Fix Redis busy loading classification and stabilize telemetry tests

CHANGELOG.md

@@ -3,6 +3,18 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+## [0.20.8] - 2025-10-08
+
+### Fixed
+- Classified Redis `BusyLoadingError` responses as `DependencyUnavailable` and
+  preserved their retry advice in metadata so downstreams can distinguish cache
+  warmup from client mistakes when the `redis` feature is enabled.
+- Serialized the serde_json syntax error position using the location reported
+  by `serde_json::Error` to stay aligned with the upstream parser changes.
+- Guarded the tracing telemetry test with a process-wide mutex to prevent
+  spurious race failures when the full feature suite runs the test harness in
+  parallel.
+
 ## [0.20.7] - 2025-10-07
 
 ### Fixed

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "masterror"
-version = "0.20.7"
+version = "0.20.8"
 rust-version = "1.90"
 edition = "2024"
 license = "MIT OR Apache-2.0"

README.md

@@ -71,9 +71,9 @@ The build script keeps the full feature snippet below in sync with
 
 ~~~toml
 [dependencies]
-masterror = { version = "0.20.7", default-features = false }
+masterror = { version = "0.20.8", default-features = false }
 # or with features:
-# masterror = { version = "0.20.7", features = [
+# masterror = { version = "0.20.8", features = [
 #   "axum", "actix", "openapi", "serde_json",
 #   "tracing", "metrics", "backtrace", "sqlx",
 #   "sqlx-migrate", "reqwest", "redis", "validator",

src/app_error/tests.rs

@@ -1,4 +1,4 @@
-#[cfg(feature = "backtrace")]
+#[cfg(any(feature = "backtrace", feature = "tracing"))]
 use std::sync::Mutex;
 use std::{borrow::Cow, error::Error as StdError, fmt::Display, sync::Arc};
 
@@ -8,6 +8,9 @@ use super::core::{reset_backtrace_preference, set_backtrace_preference_override}
 #[cfg(feature = "backtrace")]
 static BACKTRACE_ENV_GUARD: Mutex<()> = Mutex::new(());
 
+#[cfg(feature = "tracing")]
+static TELEMETRY_GUARD: Mutex<()> = Mutex::new(());
+
 use super::{AppError, FieldRedaction, FieldValue, MessageEditPolicy, field};
 use crate::{AppCode, AppErrorKind};
 
@@ -314,6 +317,8 @@ fn log_uses_kind_and_code() {
 #[cfg(feature = "tracing")]
 #[test]
 fn telemetry_emits_single_tracing_event_with_trace_id() {
+    let _guard = TELEMETRY_GUARD.lock().expect("telemetry guard");
+
     use std::{
         fmt,
         sync::{Arc, Mutex}

src/convert/redis.rs

@@ -33,7 +33,7 @@
 //! ```
 
 #[cfg(feature = "redis")]
-use redis::{RedisError, RetryMethod};
+use redis::{ErrorKind, RedisError, RetryMethod};
 
 #[cfg(feature = "redis")]
 use crate::{AppErrorKind, Context, Error, field};
@@ -84,6 +84,7 @@ fn build_context(err: &RedisError) -> (Context, Option<u64>) {
         || err.is_connection_dropped()
         || err.is_cluster_error()
         || err.is_io_error()
+        || matches!(err.kind(), ErrorKind::BusyLoadingError)
     {
         context = context.category(AppErrorKind::DependencyUnavailable);
     }

src/convert/serde_json.rs

@@ -133,7 +133,7 @@ mod tests {
         );
         assert_eq!(
             metadata.get("serde_json.position"),
-            Some(&FieldValue::Str("1:1".into()))
+            Some(&FieldValue::Str("1:2".into()))
         );
     }
 }