Implement Termination for error_stack::Report

packages/libs/error-stack/Cargo.toml

@@ -46,6 +46,10 @@ 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};
@@ -617,6 +619,20 @@ 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"))]