Preserve AppError backtraces when applying context wrappers

CHANGELOG.md

@@ -9,6 +9,13 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+## [0.24.17] - 2025-11-02
+
+### Fixed
+- Preserve captured backtraces when wrapping `AppError` instances through
+  `ResultExt::context` by sharing the snapshot instead of attempting to clone
+  `std::backtrace::Backtrace`.
+
 ## [0.24.16] - 2025-11-01
 
 ### Fixed

Cargo.toml

@@ -4,7 +4,7 @@
 
 [package]
 name = "masterror"
-version = "0.24.16"
+version = "0.24.17"
 rust-version = "1.90"
 edition = "2024"
 license = "MIT OR Apache-2.0"

README.md

@@ -80,9 +80,9 @@ The build script keeps the full feature snippet below in sync with
 
 ~~~toml
 [dependencies]
-masterror = { version = "0.24.16", default-features = false }
+masterror = { version = "0.24.17", default-features = false }
 # or with features:
-# masterror = { version = "0.24.16", features = [
+# masterror = { version = "0.24.17", features = [
 #   "std", "axum", "actix", "openapi",
 #   "serde_json", "tracing", "metrics", "backtrace",
 #   "sqlx", "sqlx-migrate", "reqwest", "redis",

src/app_error/core.rs

@@ -91,9 +91,9 @@ pub struct ErrorInner {
     pub details:            Option<String>,
     pub source:             Option<Arc<dyn CoreError + Send + Sync + 'static>>,
     #[cfg(feature = "backtrace")]
-    pub backtrace:          Option<Backtrace>,
+    pub backtrace:          Option<Arc<Backtrace>>,
     #[cfg(feature = "backtrace")]
-    pub captured_backtrace: OnceLock<Option<Backtrace>>,
+    pub captured_backtrace: OnceLock<Option<Arc<Backtrace>>>,
     telemetry_dirty:        AtomicBool,
     #[cfg(feature = "tracing")]
     tracing_dirty:          AtomicBool
@@ -110,9 +110,9 @@ const BACKTRACE_STATE_DISABLED: u8 = 2;
 static BACKTRACE_STATE: AtomicU8 = AtomicU8::new(BACKTRACE_STATE_UNSET);
 
 #[cfg(feature = "backtrace")]
-fn capture_backtrace_snapshot() -> Option<Backtrace> {
+fn capture_backtrace_snapshot() -> Option<Arc<Backtrace>> {
     if should_capture_backtrace() {
-        Some(Backtrace::capture())
+        Some(Arc::new(Backtrace::capture()))
     } else {
         None
     }
@@ -321,13 +321,13 @@ impl Error {
 
     #[cfg(feature = "backtrace")]
     fn capture_backtrace(&self) -> Option<&CapturedBacktrace> {
-        if let Some(backtrace) = self.backtrace.as_ref() {
+        if let Some(backtrace) = self.backtrace.as_deref() {
             return Some(backtrace);
         }
 
         self.captured_backtrace
             .get_or_init(capture_backtrace_snapshot)
-            .as_ref()
+            .as_deref()
     }
 
     #[cfg(not(feature = "backtrace"))]
@@ -336,7 +336,7 @@ impl Error {
     }
 
     #[cfg(feature = "backtrace")]
-    fn set_backtrace_slot(&mut self, backtrace: CapturedBacktrace) {
+    fn set_backtrace_slot(&mut self, backtrace: Arc<Backtrace>) {
         self.backtrace = Some(backtrace);
         self.captured_backtrace = OnceLock::new();
     }
@@ -574,6 +574,21 @@ impl Error {
     /// Attach a captured backtrace.
     #[must_use]
     pub fn with_backtrace(mut self, backtrace: CapturedBacktrace) -> Self {
+        #[cfg(feature = "backtrace")]
+        {
+            self.set_backtrace_slot(Arc::new(backtrace));
+        }
+
+        #[cfg(not(feature = "backtrace"))]
+        {
+            self.set_backtrace_slot(backtrace);
+        }
+        self.mark_dirty();
+        self
+    }
+
+    #[cfg(feature = "backtrace")]
+    pub(crate) fn with_shared_backtrace(mut self, backtrace: Arc<Backtrace>) -> Self {
         self.set_backtrace_slot(backtrace);
         self.mark_dirty();
         self
@@ -678,6 +693,18 @@ impl Error {
         self.capture_backtrace()
     }
 
+    #[cfg(feature = "backtrace")]
+    pub(crate) fn backtrace_shared(&self) -> Option<Arc<Backtrace>> {
+        if let Some(backtrace) = self.backtrace.as_ref() {
+            return Some(Arc::clone(backtrace));
+        }
+
+        self.captured_backtrace
+            .get_or_init(capture_backtrace_snapshot)
+            .as_ref()
+            .map(Arc::clone)
+    }
+
     /// Borrow the source if present.
     #[must_use]
     pub fn source_ref(&self) -> Option<&(dyn CoreError + Send + Sync + 'static)> {

src/result_ext.rs

@@ -102,8 +102,11 @@ impl<T, E> ResultExt<T, E> for Result<T, E> {
                         enriched.details = app_err.details.clone();
                     }
                     #[cfg(feature = "backtrace")]
-                    if let Some(backtrace) = app_err.backtrace().cloned() {
-                        enriched = enriched.with_backtrace(backtrace);
+                    let shared_backtrace = app_err.backtrace_shared();
+
+                    #[cfg(feature = "backtrace")]
+                    if let Some(backtrace) = shared_backtrace {
+                        enriched = enriched.with_shared_backtrace(backtrace);
                     }
 
                     enriched.with_context(app_err)