v0.1.x: clean up warnings (tokio-rs#3069)

* chore: avoid warnings from unknown cfg flags

* core: address warning for static-mut-refs

* chore: clean up warnings

Cargo.toml

@@ -17,3 +17,8 @@ members = [
     "tracing-journald",
     "examples"
 ]
+
+ # This will be ignored with Rust older than 1.74, but for now that's okay;
+ # we're only using it to fix check-cfg issues that first appeared in Rust 1.80.
+[workspace.lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ["cfg(flaky_tests)", "cfg(tracing_unstable)"] }

examples/Cargo.toml

@@ -50,9 +50,12 @@ tempfile = "3"
 snafu = "0.6.10"
 thiserror = "1.0.31"
 
-# valuable examples 
+# valuable examples
 valuable = { version = "0.1.0", features = ["derive"] }
 
 [target.'cfg(tracing_unstable)'.dependencies]
 tracing-core = { path = "../tracing-core", version = "0.1.28", features = ["valuable"]}
 tracing-subscriber = { path = "../tracing-subscriber", version = "0.3.0", features = ["json", "env-filter", "valuable"]}
+
+[lints]
+workspace = true

examples/examples/sloggish/sloggish_subscriber.rs

@@ -38,7 +38,7 @@ pub struct CurrentSpanPerThread {
 impl CurrentSpanPerThread {
     pub fn new() -> Self {
         thread_local! {
-            static CURRENT: RefCell<Vec<Id>> = RefCell::new(vec![]);
+            static CURRENT: RefCell<Vec<Id>> = const { RefCell::new(vec![]) };
         };
         Self { current: &CURRENT }
     }

tracing-appender/src/lib.rs

@@ -24,7 +24,7 @@
 //!  - Using a [`RollingFileAppender`][rolling_struct] to perform writes to a log file. This will block on writes.
 //!  - Using *any* type implementing [`std::io::Write`][write] in a non-blocking fashion.
 //!  - Using a combination of [`NonBlocking`][non_blocking] and [`RollingFileAppender`][rolling_struct] to allow writes to a log file
-//! without blocking.
+//!    without blocking.
 //!
 //! ## File Appender
 //!

tracing-appender/src/rolling.rs

@@ -10,11 +10,11 @@
 //! The following helpers are available for creating a rolling file appender.
 //!
 //! - [`Rotation::minutely()`][minutely]: A new log file in the format of `some_directory/log_file_name_prefix.yyyy-MM-dd-HH-mm`
-//! will be created minutely (once per minute)
+//!   will be created minutely (once per minute)
 //! - [`Rotation::hourly()`][hourly]: A new log file in the format of `some_directory/log_file_name_prefix.yyyy-MM-dd-HH`
-//! will be created hourly
+//!   will be created hourly
 //! - [`Rotation::daily()`][daily]: A new log file in the format of `some_directory/log_file_name_prefix.yyyy-MM-dd`
-//! will be created daily
+//!   will be created daily
 //! - [`Rotation::never()`][never()]: This will result in log file located at `some_directory/log_file_name`
 //!
 //!

tracing-attributes/Cargo.toml

@@ -54,3 +54,6 @@ rustversion = "1.0.9"
 
 [badges]
 maintenance = { status = "experimental" }
+
+[lints]
+workspace = true

tracing-attributes/tests/instrument.rs

@@ -100,7 +100,7 @@ fn fields() {
 
 #[test]
 fn skip() {
-    struct UnDebug(pub u32);
+    struct UnDebug();
 
     #[instrument(target = "my_target", level = "debug", skip(_arg2, _arg3))]
     fn my_fn(arg1: usize, _arg2: UnDebug, _arg3: UnDebug) {}
@@ -147,9 +147,9 @@ fn skip() {
         .run_with_handle();
 
     with_default(subscriber, || {
-        my_fn(2, UnDebug(0), UnDebug(1));
-        my_fn(3, UnDebug(0), UnDebug(1));
-        my_fn2(2, UnDebug(0), UnDebug(1));
+        my_fn(2, UnDebug(), UnDebug());
+        my_fn(3, UnDebug(), UnDebug());
+        my_fn2(2, UnDebug(), UnDebug());
     });
 
     handle.assert_finished();

tracing-core/Cargo.toml

@@ -46,3 +46,6 @@ rustdoc-args = ["--cfg", "docsrs", "--cfg", "tracing_unstable"]
 # it's necessary to _also_ pass `--cfg tracing_unstable` to rustc, or else
 # dependencies will not be enabled, and the docs build will fail.
 rustc-args = ["--cfg", "tracing_unstable"]
+
+[lints]
+workspace = true

tracing-core/src/dispatcher.rs

@@ -123,6 +123,8 @@
 //! currently default `Dispatch`. This is used primarily by `tracing`
 //! instrumentation.
 //!
+use core::ptr::addr_of;
+
 use crate::{
     callsite, span,
     subscriber::{self, NoSubscriber, Subscriber},
@@ -144,12 +146,6 @@ use crate::stdlib::{
     error,
 };
 
-#[cfg(feature = "alloc")]
-use alloc::sync::{Arc, Weak};
-
-#[cfg(feature = "alloc")]
-use core::ops::Deref;
-
 /// `Dispatch` trace data to a [`Subscriber`].
 #[derive(Clone)]
 pub struct Dispatch {
@@ -187,10 +183,10 @@ enum Kind<T> {
 
 #[cfg(feature = "std")]
 thread_local! {
-    static CURRENT_STATE: State = State {
+    static CURRENT_STATE: State = const { State {
         default: RefCell::new(None),
         can_enter: Cell::new(true),
-    };
+    } };
 }
 
 static EXISTS: AtomicBool = AtomicBool::new(false);
@@ -455,7 +451,7 @@ fn get_global() -> &'static Dispatch {
     unsafe {
         // This is safe given the invariant that setting the global dispatcher
         // also sets `GLOBAL_INIT` to `INITIALIZED`.
-        &GLOBAL_DISPATCH
+        &*addr_of!(GLOBAL_DISPATCH)
     }
 }
 

tracing-core/src/field.rs

@@ -836,10 +836,7 @@ impl FieldSet {
     /// Returns the [`Field`] named `name`, or `None` if no such field exists.
     ///
     /// [`Field`]: super::Field
-    pub fn field<Q: ?Sized>(&self, name: &Q) -> Option<Field>
-    where
-        Q: Borrow<str>,
-    {
+    pub fn field<Q: Borrow<str> + ?Sized>(&self, name: &Q) -> Option<Field> {
         let name = &name.borrow();
         self.names.iter().position(|f| f == name).map(|i| Field {
             i,
@@ -1090,8 +1087,8 @@ mod test {
     use crate::stdlib::{borrow::ToOwned, string::String};
 
     // Make sure TEST_CALLSITE_* have non-zero size, so they can't be located at the same address.
-    struct TestCallsite1(u8);
-    static TEST_CALLSITE_1: TestCallsite1 = TestCallsite1(0);
+    struct TestCallsite1();
+    static TEST_CALLSITE_1: TestCallsite1 = TestCallsite1();
     static TEST_META_1: Metadata<'static> = metadata! {
         name: "field_test1",
         target: module_path!(),
@@ -1111,8 +1108,8 @@ mod test {
         }
     }
 
-    struct TestCallsite2(u8);
-    static TEST_CALLSITE_2: TestCallsite2 = TestCallsite2(0);
+    struct TestCallsite2();
+    static TEST_CALLSITE_2: TestCallsite2 = TestCallsite2();
     static TEST_META_2: Metadata<'static> = metadata! {
         name: "field_test2",
         target: module_path!(),

tracing-error/src/lib.rs

@@ -26,10 +26,10 @@
 //!
 //! - `traced-error` - Enables the [`TracedError`] type and related Traits
 //!     - [`InstrumentResult`] and [`InstrumentError`] extension traits, which
-//!     provide an [`in_current_span()`] method for bundling errors with a
-//!     [`SpanTrace`].
+//!       provide an [`in_current_span()`] method for bundling errors with a
+//!       [`SpanTrace`].
 //!     - [`ExtractSpanTrace`] extension trait, for extracting `SpanTrace`s from
-//!     behind `dyn Error` trait objects.
+//!       behind `dyn Error` trait objects.
 //!
 //! ## Usage
 //!

tracing-futures/Cargo.toml

@@ -51,3 +51,6 @@ maintenance = { status = "actively-developed" }
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
+
+[lints]
+workspace = true

tracing-futures/src/executor/futures_01.rs

@@ -35,7 +35,7 @@ where
 }
 
 #[cfg(feature = "tokio")]
-#[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
+#[allow(unreachable_pub, unused_imports)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::tokio::*;
 
 #[cfg(feature = "tokio")]

tracing-futures/src/executor/mod.rs

@@ -1,12 +1,8 @@
 #[cfg(feature = "futures-01")]
 mod futures_01;
 
-#[cfg(feature = "futures_preview")]
-mod futures_preview;
-#[cfg(feature = "futures_preview")]
-pub use self::futures_preview::*;
-
 #[cfg(feature = "futures-03")]
 mod futures_03;
+#[allow(unreachable_pub, unused_imports)]
 #[cfg(feature = "futures-03")]
-pub use self::futures_03::*;
+pub use futures_03::*;

tracing-futures/tests/std_future.rs

@@ -54,6 +54,7 @@ fn span_on_drop() {
         }
     }
 
+    #[allow(dead_code)] // Field unused, but logs on `Drop`
     struct Fut(Option<AssertSpanOnDrop>);
 
     impl Future for Fut {

tracing-journald/Cargo.toml

@@ -24,3 +24,6 @@ tracing-subscriber = { path = "../tracing-subscriber", version = "0.3.0", defaul
 serde_json = "1.0.82"
 serde = { version = "1.0.140", features = ["derive"] }
 tracing = { path = "../tracing", version = "0.1.35" }
+
+[lints]
+workspace = true

tracing-log/Cargo.toml

@@ -45,3 +45,6 @@ rustdoc-args = ["--cfg", "docsrs"]
 [[bench]]
 name = "logging"
 harness = false
+
+[lints]
+workspace = true

tracing-log/src/interest_cache.rs

@@ -235,7 +235,7 @@ mod tests {
 
     fn lock_for_test() -> impl Drop {
         // We need to make sure only one test runs at a time.
-        static LOCK: Lazy<Mutex<()>> = Lazy::new(Mutex::new);
+        static LOCK: Lazy<Mutex<()>> = Lazy::new(|| Mutex::new(()));
 
         match LOCK.lock() {
             Ok(guard) => guard,

tracing-macros/Cargo.toml

@@ -25,3 +25,6 @@ tracing-subscriber = { path = "../tracing-subscriber", version = "0.3.0", featur
 
 [badges]
 maintenance = { status = "experimental" }
+
+[lints]
+workspace = true

tracing-mock/Cargo.toml

@@ -29,3 +29,6 @@ tokio-stream = { version = "0.1.9", optional = true }
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
+
+[lints]
+workspace = true

tracing-serde/Cargo.toml

@@ -34,3 +34,6 @@ valuable-serde = { version = "0.1.0", optional = true, default-features = false
 
 [badges]
 maintenance = { status = "experimental" }
+
+[lints]
+workspace = true