# 0.1.25 (June 19th, 2023)

This release of `tracing-attributes` fixes the Clippy lint
[`let_with_type_underscore`] in code generated by the `#[instrument]`
attribute in Rust 1.70+.

### Fixed

- Allow [`clippy::let_with_type_underscore`] in macro-generated code ([tokio-rs#2609])

Thanks to @coolreader19 for contributing to this release!

[tokio-rs#2609]: tokio-rs#2609

[`let_with_type_underscore`]: http://rust-lang.github.io/rust-clippy/rust-1.70.0/index.html#let_with_type_underscore

# 0.1.31 (May 11, 2023)

This release of `tracing-core` fixes a bug that caused threads which
call `dispatcher::get_default` _before_ a global default subscriber is
set to never see the global default once it is set. In addition, it
includes improvements for instrumentation performance in some cases,
especially when using a global default dispatcher.

### Fixed

- Fixed incorrect thread-local caching of `Dispatch::none` if
  `dispatcher::get_default` is called before
  `dispatcher::set_global_default` (tokio-rs#2593)

### Changed

- Cloning a `Dispatch` that points at a global default subscriber no
  longer requires an `Arc` reference count increment, improving
  performance substantially (tokio-rs#2593)
- `dispatcher::get_default` no longer attempts to access a thread local
  if the scoped dispatcher is not in use, improving performance when the
  default dispatcher is global (tokio-rs#2593)
- Added `#[inline]` annotations called by the `event!` and `span!`
  macros to reduce the size of macro-generated code and improve
  recording performance (tokio-rs#2555)

Thanks to new contributor @ldm0 for contributing to this release!

# tracing 0.1.38 (April 25th, 2023)

This `tracing` release changes the `Drop` implementation for
`Instrumented` `Future`s so that the attached `Span` is entered when
dropping the `Future`. This means that events emitted by the `Future`'s
`Drop` implementation will now be recorded within its `Span`. It also
adds `#[inline]` hints to methods called in the `event!` macro's
expansion, for an improvement in both binary size and performance.

Additionally, this release updates the `tracing-attributes` dependency
to [v0.1.24][attrs-0.1.24], which updates the [`syn`] dependency to
v2.x.x. `tracing-attributes` v0.1.24 also includes improvements to the
`#[instrument]` macro; see [the `tracing-attributes` 0.1.24 release
notes][attrs-0.1.24] for details.

### Added

- `Instrumented` futures will now enter the attached `Span` in their
  `Drop` implementation, allowing events emitted when dropping the
  future to occur within the span (tokio-rs#2562)
- `#[inline]` attributes for methods called by the `event!` macros,
  making generated code smaller (tokio-rs#2555)
- **attributes**: `level` argument to `#[instrument(err)]` and
  `#[instrument(ret)]` to override the level of the generated return
  value event (tokio-rs#2335)
- **attributes**: Improved compiler error message when `#[instrument]`
  is added to a `const fn` (tokio-rs#2418)

### Changed

- `tracing-attributes`: updated to [0.1.24][attrs-0.1.24]
- Removed unneeded `cfg-if` dependency (tokio-rs#2553)
- **attributes**: Updated [`syn`] dependency to 2.0 (tokio-rs#2516)

### Fixed

- **attributes**: Fix `clippy::unreachable` warnings in
  `#[instrument]`-generated code (tokio-rs#2356)
- **attributes**: Removed unused "visit" feature flag from `syn`
  dependency (tokio-rs#2530)

### Documented

- **attributes**: Documented default level for `#[instrument(err)]`
  (tokio-rs#2433)
- **attributes**: Improved documentation for levels in `#[instrument]`
  (tokio-rs#2350)

Thanks to @nitnelave, @jsgf, @Abhicodes-crypto, @LukeMathWalker,
@andrewpollack, @quad, @klensy, @davidpdrsn, @dbidwell94, @ldm0,
@NobodyXu, @ilsv, and @daxpedda for contributing to this release!

[`syn`]: https://crates.io/crates/syn
[attrs-0.1.24]:
    https://github.com/tokio-rs/tracing/releases/tag/tracing-attributes-0.1.24

# 0.1.24 (April 24th, 2023)

This release of `tracing-attributes` adds support for passing an
optional `level` to the `err` and `ret` arguments to `#[instrument]`,
allowing the level of the generated return-value event to be overridden.
For example,

```rust
#[instrument(err(level = "info"))]
fn my_great_function() -> Result<(), &'static str> {
    // ...
}
```

will emit an `INFO`-level event if the function returns an `Err`.

In addition, this release updates the [`syn`] dependency to v2.x.x.

### Added

- `level` argument to `err` and `ret` to override the level of the
  generated return value event (tokio-rs#2335)
- Improved compiler error message when `#[instrument]` is added to a
  `const fn` (tokio-rs#2418)

### Changed

- Updated `syn` dependency to 2.0 (tokio-rs#2516)

### Fixed

- Fix `clippy::unreachable` warnings in `#[instrument]`-generated code
  (tokio-rs#2356)
- Removed unused "visit" feature flag from `syn` dependency (tokio-rs#2530)

### Documented

- Documented default level for `err` (tokio-rs#2433)
- Improved documentation for levels in `#[instrument]` (tokio-rs#2350)

Thanks to @nitnelave, @jsgf, @Abhicodes-crypto, @LukeMathWalker,
@andrewpollack, @quad, @klensy, @davidpdrsn, and @dbidwell94 for
contributign to this release!

[`syn`]: https://crates.io/crates/syn

# 0.3.17 (April 21, 2023)

This release of `tracing-subscriber` fixes a build error when using
`env-filter` with recent versions of the `regex` crate. It also
introduces several minor API improvements.

### Fixed

- **env-filter**: Add "unicode-case" and "unicode-perl" to the `regex`
  dependency, fixing a build error with recent versions of `regex`
  (tokio-rs#2566)
- A number of minor documentation typos and other fixes (tokio-rs#2384, tokio-rs#2378,
  tokio-rs#2368, tokio-rs#2548)

### Added

- **filter**: Add `fmt::Display` impl for `filter::Targets` (tokio-rs#2343)
- **fmt**: Made `with_ansi(false)` no longer require the "ansi" feature,
  so that ANSI formatting escapes can be disabled without requiring
  ANSI-specific dependencies (tokio-rs#2532)

### Changed

- **fmt**: Dim targets in the `Compact` formatter, matching the default
  formatter (tokio-rs#2409)

Thanks to @keepsimple1, @andrewhalle, @LeoniePhiline, @LukeMathWalker,
@howardjohn, @daxpedda, and @dbidwell94 for contributing to this
release!

# 0.3.16 (October 6, 2022)

This release of `tracing-subscriber` fixes a regression introduced in
[v0.3.15][subscriber-0.3.15] where `Option::None`'s `Layer`
implementation would set the max level hint to `OFF`. In addition, it
adds several new APIs, including the `Filter::event_enabled` method for
filtering events based on fields values, and the ability to log internal
errors that occur when writing a log line.

This release also replaces the dependency on the unmaintained
[`ansi-term`] crate with the [`nu-ansi-term`] crate, resolving an
*informational* security advisory ([RUSTSEC-2021-0139] for
[`ansi-term`]'s maintainance status. This increases the minimum
supported Rust version (MSRV) to Rust 1.50+, although the crate should
still compile for the previous MSRV of Rust 1.49+ when the `ansi`
feature is not enabled.

### Fixed

- **layer**: `Option::None`'s `Layer` impl always setting the
  `max_level_hint` to `LevelFilter::OFF` (tokio-rs#2321)
- Compilation with `-Z minimal versions` (tokio-rs#2246)
- **env-filter**: Clarify that disabled level warnings are emitted by
  `tracing-subscriber` (tokio-rs#2285)

### Added

- **fmt**: Log internal errors to `stderr` if writing a log line fails
  (tokio-rs#2102)
- **fmt**: `FmtLayer::log_internal_errors` and
  `FmtSubscriber::log_internal_errors` methods for configuring whether
  internal writer errors are printed to `stderr` (tokio-rs#2102)
- **fmt**: `#[must_use]` attributes on builders to warn if a
  `Subscriber` is configured but not set as the default subscriber
  (tokio-rs#2239)
- **filter**: `Filter::event_enabled` method for filtering an event
  based on its fields (tokio-rs#2245, tokio-rs#2251)
- **filter**: `Targets::default_level` accessor (tokio-rs#2242)

### Changed

- **ansi**: Replaced dependency on unmaintained `ansi-term` crate with
  `nu-ansi-term` ((tokio-rs#2287, fixes informational advisory
  [RUSTSEC-2021-0139])
- `tracing-core`: updated to [0.1.30][core-0.1.30]
- Minimum Supported Rust Version (MSRV) increased to Rust 1.50+ (when
  the `ansi`) feature flag is enabled (tokio-rs#2287)

### Documented

- **fmt**: Correct inaccuracies in `fmt::init` documentation (tokio-rs#2224)
- **filter**: Fix incorrect doc link in `filter::Not` combinator
  (tokio-rs#2249)

Thanks to new contributors @cgbur, @DesmondWillowbrook, @RalfJung, and
@poliorcetics, as well as returning contributors @CAD97, @connec,
@jswrenn, @guswynn, and @bryangarza, for contributing to this release!

[nu-ansi-term]: https://github.com/nushell/nu-ansi-term
[ansi_term]: https://github.com/ogham/rust-ansi-term
[RUSTSEC-2021-0139]: https://rustsec.org/advisories/RUSTSEC-2021-0139.html
[core-0.1.30]: https://github.com/tokio-rs/tracing/releases/tag/tracing-core-0.1.30
[subscriber-0.3.15]: https://github.com/tokio-rs/tracing/releases/tag/tracing-subscriber-0.3.15

# 0.1.30 (October 6, 2022)

This release of `tracing-core` adds a new `on_register_dispatch` method
to the `Subscriber` trait to allow the `Subscriber` to perform
initialization after being registered as a `Dispatch`, and a
`WeakDispatch` type to allow a `Subscriber` to store its own `Dispatch`
without creating reference count cycles.

### Added

- `Subscriber::on_register_dispatch` method (tokio-rs#2269)
- `WeakDispatch` type and `Dispatch::downgrade()` function (tokio-rs#2293)

Thanks to @jswrenn for contributing to this release!

# 0.1.23 (October 6, 2022)

This release of `tracing-attributes` fixes a bug where compiler
diagnostic spans for type errors in `#[instrument]`ed `async fn`s have
the location of the `#[instrument]` attribute rather than the location
of the actual error, and a bug where inner attributes in
`#[instrument]`ed functions would cause a compiler error.

### Fixed

- Fix incorrect handling of inner attributes in `#[instrument]`ed
  functions (tokio-rs#2307)
- Add fake return to improve spans generated for type errors in `async
  fn`s (tokio-rs#2270)
- Updated `syn` dependency to fix compilation with `-Z minimal-versions`
  (tokio-rs#2246)

Thanks to new contributors @compiler-errors and @e-nomem, as well as
@CAD97, for contributing to this release!

# 0.1.37 (October 6, 2022)

This release of `tracing` incorporates changes from `tracing-core`
[v0.1.30][core-0.1.30] and `tracing-attributes` [v0.1.23][attrs-0.1.23],
including the new `Subscriber::on_register_dispatch` method for
performing late initialization after a `Subscriber` is registered as a
`Dispatch`, and bugfixes for the `#[instrument]` attribute.
Additionally, it fixes instances of the `bare_trait_objects` lint, which
is now a warning on `tracing`'s MSRV and will become an error in the
next edition.

### Fixed

- **attributes**: Incorrect handling of inner attributes in
  `#[instrument]`ed functions (tokio-rs#2307)
- **attributes**: Incorrect location of compiler diagnostic spans
  generated for type errors in `#[instrument]`ed `async fn`s (tokio-rs#2270)
- **attributes**: Updated `syn` dependency to fix compilation with `-Z
  minimal-versions` (tokio-rs#2246)
- `bare_trait_objects` warning in `valueset!` macro expansion (tokio-rs#2308)

### Added

- **core**: `Subscriber::on_register_dispatch` method (tokio-rs#2269)
- **core**: `WeakDispatch` type and `Dispatch::downgrade()` function
  (tokio-rs#2293)

### Changed

- `tracing-core`: updated to [0.1.30][core-0.1.30]
- `tracing-attributes`: updated to [0.1.23][attrs-0.1.23]

### Documented

- Added [`tracing-web`] and [`reqwest-tracing`] to related crates
  (tokio-rs#2283, tokio-rs#2331)

Thanks to new contributors @compiler-errors, @e-nomem, @WorldSEnder,
@Xiami2012, and @tl-rodrigo-gryzinski, as well as @jswrenn and @CAD97,
for contributing to this release!

[core-0.1.30]:
    https://github.com/tokio-rs/tracing/releases/tag/tracing-core-0.1.30
[attrs-0.1.23]:
    https://github.com/tokio-rs/tracing/releases/tag/tracing-attributes-0.1.23
[`tracing-web`]: https://crates.io/crates/tracing-web/
[`reqwest-tracing`]: https://crates.io/crates/reqwest-tracing/