Implement Termination for error_stack::Report

packages/libs/error-stack/Cargo.toml

@@ -21,7 +21,9 @@ futures-core = { version = "0.3.21", optional = true, default-features = false }
 [dev-dependencies]
 serde = { version = "1.0.137", features = ["derive"] }
 serde_json = "1.0.81"
-futures = { version = "0.3.21", default-features = false, features = ["executor"] }
+futures = { version = "0.3.21", default-features = false, features = [
+  "executor",
+] }
 
 [build-dependencies]
 rustc_version = "0.2.3"
@@ -35,7 +37,12 @@ futures = ["dep:pin-project"]
 
 [package.metadata.docs.rs]
 all-features = true
-cargo-args = ["-Z", "unstable-options", "-Z", "rustdoc-scrape-examples=examples"]
+cargo-args = [
+  "-Z",
+  "unstable-options",
+  "-Z",
+  "rustdoc-scrape-examples=examples",
+]
 targets = ["x86_64-unknown-linux-gnu"]
 
 [[example]]
@@ -46,6 +53,10 @@ required-features = ["hooks"]
 name = "demo"
 required-features = ["std"]
 
+[[example]]
+name = "exit_code"
+required-features = ["std"]
+
 [[example]]
 name = "parse_config"
 required-features = ["std"]

packages/libs/error-stack/examples/exit_code.rs

@@ -0,0 +1,24 @@
+//! Example of using `attach` to set a custom exit code. Requires nightly and std feature.
+
+use std::process::{ExitCode, Termination};
+
+use error_stack::{Context, Report};
+
+#[derive(Debug)]
+struct CustomError;
+
+impl Context for CustomError {}
+
+impl std::fmt::Display for CustomError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("Custom Error")
+    }
+}
+
+fn main() -> ExitCode {
+    let report = Report::new(CustomError)
+        .attach(ExitCode::from(100))
+        .attach_printable("This error has an exit code of 100!");
+
+    report.report()
+}

packages/libs/error-stack/src/report.rs

@@ -2,6 +2,8 @@ use alloc::{boxed::Box, string::ToString, vec::Vec};
 use core::{fmt, fmt::Write, marker::PhantomData, panic::Location};
 #[cfg(all(nightly, feature = "std"))]
 use std::backtrace::{Backtrace, BacktraceStatus};
+#[cfg(feature = "std")]
+use std::process::ExitCode;
 
 #[cfg(feature = "spantrace")]
 use tracing_error::{SpanTrace, SpanTraceStatus};
@@ -617,10 +619,52 @@ impl<Context> fmt::Debug for Report<Context> {
     }
 }
 
+#[cfg(feature = "std")]
+impl<Context> std::process::Termination for Report<Context> {
+    fn report(self) -> ExitCode {
+        #[cfg(not(nightly))]
+        return ExitCode::FAILURE;
+
+        #[cfg(nightly)]
+        self.request_ref::<ExitCode>()
+            .next()
+            .copied()
+            .unwrap_or(ExitCode::FAILURE)
+    }
+}
+
 pub struct ReportImpl {
     pub(super) frame: Frame,
     #[cfg(all(nightly, feature = "std"))]
     backtrace: Option<Backtrace>,
     #[cfg(feature = "spantrace")]
     span_trace: Option<SpanTrace>,
 }
+#[cfg(test)]
+mod test {
+    use std::process::{ExitCode, Termination};
+
+    use crate::{Context, Report};
+
+    #[derive(Debug)]
+    struct CustomError;
+
+    impl Context for CustomError {}
+
+    impl std::fmt::Display for CustomError {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            f.write_str("Custom Error")
+        }
+    }
+
+    #[test]
+    fn test_exit_code() {
+        let report = Report::new(CustomError)
+            .attach(ExitCode::from(100))
+            .attach_printable("This error has an exit code of 100!");
+
+        // _ to get rid of clippy warning.
+        let _exit = report.report();
+        assert!(matches!(ExitCode::from(100), _exit));
+    }
+}