06ecec499b
Currently, `Layered` only implements `fmt::Debug` if the outer layer, the inner layer, *and* the subscriber type parameters all implement `fmt::Debug`. However, in the case of a `Layered` with two `Layer`s, the subscriber itself is not present --- it's only a `PhantomData`. So the `fmt::Debug` implementation should be possible when only the actual `layer` and `inner` values are `Debug`. For the `PhantomData`, we can just print the type name. This means that `Layered` consisting of two `Layer`s and no `Subscriber` will now implement `Debug` if the `Layer`s are `Debug`, regardless of the subscriber type. When the `Layered` is a `Layer` and a `Subscriber`, the behavior will be the same, because the separate `PhantomData` subscriber type param is always the same as the type of the inner subscriber. Because printing the whole type name of the subscriber is potentially verbose (e.g. when the subscriber itself is a big pile of layers), we only include it in alt-mode.
tracing-subscriber
Utilities for implementing and composing tracing subscribers.
Compiler support: requires rustc 1.42+
Supported Rust Versions
Tracing is built against the latest stable release. The minimum supported version is 1.42. The current Tracing version is not guaranteed to build on Rust versions earlier than the minimum supported version.
Tracing follows the same compiler support policies as the rest of the Tokio project. The current stable Rust compiler and the three most recent minor versions before it will always be supported. For example, if the current stable compiler version is 1.45, the minimum supported version will not be increased past 1.42, three minor versions prior. Increasing the minimum supported compiler version is not considered a semver breaking change as long as doing so complies with this policy.
License
This project is licensed under the MIT license.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Tracing by you, shall be licensed as MIT, without any additional terms or conditions.