fix: preserve signal-based exit codes (128 + signal_number) (#161)

Author: wolfv

src/shell/commands/executable.rs

@@ -65,11 +65,24 @@ impl ShellCommand for ExecutableCommand {
       loop {
         tokio::select! {
           result = child.wait() => match result {
-            Ok(status) => return ExecuteResult::Continue(
-              status.code().unwrap_or(1),
-              Vec::new(),
-              Vec::new(),
-            ),
+            Ok(status) => {
+              #[cfg(unix)]
+              let exit_code = {
+                use std::os::unix::process::ExitStatusExt;
+                status.code().unwrap_or_else(|| {
+                  // Process was terminated by a signal, return 128 + signal_number per POSIX
+                  status.signal().map(|sig| 128 + sig).unwrap_or(1)
+                })
+              };
+              #[cfg(not(unix))]
+              let exit_code = status.code().unwrap_or(1);
+
+              return ExecuteResult::Continue(
+                exit_code,
+                Vec::new(),
+                Vec::new(),
+              );
+            }
             Err(err) => {
               let _ = stderr.write_line(&format!("{}", err));
               return ExecuteResult::from_exit_code(1);

tests/integration_test.rs

@@ -1631,3 +1631,49 @@ fn no_such_file_error_text() -> &'static str {
     "No such file or directory (os error 2)"
   }
 }
+
+#[tokio::test]
+#[cfg(unix)]
+async fn signal_exit_codes() {
+  // Test SIGPIPE exit code (128 + 13 = 141)
+  TestBuilder::new()
+    .command("sh -c 'kill -PIPE $$'")
+    .assert_exit_code(141)
+    .run()
+    .await;
+
+  // Test SIGTERM exit code (128 + 15 = 143)
+  TestBuilder::new()
+    .command("sh -c 'kill -TERM $$'")
+    .assert_exit_code(143)
+    .run()
+    .await;
+
+  // Test SIGINT exit code (128 + 2 = 130)
+  TestBuilder::new()
+    .command("sh -c 'kill -INT $$'")
+    .assert_exit_code(130)
+    .run()
+    .await;
+
+  // Test SIGKILL exit code (128 + 9 = 137)
+  TestBuilder::new()
+    .command("sh -c 'kill -KILL $$'")
+    .assert_exit_code(137)
+    .run()
+    .await;
+}
+
+#[tokio::test]
+#[cfg(unix)]
+async fn sigpipe_from_pipeline() {
+  // Test that SIGPIPE from a closed pipe doesn't cause issues
+  // and the pipeline completes successfully
+  // `yes` outputs infinite "y\n" until SIGPIPE, `head -n 1` reads one line
+  TestBuilder::new()
+    .command("yes | head -n 1")
+    .assert_stdout("y\n")
+    .assert_exit_code(0)
+    .run()
+    .await;
+}