From 9ec8130eb7a67504ce531d124bff28b464d92fa8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Teo=20Klestrup=20R=C3=B6ijezon?= <teo@nullable.se>
Date: Thu, 10 Jun 2021 00:39:42 +0200
Subject: [PATCH] Migrate layer crates to use SpanRef::scope

---
 tracing-error/src/layer.rs  |  3 +--
 tracing-flame/src/lib.rs    | 20 ++++++++------------
 tracing-journald/src/lib.rs | 10 +++++++---
 3 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/tracing-error/src/layer.rs b/tracing-error/src/layer.rs
index 05e50c7d86..911d567414 100644
--- a/tracing-error/src/layer.rs
+++ b/tracing-error/src/layer.rs
@@ -90,8 +90,7 @@ where
         let span = subscriber
             .span(id)
             .expect("registry should have a span for the current ID");
-        let parents = span.parents();
-        for span in std::iter::once(span).chain(parents) {
+        for span in span.scope().from_root() {
             let cont = if let Some(fields) = span.extensions().get::<FormattedFields<F>>() {
                 f(span.metadata(), fields.fields.as_str())
             } else {
diff --git a/tracing-flame/src/lib.rs b/tracing-flame/src/lib.rs
index e307d09e9b..6f7523715a 100644
--- a/tracing-flame/src/lib.rs
+++ b/tracing-flame/src/lib.rs
@@ -398,12 +398,10 @@ where
 
         let first = ctx.span(id).expect("expected: span id exists in registry");
 
-        if !self.config.empty_samples && first.from_root().count() == 0 {
+        if !self.config.empty_samples && first.parent().is_none() {
             return;
         }
 
-        let parents = first.from_root();
-
         let mut stack = String::new();
 
         if !self.config.threads_collapsed {
@@ -412,7 +410,11 @@ where
             stack += "all-threads";
         }
 
-        for parent in parents {
+        let mut parents = first.scope();
+        parents
+            .next()
+            .expect("expected: scope begins with leaf scope");
+        for parent in parents.from_root() {
             stack += "; ";
             write(&mut stack, parent, &self.config).expect("expected: write to String never fails");
         }
@@ -444,7 +446,6 @@ where
 
         let samples = self.time_since_last_event();
         let first = expect!(ctx.span(&id), "expected: span id exists in registry");
-        let parents = first.from_root();
 
         let mut stack = String::new();
         if !self.config.threads_collapsed {
@@ -452,20 +453,15 @@ where
         } else {
             stack += "all-threads";
         }
-        stack += "; ";
 
-        for parent in parents {
+        for parent in first.scope().from_root() {
+            stack += "; ";
             expect!(
                 write(&mut stack, parent, &self.config),
                 "expected: write to String never fails"
             );
-            stack += "; ";
         }
 
-        expect!(
-            write(&mut stack, first, &self.config),
-            "expected: write to String never fails"
-        );
         expect!(
             write!(&mut stack, " {}", samples.as_nanos()),
             "expected: write to String never fails"
diff --git a/tracing-journald/src/lib.rs b/tracing-journald/src/lib.rs
index 8b3cfaed56..db3b78ccf3 100644
--- a/tracing-journald/src/lib.rs
+++ b/tracing-journald/src/lib.rs
@@ -126,7 +126,7 @@ where
         let span = ctx.span(id).expect("unknown span");
         let mut buf = Vec::with_capacity(256);
 
-        let depth = span.parents().count();
+        let depth = span.scope().skip(1).count();
 
         writeln!(buf, "S{}_NAME", depth).unwrap();
         put_value(&mut buf, span.name().as_bytes());
@@ -143,7 +143,7 @@ where
 
     fn on_record(&self, id: &Id, values: &Record, ctx: Context<S>) {
         let span = ctx.span(id).expect("unknown span");
-        let depth = span.parents().count();
+        let depth = span.scope().skip(1).count();
         let mut exts = span.extensions_mut();
         let buf = &mut exts.get_mut::<SpanFields>().expect("missing fields").0;
         values.record(&mut SpanVisitor {
@@ -157,7 +157,11 @@ where
         let mut buf = Vec::with_capacity(256);
 
         // Record span fields
-        for span in ctx.scope() {
+        for span in ctx
+            .lookup_current()
+            .into_iter()
+            .flat_map(|span| span.scope())
+        {
             let exts = span.extensions();
             let fields = exts.get::<SpanFields>().expect("missing fields");
             buf.extend_from_slice(&fields.0);