Don't automatically enable tracing for fs feature

tower-http/Cargo.toml

@@ -88,7 +88,7 @@ auth = ["base64", "validate-request"]
 catch-panic = ["tracing", "futures-util/std", "dep:http-body", "dep:http-body-util"]
 cors = []
 follow-redirect = ["futures-util", "dep:http-body", "iri-string", "tower/util"]
-fs = ["futures-core", "futures-util", "dep:http-body", "dep:http-body-util", "tokio/fs", "tokio-util/io", "tokio/io-util", "dep:http-range-header", "mime_guess", "mime", "percent-encoding", "httpdate", "set-status", "futures-util/alloc", "tracing"]
+fs = ["futures-core", "futures-util", "dep:http-body", "dep:http-body-util", "tokio/fs", "tokio-util/io", "tokio/io-util", "dep:http-range-header", "mime_guess", "mime", "percent-encoding", "httpdate", "set-status", "futures-util/alloc"]
 limit = ["dep:http-body", "dep:http-body-util"]
 map-request-body = []
 map-response-body = []

tower-http/src/services/fs/serve_dir/mod.rs

@@ -255,7 +255,8 @@ impl<F> ServeDir<F> {
     /// By default `<ServeDir as Service<_>>::call` will handle IO errors and convert them into
     /// responses. It does that by converting [`std::io::ErrorKind::NotFound`] and
     /// [`std::io::ErrorKind::PermissionDenied`] to `404 Not Found` and any other error to `500
-    /// Internal Server Error`. The error will also be logged with `tracing`.
+    /// Internal Server Error`. The error will also be logged with `tracing` in case the `tracing`
+    /// crate feature is enabled.
     ///
     /// If you want to manually control how the error response is generated you can make a new
     /// service that wraps a `ServeDir` and calls `try_call` instead of `call`.
@@ -411,7 +412,10 @@ where
             .try_call(req)
             .map(|result: Result<_, _>| -> Result<_, Infallible> {
                 let response = result.unwrap_or_else(|err| {
+                    #[cfg(feature = "tracing")]
                     tracing::error!(error = %err, "Failed to read file");
+                    #[cfg(not(feature = "tracing"))]
+                    let _ = err;
 
                     let body = ResponseBody::new(UnsyncBoxBody::new(
                         Empty::new().map_err(|err| match err {}).boxed_unsync(),

tower-http/src/services/fs/serve_dir/open_file.rs

@@ -349,7 +349,11 @@ fn append_slash_on_path(uri: Uri) -> Result<Uri, OpenFileOutput> {
     };
 
     uri_builder.build().map_err(|err| {
+        #[cfg(feature = "tracing")]
         tracing::error!(?err, "redirect uri failed to build");
+        #[cfg(not(feature = "tracing"))]
+        let _ = err;
+
         OpenFileOutput::InvalidRedirectUri
     })
 }