fix(cli): exit quietly when output pipes close (#2996)

refs #2994

Co-authored-by: akbash-bot <300245827+akbash-bot@users.noreply.github.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/broken_pipe.rs b/tests/broken_pipe.rs
new file mode 100644
index 00000000..66aa029e
--- /dev/null
+++ b/tests/broken_pipe.rs
@@ -0,0 +1,49 @@
+#![cfg(unix)]
+
+use std::os::fd::{FromRawFd, OwnedFd};
+use std::os::unix::process::ExitStatusExt;
+use std::process::{Command, Output, Stdio};
+
+fn closed_pipe_writer() -> Stdio {
+    let mut fds = [-1; 2];
+    assert_eq!(unsafe { libc::pipe(fds.as_mut_ptr()) }, 0);
+    // SAFETY: pipe initialized both descriptors, and each is assigned to one
+    // OwnedFd so it is closed exactly once.
+    let read_fd = unsafe { OwnedFd::from_raw_fd(fds[0]) };
+    let write_fd = unsafe { OwnedFd::from_raw_fd(fds[1]) };
+    drop(read_fd);
+    Stdio::from(write_fd)
+}
+
+fn run_with_closed_stdout(args: &[&str]) -> Output {
+    Command::new(env!("CARGO_BIN_EXE_herdr"))
+        .args(args)
+        .stdout(closed_pipe_writer())
+        .stderr(Stdio::piped())
+        .output()
+        .expect("run herdr CLI")
+}
+
+fn assert_quiet_sigpipe(output: Output) {
+    assert_eq!(output.status.signal(), Some(libc::SIGPIPE));
+    assert!(
+        output.stderr.is_empty(),
+        "closed stdout should not emit an error or panic: {}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+}
+
+#[test]
+fn cli_exits_via_sigpipe_without_panicking_when_stdout_closes() {
+    assert_quiet_sigpipe(run_with_closed_stdout(&["api", "schema", "--json"]));
+}
+
+#[test]
+fn terminal_help_uses_cli_sigpipe_behavior_before_attach_starts() {
+    assert_quiet_sigpipe(run_with_closed_stdout(&["terminal", "attach", "--help"]));
+}
+
+#[test]
+fn completion_direct_writer_uses_cli_sigpipe_behavior() {
+    assert_quiet_sigpipe(run_with_closed_stdout(&["completion", "bash"]));
+}