Instrument(ed) components using the plain tracing::debug_span! macr…

…o instead of using `#[instrument]`

This skips waiting for <tokio-rs/tracing#1819> to land and should also compile a bit faster in some cases.

Cargo.toml

@@ -54,7 +54,7 @@ lignin-schema = { git = "https://github.com/Tamschi/lignin-schema.git", branch =
 rhizome = { version = "0.0.1", features = ["macros"] } # public
 static_assertions = "1.1.0"
 typed-builder = "0.9.0" # semi-public
-tracing = { version = "0.1.29", optional = true, default-features = false, features = ["attributes"] }
+tracing = { version = "0.1.29", optional = true, default-features = false }
 
 [dev-dependencies]
 cargo-husky = "1.5.0"

book/Cargo.toml

@@ -29,7 +29,6 @@ proc-macro2 = "1.0.24" #TODO
 pulldown-cmark = "0.7.0" #TODO
 pulldown-cmark-to-cmark = "5.0.0" #TODO
 quote = "1.0.7"
-tracing = { version = "0.1.29", default-features = false }
 
 [dev-dependencies]
 version-sync = "0.9.1"
@@ -45,4 +44,3 @@ pulldown-cmark = "0.7.0"
 pulldown-cmark-to-cmark = "5.0.0"
 quote = "1.0.7"
 walkdir = "2.3.1"
-tracing = { version = "0.1.29", default-features = false }

proc-macro-definitions/src/component_declaration.rs

@@ -650,18 +650,15 @@ impl ComponentDeclaration {
 			#(#struct_definition)*
 
 			impl#component_impl_generics #component_name#component_type_generics #component_where_clause {
-				#[::#asteracea::__::tracing::instrument(
-					level = "trace",
-					name = #new_span_name,
-					skip_all,
-					fields(#(#constructor_args_tracing_fields,)*),
-				)]
 				#(#constructor_attributes)*
 				pub fn #new#new_generics(
 					parent_node: &::std::sync::Arc<#asteracea::rhizome::Node>,
 					args: #new_args_name#new_args_generic_args,
 				) -> ::std::result::Result<Self, ::#asteracea::error::Escalation> where Self: 'a + 'static { // TODO: Self: 'static is necessary because of `derive_for::<Self>`, but that's not really a good approach... Using derived IDs would be better.
-					// Split off so that `#[instrument]` can see fields.
+					// Tracing's `#[instrument]` macro is slightly unwieldy in terms of compilation.
+					// The following should be equivalent to skipping all fields and setting them one by one:
+					let _tracing_span = ::#asteracea::__::tracing::debug_span!(#new_span_name, #(#constructor_args_tracing_fields,)*).entered();
+
 					let #new_args_name {
 						#(#constructor_args_field_patterns,)*
 						__Asteracea__phantom: _,
@@ -692,19 +689,16 @@ impl ComponentDeclaration {
 					#new_args_name::builder()
 				}
 
-				#[::#asteracea::__::tracing::instrument(
-					level = "trace",
-					name = #render_span_name,
-					skip_all,
-					fields(#(#render_args_tracing_fields,)*),
-				)]
 				#(#render_attributes)*
 				pub fn #render#render_generics(
 					#render_self: ::std::pin::Pin<&'a Self>,
 					#bump: &'bump #asteracea::bumpalo::Bump,
 					args: #render_args_name#render_args_generic_args,
 				) #render_type {
-					// Split off so that `#[instrument]` can see fields.
+					// Tracing's `#[instrument]` macro is slightly unwieldy in terms of compilation.
+					// The following should be equivalent to skipping all fields and setting them one by one:
+					let _tracing_span = ::#asteracea::__::tracing::debug_span!(#new_span_name, #(#render_args_tracing_fields,)*).entered();
+
 					let #render_args_name {
 						#(#render_args_field_patterns,)*
 						__Asteracea__phantom: _,

proc-macro-definitions/src/lib.rs

@@ -11,8 +11,11 @@ use quote::{quote, quote_spanned};
 use std::iter;
 use syn::{
 	parse::{Parse, ParseStream},
-	parse_macro_input, Error, Ident, Result,
+	parse_macro_input,
+	spanned::Spanned,
+	Error, Ident, Result,
 };
+use tap::Conv;
 
 mod component_declaration;
 mod map_message;
@@ -196,3 +199,14 @@ pub fn discard_these_attribute_args(args: TokenStream1, item: TokenStream1) -> T
 	drop(args);
 	item
 }
+
+/// Returns just an `::asteracea::__::tracing::Span`, preserving [`Span`] location but resolving it at [`Span::mixed_site()`](`Span::mixed_site`).
+#[proc_macro]
+pub fn fake_span(input: TokenStream1) -> TokenStream1 {
+	let span = input
+		.conv::<TokenStream2>()
+		.span()
+		.resolved_at(Span::mixed_site());
+	let asteracea = asteracea_ident(span);
+	quote_spanned!(span=> ::#asteracea::__::tracing::Span).into()
+}

src/__.rs

@@ -17,7 +17,15 @@ pub use tracing;
 
 #[cfg(not(feature = "tracing"))]
 pub mod tracing {
-	pub use asteracea_proc_macro_definitions::discard_these_attribute_args as instrument;
+	pub use asteracea_proc_macro_definitions::fake_span as debug_span;
+
+	pub struct Span;
+	impl Span {
+		#[must_use]
+		pub fn entered(self) {
+			drop(self)
+		}
+	}
 }
 
 /// Only implemented for functions that have a signature ABI-compatible with `fn(*const R, T)`!
@@ -78,22 +86,24 @@ impl AnonymousContentParentParametersBuilder {
 /// struct YesDebug;
 /// struct NoDebug;
 ///
-/// #[::asteracea::__::tracing::instrument(skip_all, fields(
-///     value = {
-///         use ::asteracea::__::CoerceTracingValue;
-///         (&&&&::asteracea::__::InertWrapper(&value)).coerce()
-///     },
-///     debug = {
-///         use ::asteracea::__::CoerceTracingValue;
-///         (&&&&::asteracea::__::InertWrapper(&debug_)).coerce()
-///     },
-///     neither = {
-///         use ::asteracea::__::CoerceTracingValue;
-///         (&&&&::asteracea::__::InertWrapper(&neither)).coerce()
-///     },
-/// ))]
-/// //FIXME: `#[instrument]` isn't hygienic, so the parameter can't be called `debug`. See <https://github.com/tokio-rs/tracing/issues/1318>.
+/// //FIXME: `debug_span` isn't entirely hygienic, so the parameter can't be called `debug`.
+/// // See <https://github.com/tokio-rs/tracing/issues/1318>.
 /// pub fn auto_values(value: u32, debug_: YesDebug, neither: NoDebug) {
+///     let _span = ::asteracea::__::tracing::debug_span!(
+///             "auto_values",
+///             value = {
+///                 use ::asteracea::__::CoerceTracingValue;
+///                 (&&&&&::asteracea::__::InertWrapper(&value)).coerce()
+///             },
+///             debug = {
+///                 use ::asteracea::__::CoerceTracingValue;
+///                 (&&&&&::asteracea::__::InertWrapper(&debug_)).coerce()
+///             },
+///             neither = {
+///                 use ::asteracea::__::CoerceTracingValue;
+///                 (&&&&&::asteracea::__::InertWrapper(&neither)).coerce()
+///             },
+///         ).entered();
 ///     drop((value, debug_, neither))
 /// }
 /// ```

src/components/router.rs

@@ -2,7 +2,7 @@
 
 use crate::{
 	error::Escalation,
-	__::{tracing::instrument, Built},
+	__::{tracing::debug_span, Built},
 };
 use ::std::pin::Pin;
 use bumpalo::Bump;
@@ -16,15 +16,14 @@ pub struct Router;
 
 const _: () = {
 	impl Router {
-		#[instrument(name = "Router::new", skip_all)]
 		pub fn new(
 			_parent_node: &Arc<rhizome::Node>,
 			RouterNewArgs {}: RouterNewArgs,
 		) -> Result<Self, Escalation> {
+			let _span = debug_span!("Router::new").entered();
 			Ok(Self)
 		}
 
-		#[instrument(name = "Router::render", skip_all, fields(path = path))]
 		pub fn render<'bump>(
 			self: Pin<&Self>,
 			bump: &'bump Bump,
@@ -34,6 +33,7 @@ const _: () = {
 				rest,
 			}: RouterRenderArgs<'_, 'bump>,
 		) -> Result<Node<'bump, ThreadSafe>, Escalation> {
+			let _span = debug_span!("Router::render", path).entered();
 			for route in __Asteracea__anonymous_content {
 				let (RouterParentParameters { paths }, render_content) = route;
 				for route in paths {