Allow forking from existing loggers

spdlog/benches/compare_with_cpp_spdlog_async.rs

@@ -10,7 +10,12 @@ use test::black_box;
 use clap::Parser;
 use once_cell::sync::Lazy;
 
-use spdlog::{prelude::*, sink::*, Error, SendToChannelError, ThreadPool};
+use spdlog::{
+    error::{Error, SendToChannelError},
+    prelude::*,
+    sink::*,
+    ThreadPool,
+};
 
 required_multi_thread_feature!();
 

spdlog/benches/spdlog_rs.rs

@@ -9,7 +9,12 @@ use test::Bencher;
 
 use once_cell::sync::Lazy;
 
-use spdlog::{prelude::*, sink::*, Error, ErrorHandler, SendToChannelError, ThreadPool};
+use spdlog::{
+    error::{Error, ErrorHandler, SendToChannelError},
+    prelude::*,
+    sink::*,
+    ThreadPool,
+};
 
 required_multi_thread_feature!();
 

spdlog/src/error.rs

@@ -1,6 +1,9 @@
 //! Provides error types.
 
-use std::{fmt, io, result};
+use std::{
+    fmt::{self, Display},
+    io, result,
+};
 
 use atomic::Atomic;
 use static_assertions::const_assert;
@@ -9,6 +12,8 @@ use thiserror::Error;
 #[cfg(feature = "multi-thread")]
 use crate::{sink::Task, RecordOwned};
 
+pub use crate::env_level::EnvLevelError;
+
 /// The error type of this crate.
 #[derive(Error, Debug)]
 #[non_exhaustive]
@@ -76,12 +81,15 @@ pub enum Error {
     #[error("attempted to convert a string that doesn't match an existing log level: {0}")]
     ParseLevel(String),
 
-    /// The variant returned by [`LoggerBuilder::build`] when an error occurs in
-    /// building a logger.
+    /// The variant returned if an error occurs in setting a invalid logger
+    /// name.
+    ///
+    /// See the documentation of [`LoggerBuilder::name`] for the name
+    /// requirements.
     ///
-    /// [`LoggerBuilder::build`]: crate::LoggerBuilder::build
-    #[error("failed to build a logger: {0}")]
-    BuildLogger(BuildLoggerError),
+    /// [`LoggerBuilder::name`]: crate::LoggerBuilder::name
+    #[error("failed to set logger name: {0}")]
+    SetLoggerName(#[from] SetLoggerNameError),
 
     /// The variant returned by [`Sink`]s when an error occurs in sending to the
     /// channel.
@@ -92,18 +100,31 @@ pub enum Error {
     SendToChannel(SendToChannelError, SendToChannelErrorDropped),
 }
 
-/// The more detailed error type of building a logger.
+/// This error indicates that an invalid logger name was set.
+///
+/// See the documentation of [`LoggerBuilder::name`] for the name requirements.
+///
+/// [`LoggerBuilder::name`]: crate::LoggerBuilder::name
 #[derive(Error, Debug)]
-#[non_exhaustive]
-pub enum BuildLoggerError {
-    /// The name of the logger is invalid.
-    ///
-    /// See the documentation of [`LoggerBuilder::name`] for the name
-    /// requirements.
-    ///
-    /// [`LoggerBuilder::name`]: crate::LoggerBuilder::name
-    #[error("invalid logger name: {0}")]
-    InvalidName(String),
+pub struct SetLoggerNameError {
+    name: String,
+}
+
+impl SetLoggerNameError {
+    pub(crate) fn new(name: impl Into<String>) -> Self {
+        Self { name: name.into() }
+    }
+
+    #[cfg(test)]
+    pub(crate) fn name(&self) -> &str {
+        &self.name
+    }
+}
+
+impl Display for SetLoggerNameError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "name '{}' contains disallowed characters", self.name)
+    }
 }
 
 /// The more detailed error type of sending to channel.

spdlog/src/lib.rs

@@ -194,7 +194,7 @@
 #![warn(missing_docs)]
 
 mod env_level;
-mod error;
+pub mod error;
 pub mod formatter;
 mod level;
 #[cfg(feature = "log")]
@@ -215,8 +215,7 @@ mod test_utils;
 mod thread_pool;
 mod utils;
 
-pub use env_level::EnvLevelError;
-pub use error::*;
+pub use error::{Error, ErrorHandler, Result};
 pub use level::*;
 #[cfg(feature = "log")]
 pub use log_crate_proxy::*;
@@ -242,6 +241,7 @@ use std::{
 
 use cfg_if::cfg_if;
 
+use error::EnvLevelError;
 use sink::{
     Sink, {StdStream, StdStreamSink},
 };
@@ -523,16 +523,10 @@ pub fn set_default_logger(logger: Arc<Logger>) {
 ///
 ///   ```
 ///   # std::env::set_var("SPDLOG_RS_LEVEL", "network=Warn,network=Warn");
-///   let result = spdlog::init_env_level();
-///   # // TODO: commented out since `assert_matches` is currently unstable.
-///   # //       change to use `assert_matches` when it is stable.
-///   # // assert_matches!(result, Err(spdlog::EnvLevelError::ParseEnvVar(_)));
-///   if let Err(spdlog::EnvLevelError::ParseEnvVar(_)) = result {
-///       // expected
-///   } else {
-///       // unexpected
-///       assert!(false);
-///   }
+///   assert!(matches!(
+///       spdlog::init_env_level(),
+///       Err(spdlog::error::EnvLevelError::ParseEnvVar(_))
+///   ));
 ///   ```
 pub fn init_env_level() -> StdResult<bool, EnvLevelError> {
     init_env_level_from("SPDLOG_RS_LEVEL")