tracing: fix macro hygiene for concat!
#1918
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hawkw
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Feb 9, 2022
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CI failure is due to a regression in the latest nightly (rust-lang/rust#93821), nothing we can do about it, so I'm going to go ahead and merge this. |
hawkw
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Feb 17, 2022
# 0.1.31 (February 17th, 2022) This release increases the minimum supported Rust version (MSRV) to 1.49.0. In addition, it fixes some relatively rare macro bugs. ### Added - Added `tracing-forest` to the list of related crates ([#1935]) ### Changed - Updated minimum supported Rust version (MSRV) to 1.49.0 ([#1913]) ### Fixed - Fixed the `warn!` macro incorrectly generating an event with the `TRACE` level ([#1930]) - Fixed macro hygiene issues when used in a crate that defines its own `concat!` macro, for real this time ([#1918]) Thanks to @QnnOkabayashi, @nicolaasg, and @teohhanhui for contributing to this release! [#1935]: #1935 [#1913]: #1913 [#1930]: #1930 [#1918]: #1918
hawkw
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Feb 17, 2022
# 0.1.31 (February 17th, 2022) This release increases the minimum supported Rust version (MSRV) to 1.49.0. In addition, it fixes some relatively rare macro bugs. ### Added - Added `tracing-forest` to the list of related crates ([#1935]) ### Changed - Updated minimum supported Rust version (MSRV) to 1.49.0 ([#1913]) ### Fixed - Fixed the `warn!` macro incorrectly generating an event with the `TRACE` level ([#1930]) - Fixed macro hygiene issues when used in a crate that defines its own `concat!` macro, for real this time ([#1918]) Thanks to @QnnOkabayashi, @nicolaasg, and @teohhanhui for contributing to this release! [#1935]: #1935 [#1913]: #1913 [#1930]: #1930 [#1918]: #1918
kaffarell
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May 22, 2024
Re-application of changes made in tokio-rs#1842 which were lost in f1cf1f1 Integration tests added for regression. --- ## Motivation In my library I define a `macro_rules! concat` macro, i.e. [`callbag::concat`](https://docs.rs/callbag/latest/callbag/macro.concat.html). When I try to call `tracing::info!(...)`, I get error output such as this: <details> <summary>error output</summary> <!-- leave a blank line above --> ``` > RUSTFLAGS='-Z macro-backtrace' cargo +nightly clippy --features trace Checking callbag v0.14.0 (/home/teohhanhui/projects/teohhanhui/callbag-rs) error[E0308]: mismatched types --> src/concat.rs:89:9 | 89 | info!("from sink: {message:?}"); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&str`, found `u32` error[E0277]: the trait bound `std::sync::Arc<core::Callbag<never::Never, _>>: std::convert::From<&str>` is not satisfied --> src/concat.rs:58:9 | 56 | / macro_rules! concat { 57 | | ($($s:expr),* $(,)?) => { 58 | | $crate::concat(::std::vec![$($s),*].into_boxed_slice()) | | ^^^^^^^^^^^^^^ the trait `std::convert::From<&str>` is not implemented for `std::sync::Arc<core::Callbag<never::Never, _>>` 59 | | }; 60 | | } | |_- in this expansion of `concat!` (tokio-rs#5) ... 89 | info!("from sink: {message:?}"); | ------------------------------- in this macro invocation (tokio-rs#1) | ::: src/utils/tracing.rs:47:1 | 47 | / macro_rules! info { 48 | | ($($arg:tt)+) => { 49 | | ::cfg_if::cfg_if! { 50 | | if #[cfg(feature = "trace")] { 51 | | ::tracing::info!($($arg)+) | | -------------------------- in this macro invocation (tokio-rs#2) ... | 54 | | }; 55 | | } | |_- in this expansion of `info!` (tokio-rs#1) | ::: /home/teohhanhui/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/tracing-0.1.29/src/macros.rs:586:1 | 586 | macro_rules! event { | _- | |_| | | 587 | | (target: $target:expr, parent: $parent:expr, $lvl:expr, { $($fields:tt)* } )=> ( 588 | | $crate::__tracing_log!( 589 | | target: $target, ... | 644 | name: concat!( | _______________________- 645 | "event ", 646 | file!(), 647 | ":", 648 | line!() 649 | | ), | |_________________- in this macro invocation (tokio-rs#5) ... 667 | / $crate::event!( 668 | target: $target, 669 | $lvl, 670 | { message = format_args!($($arg)+), $($fields)* } 671 | | ) | |_________- in this macro invocation (tokio-rs#4) ... 791 | | ); 792 | | } | | - | |_| | |_in this expansion of `$crate::event!` (tokio-rs#3) | in this expansion of `$crate::event!` (tokio-rs#4) ... 1229 | / macro_rules! info { 1230 | (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => ( 1231 | $crate::event!(target: $target, parent: $parent, $crate::Level::INFO, { $($field)* }, $($arg)*) 1232 | ); ... 1398 | / $crate::event!( 1399 | | target: module_path!(), 1400 | | $crate::Level::INFO, 1401 | | {}, 1402 | | $($arg)+ 1403 | | ) | |_________- in this macro invocation (tokio-rs#3) 1404 | ); 1405 | | } | |_- in this expansion of `::tracing::info!` (tokio-rs#2) | = help: the following implementations were found: <std::sync::Arc<B> as std::convert::From<std::borrow::Cow<'a, B>>> <std::sync::Arc<T> as std::convert::From<T>> <std::sync::Arc<T> as std::convert::From<std::boxed::Box<T>>> <std::sync::Arc<[T]> as std::convert::From<&[T]>> and 9 others = note: required because of the requirements on the impl of `std::convert::Into<std::sync::Arc<core::Callbag<never::Never, _>>>` for `&str` note: required by a bound in `concat::concat` --> src/concat.rs:81:8 | 72 | pub fn concat< | ------ required by a bound in this ... 81 | S: Into<Arc<Source<T>>> + Send + Sync, | ^^^^^^^^^^^^^^^^^^^^ required by this bound in `concat::concat` error[E0308]: mismatched types --> src/concat.rs:58:9 | 56 | / macro_rules! concat { 57 | | ($($s:expr),* $(,)?) => { 58 | | $crate::concat(::std::vec![$($s),*].into_boxed_slice()) | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&str`, found struct `core::Callbag` 59 | | }; 60 | | } | |_- in this expansion of `concat!` (tokio-rs#5) ... 89 | info!("from sink: {message:?}"); | ------------------------------- in this macro invocation (tokio-rs#1) | ::: src/utils/tracing.rs:47:1 | 47 | / macro_rules! info { 48 | | ($($arg:tt)+) => { 49 | | ::cfg_if::cfg_if! { 50 | | if #[cfg(feature = "trace")] { 51 | | ::tracing::info!($($arg)+) | | -------------------------- in this macro invocation (tokio-rs#2) ... | 54 | | }; 55 | | } | |_- in this expansion of `info!` (tokio-rs#1) | ::: /home/teohhanhui/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/tracing-0.1.29/src/macros.rs:586:1 | 586 | macro_rules! event { | _- | |_| | | 587 | | (target: $target:expr, parent: $parent:expr, $lvl:expr, { $($fields:tt)* } )=> ( 588 | | $crate::__tracing_log!( 589 | | target: $target, ... | 644 | name: concat!( | _______________________- 645 | "event ", 646 | file!(), 647 | ":", 648 | line!() 649 | | ), | |_________________- in this macro invocation (tokio-rs#5) ... 667 | / $crate::event!( 668 | target: $target, 669 | $lvl, 670 | { message = format_args!($($arg)+), $($fields)* } 671 | | ) | |_________- in this macro invocation (tokio-rs#4) ... 791 | | ); 792 | | } | | - | |_| | |_in this expansion of `$crate::event!` (tokio-rs#3) | in this expansion of `$crate::event!` (tokio-rs#4) ... 1229 | / macro_rules! info { 1230 | (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => ( 1231 | $crate::event!(target: $target, parent: $parent, $crate::Level::INFO, { $($field)* }, $($arg)*) 1232 | ); ... 1398 | / $crate::event!( 1399 | | target: module_path!(), 1400 | | $crate::Level::INFO, 1401 | | {}, 1402 | | $($arg)+ 1403 | | ) | |_________- in this macro invocation (tokio-rs#3) 1404 | ); 1405 | | } | |_- in this expansion of `::tracing::info!` (tokio-rs#2) | = note: expected reference `&'static str` found struct `core::Callbag<never::Never, _>` Some errors have detailed explanations: E0277, E0308. For more information about an error, try `rustc --explain E0277`. error: could not compile `callbag` due to 3 previous errors ``` </details> This is because of my `concat` macro being in scope. ## Solution Change all the `tracing` macros to use the re-export of `core::concat!` in the `__macro_support` module, rather than using an un-namespaced `concat!`. The re-export ensures that everything still works even in a crate that redefines the `core` name to something else.
kaffarell
pushed a commit
to kaffarell/tracing
that referenced
this pull request
May 22, 2024
# 0.1.31 (February 17th, 2022) This release increases the minimum supported Rust version (MSRV) to 1.49.0. In addition, it fixes some relatively rare macro bugs. ### Added - Added `tracing-forest` to the list of related crates ([tokio-rs#1935]) ### Changed - Updated minimum supported Rust version (MSRV) to 1.49.0 ([tokio-rs#1913]) ### Fixed - Fixed the `warn!` macro incorrectly generating an event with the `TRACE` level ([tokio-rs#1930]) - Fixed macro hygiene issues when used in a crate that defines its own `concat!` macro, for real this time ([tokio-rs#1918]) Thanks to @QnnOkabayashi, @nicolaasg, and @teohhanhui for contributing to this release! [tokio-rs#1935]: tokio-rs#1935 [tokio-rs#1913]: tokio-rs#1913 [tokio-rs#1930]: tokio-rs#1930 [tokio-rs#1918]: tokio-rs#1918
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Re-application of changes made in #1842 which were lost in f1cf1f1
Integration tests added for regression.
Motivation
In my library I define a
macro_rules! concatmacro, i.e.callbag::concat.When I try to call
tracing::info!(...), I get error output such asthis:
error output
This is because of my
concatmacro being in scope.Solution
Change all the
tracingmacros to use the re-export ofcore::concat!in the
__macro_supportmodule, rather than using an un-namespacedconcat!. The re-export ensures that everything still works even in acrate that redefines the
corename to something else.