subscriber: rename Layer::new_span to on_new_span (#1674)

While we're breaking things, we may as well do this as well.

Closes #630
Closes #662

tracing-error/src/layer.rs

@@ -40,7 +40,7 @@ where
 {
     /// Notifies this layer that a new span was constructed with the given
     /// `Attributes` and `Id`.
-    fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: layer::Context<'_, S>) {
+    fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: layer::Context<'_, S>) {
         let span = ctx.span(id).expect("span must already exist!");
         if span.extensions().get::<FormattedFields<F>>().is_some() {
             return;

tracing-journald/src/lib.rs

@@ -122,7 +122,7 @@ impl<S> tracing_subscriber::Layer<S> for Layer
 where
     S: Subscriber + for<'span> LookupSpan<'span>,
 {
-    fn new_span(&self, attrs: &Attributes, id: &Id, ctx: Context<S>) {
+    fn on_new_span(&self, attrs: &Attributes, id: &Id, ctx: Context<'_, S>) {
         let span = ctx.span(id).expect("unknown span");
         let mut buf = Vec::with_capacity(256);
 

tracing-opentelemetry/benches/trace.rs

@@ -60,7 +60,7 @@ impl<S> tracing_subscriber::Layer<S> for RegistryAccessLayer
 where
     S: tracing_core::Subscriber + for<'span> tracing_subscriber::registry::LookupSpan<'span>,
 {
-    fn new_span(
+    fn on_new_span(
         &self,
         _attrs: &tracing_core::span::Attributes<'_>,
         id: &tracing::span::Id,
@@ -87,7 +87,7 @@ impl<S> tracing_subscriber::Layer<S> for OtelDataLayer
 where
     S: tracing_core::Subscriber + for<'span> tracing_subscriber::registry::LookupSpan<'span>,
 {
-    fn new_span(
+    fn on_new_span(
         &self,
         attrs: &tracing_core::span::Attributes<'_>,
         id: &tracing::span::Id,

tracing-opentelemetry/src/layer.rs

@@ -410,7 +410,7 @@ where
     ///
     /// [OpenTelemetry `Span`]: opentelemetry::trace::Span
     /// [tracing `Span`]: tracing::Span
-    fn new_span(&self, attrs: &Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
+    fn on_new_span(&self, attrs: &Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
         let span = ctx.span(id).expect("Span not found, this is a bug");
         let mut extensions = span.extensions_mut();
 

tracing-subscriber/src/filter/env/mod.rs

@@ -443,7 +443,7 @@ impl<S: Subscriber> Layer<S> for EnvFilter {
         false
     }
 
-    fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, _: Context<'_, S>) {
+    fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, _: Context<'_, S>) {
         let by_cs = try_lock!(self.by_cs.read());
         if let Some(cs) = by_cs.get(&attrs.metadata().callsite()) {
             let span = cs.to_span_match(attrs);

tracing-subscriber/src/filter/layer_filters.rs

@@ -320,9 +320,9 @@ where
         }
     }
 
-    fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, cx: Context<'_, S>) {
+    fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, cx: Context<'_, S>) {
         self.did_enable(|| {
-            self.layer.new_span(attrs, id, cx.with_filter(self.id()));
+            self.layer.on_new_span(attrs, id, cx.with_filter(self.id()));
         })
     }
 

tracing-subscriber/src/fmt/fmt_layer.rs

@@ -557,7 +557,7 @@ where
     E: FormatEvent<S, N> + 'static,
     W: for<'writer> MakeWriter<'writer> + 'static,
 {
-    fn new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>) {
+    fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>) {
         let span = ctx.span(id).expect("Span not found, this is a bug");
         let mut extensions = span.extensions_mut();
 

tracing-subscriber/src/layer/layered.rs

@@ -97,7 +97,7 @@ where
 
     fn new_span(&self, span: &span::Attributes<'_>) -> span::Id {
         let id = self.inner.new_span(span);
-        self.layer.new_span(span, &id, self.ctx());
+        self.layer.on_new_span(span, &id, self.ctx());
         id
     }
 
@@ -233,9 +233,9 @@ where
     }
 
     #[inline]
-    fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
+    fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
-        self.inner.new_span(attrs, id, ctx.clone());
+        self.inner.on_new_span(attrs, id, ctx.clone());
-        self.layer.new_span(attrs, id, ctx);
+        self.layer.on_new_span(attrs, id, ctx);
     }
 
     #[inline]

tracing-subscriber/src/layer/mod.rs

@@ -650,7 +650,7 @@ where
 
     /// Notifies this layer that a new span was constructed with the given
     /// `Attributes` and `Id`.
-    fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
+    fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
         let _ = (attrs, id, ctx);
     }
 
@@ -1089,9 +1089,9 @@ where
     }
 
     #[inline]
-    fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
+    fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
         if let Some(ref inner) = self {
-            inner.new_span(attrs, id, ctx)
+            inner.on_new_span(attrs, id, ctx)
         }
     }
 
@@ -1190,8 +1190,8 @@ feature! {
             }
 
             #[inline]
-            fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
+            fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: Context<'_, S>) {
-                self.deref().new_span(attrs, id, ctx)
+                self.deref().on_new_span(attrs, id, ctx)
             }
 
             #[inline]

tracing-subscriber/src/registry/sharded.rs

@@ -598,7 +598,7 @@ mod tests {
     where
         S: Subscriber + for<'a> LookupSpan<'a>,
     {
-        fn new_span(&self, _: &Attributes<'_>, id: &Id, ctx: Context<'_, S>) {
+        fn on_new_span(&self, _: &Attributes<'_>, id: &Id, ctx: Context<'_, S>) {
             let span = ctx.span(id).expect("Missing span; this is a bug");
             let mut lock = self.inner.lock().unwrap();
             let is_removed = Arc::new(());

tracing-subscriber/src/reload.rs

@@ -77,8 +77,8 @@ where
     }
 
     #[inline]
-    fn new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: layer::Context<'_, S>) {
+    fn on_new_span(&self, attrs: &span::Attributes<'_>, id: &span::Id, ctx: layer::Context<'_, S>) {
-        try_lock!(self.inner.read()).new_span(attrs, id, ctx)
+        try_lock!(self.inner.read()).on_new_span(attrs, id, ctx)
     }
 
     #[inline]

tracing-subscriber/tests/support.rs

@@ -271,7 +271,7 @@ where
         // TODO: it should be possible to expect spans to follow from other spans
     }
 
-    fn new_span(&self, span: &Attributes<'_>, id: &Id, cx: Context<'_, S>) {
+    fn on_new_span(&self, span: &Attributes<'_>, id: &Id, cx: Context<'_, S>) {
         let meta = span.metadata();
         println!(
             "[{}] new_span: name={:?}; target={:?}; id={:?};",