review second round - debug impl output changed to [de ad be ef] and …

…json has its own implementation

tracing-core/src/field.rs

@@ -38,7 +38,7 @@
 use crate::callsite;
 use core::{
     borrow::Borrow,
-    fmt,
+    fmt::{self, Write},
     hash::{Hash, Hasher},
     num,
     ops::Range,
@@ -292,11 +292,19 @@ struct HexBytes<'a>(&'a [u8]);
 
 impl<'a> fmt::Debug for HexBytes<'a> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        for byte in self.0 {
+        f.write_char('[')?;
+
+        let mut bytes = self.0.iter();
+
+        if let Some(byte) = bytes.next() {
             f.write_fmt(format_args!("{byte:02x}"))?;
         }
 
-        Ok(())
+        for byte in bytes {
+            f.write_fmt(format_args!(" {byte:02x}"))?;
+        }
+
+        f.write_char(']')
     }
 }
 
@@ -1173,6 +1181,6 @@ mod test {
             use core::fmt::Write;
             write!(&mut result, "{:?}", value).unwrap();
         });
-        assert_eq!(result, format!("{}", r#"616263" "c0ffee"#));
+        assert_eq!(result, format!("{}", r#"[61 62 63]" "[c0 ff ee]"#));
     }
 }

tracing-subscriber/src/fmt/format/json.rs

@@ -488,6 +488,11 @@ impl<'a> field::Visit for JsonVisitor<'a> {
             .insert(field.name(), serde_json::Value::from(value));
     }
 
+    fn record_bytes(&mut self, field: &Field, value: &[u8]) {
+        self.values
+            .insert(field.name(), serde_json::Value::from(value));
+    }
+
     fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) {
         match field.name() {
             // Skip fields that are actually log metadata that have already been handled
@@ -528,13 +533,19 @@ mod test {
     #[test]
     fn json() {
         let expected =
-        "{\"timestamp\":\"fake time\",\"level\":\"INFO\",\"span\":{\"answer\":42,\"name\":\"json_span\",\"number\":3,\"slice\":\"616263\"},\"spans\":[{\"answer\":42,\"name\":\"json_span\",\"number\":3,\"slice\":\"616263\"}],\"target\":\"tracing_subscriber::fmt::format::json::test\",\"fields\":{\"message\":\"some json test\"}}\n";
+        "{\"timestamp\":\"fake time\",\"level\":\"INFO\",\"span\":{\"answer\":42,\"name\":\"json_span\",\"number\":3,\"slice\":[97,98,99]},\"spans\":[{\"answer\":42,\"name\":\"json_span\",\"number\":3,\"slice\":[97,98,99]}],\"target\":\"tracing_subscriber::fmt::format::json::test\",\"fields\":{\"message\":\"some json test\"}}\n";
         let collector = collector()
             .flatten_event(false)
             .with_current_span(true)
             .with_span_list(true);
         test_json(expected, collector, || {
-            let span = tracing::span!(tracing::Level::INFO, "json_span", answer = 42, number = 3, slice = &b"abc"[..]);
+            let span = tracing::span!(
+                tracing::Level::INFO,
+                "json_span",
+                answer = 42,
+                number = 3,
+                slice = &b"abc"[..]
+            );
             let _guard = span.enter();
             tracing::info!("some json test");
         });