fixes: #1629