diff --git a/tracing-subscriber/src/filter/layer_filters.rs b/tracing-subscriber/src/filter/layer_filters.rs index 5986dee14e..e0ad797585 100644 --- a/tracing-subscriber/src/filter/layer_filters.rs +++ b/tracing-subscriber/src/filter/layer_filters.rs @@ -380,7 +380,7 @@ where id if id == TypeId::of::() => { Some(&self.id as *const _ as *const ()) } - _ => None, + _ => self.layer.downcast_raw(id), } } } diff --git a/tracing-subscriber/tests/layer_filters/downcast_raw.rs b/tracing-subscriber/tests/layer_filters/downcast_raw.rs new file mode 100644 index 0000000000..b5f7e35ced --- /dev/null +++ b/tracing-subscriber/tests/layer_filters/downcast_raw.rs @@ -0,0 +1,68 @@ +use tracing::Subscriber; +use tracing_subscriber::filter::Targets; +use tracing_subscriber::prelude::*; +use tracing_subscriber::Layer; + +#[test] +fn downcast_ref_to_inner_layer_and_filter() { + // Test that a filtered layer gives downcast_ref access to + // both the layer and the filter. + + struct WrappedLayer; + + impl Layer for WrappedLayer + where + S: Subscriber, + S: for<'lookup> tracing_subscriber::registry::LookupSpan<'lookup>, + { + } + + let layer = WrappedLayer; + let filter = Targets::new().with_default(tracing::Level::INFO); + let registry = tracing_subscriber::registry().with(layer.with_filter(filter)); + let dispatch = tracing::dispatcher::Dispatch::new(registry); + + // The filter is available + assert!(dispatch.downcast_ref::().is_some()); + // The wrapped layer is available + assert!(dispatch.downcast_ref::().is_some()); +} + +#[test] +fn forward_downcast_raw_to_layer() { + // Test that a filtered layer still gives its wrapped layer a chance to + // return a custom struct from downcast_raw. + // https://github.com/tokio-rs/tracing/issues/1618 + + struct WrappedLayer { + with_context: WithContext, + } + + struct WithContext; + + impl Layer for WrappedLayer + where + S: Subscriber, + S: for<'lookup> tracing_subscriber::registry::LookupSpan<'lookup>, + { + unsafe fn downcast_raw(&self, id: std::any::TypeId) -> Option<*const ()> { + match id { + id if id == std::any::TypeId::of::() => Some(self as *const _ as *const ()), + id if id == std::any::TypeId::of::() => { + Some(&self.with_context as *const _ as *const ()) + } + _ => None, + } + } + } + + let layer = WrappedLayer { + with_context: WithContext, + }; + let filter = Targets::new().with_default(tracing::Level::INFO); + let registry = tracing_subscriber::registry().with(layer.with_filter(filter)); + let dispatch = tracing::dispatcher::Dispatch::new(registry); + + // Types from a custom implementation of `downcast_raw` are available + assert!(dispatch.downcast_ref::().is_some()); +} diff --git a/tracing-subscriber/tests/layer_filters/main.rs b/tracing-subscriber/tests/layer_filters/main.rs index ccc4ef2679..348c3fec91 100644 --- a/tracing-subscriber/tests/layer_filters/main.rs +++ b/tracing-subscriber/tests/layer_filters/main.rs @@ -2,6 +2,7 @@ #[path = "../support.rs"] mod support; use self::support::*; +mod downcast_raw; mod filter_scopes; mod targets; mod trees;