From c4a88ee64a1f459db35181e082273eb6ed310c38 Mon Sep 17 00:00:00 2001
From: Vikram Bhaskaran <vikram.bhaskaran@outlook.com>
Date: Sat, 10 Oct 2026 16:23:43 +1100
Subject: [PATCH] Keep going when the CLI's stdout is closed.

outln! treated a failed write as success and returned immediately, so run and script stopped before --bounce or --save whenever a pipe reader had gone away. A write error is now ignored and the exit code comes from the work itself.
---
 apps/soundcraft-cli/src/main.rs            |   5 +-
 apps/soundcraft-cli/tests/closed_stdout.rs | 124 +++++++++++++++++++++
 2 files changed, 127 insertions(+), 2 deletions(-)
 create mode 100644 apps/soundcraft-cli/tests/closed_stdout.rs

diff --git a/apps/soundcraft-cli/src/main.rs b/apps/soundcraft-cli/src/main.rs
index 2ba9112..9c69978 100644
--- a/apps/soundcraft-cli/src/main.rs
+++ b/apps/soundcraft-cli/src/main.rs
@@ -20,11 +20,12 @@ use soundcraft_engine::Engine;
 use std::io::Write;
 use std::process::ExitCode;
 
-/// Print without panicking on a closed pipe.
+/// Print without panicking on a closed pipe. A write error must not skip later work
+/// such as `--bounce` or `--save`, and must not by itself report success.
 macro_rules! outln {
     ($($t:tt)*) => {{
         let mut o = std::io::stdout().lock();
-        if writeln!(o, $($t)*).is_err() { return ExitCode::SUCCESS; }
+        let _ = writeln!(o, $($t)*);
     }};
 }
 
diff --git a/apps/soundcraft-cli/tests/closed_stdout.rs b/apps/soundcraft-cli/tests/closed_stdout.rs
new file mode 100644
index 0000000..9807423
--- /dev/null
+++ b/apps/soundcraft-cli/tests/closed_stdout.rs
@@ -0,0 +1,124 @@
+//! A closed stdout must not abort `run` or `script` before `--bounce` and `--save`.
+
+use std::process::{Command, Stdio};
+
+fn bin() -> Command {
+    let mut cmd = Command::new(env!("CARGO_BIN_EXE_soundcraft-cli"));
+    cmd.env("SOUNDCRAFT_NO_PREFS", "1");
+    cmd
+}
+
+/// Drop the read end so the child's stdout writes fail with `EPIPE`.
+fn closed_stdout() -> std::process::Stdio {
+    let (reader, writer) = std::io::pipe().expect("pipe");
+    drop(reader);
+    Stdio::from(writer)
+}
+
+fn temp_dir(name: &str) -> std::path::PathBuf {
+    let dir = std::env::temp_dir().join(format!("sc-cli-{name}-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    dir
+}
+
+#[test]
+fn run_with_closed_stdout_still_bounces_and_saves() {
+    let dir = temp_dir("run");
+    let wav = dir.join("mix.wav");
+    let session = dir.join("Synthetic.scraft");
+    let output = bin()
+        .arg("run")
+        .arg("--cmd")
+        .arg(r#"track.new={"name":"Synthetic","count":1,"format":"stereo"}"#)
+        .arg("--bounce")
+        .arg(&wav)
+        .arg("--save")
+        .arg(&session)
+        .arg("--start")
+        .arg("0")
+        .arg("--end")
+        .arg("0.01")
+        .stdout(closed_stdout())
+        .stderr(Stdio::piped())
+        .output()
+        .unwrap();
+    assert!(output.status.success(), "{}", String::from_utf8_lossy(&output.stderr));
+    assert!(wav.is_file(), "bounce was skipped");
+    assert!(session.is_file(), "save was skipped");
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+#[test]
+fn script_with_closed_stdout_still_bounces_and_saves() {
+    let dir = temp_dir("script");
+    let script = dir.join("edit.scraft.txt");
+    std::fs::write(&script, "track.new {\"name\":\"Synthetic\",\"count\":1,\"format\":\"stereo\"}\n").unwrap();
+    let wav = dir.join("mix.wav");
+    let session = dir.join("Synthetic.scraft");
+    let output = bin()
+        .arg("script")
+        .arg(&script)
+        .arg("--bounce")
+        .arg(&wav)
+        .arg("--save")
+        .arg(&session)
+        .arg("--start")
+        .arg("0")
+        .arg("--end")
+        .arg("0.01")
+        .stdout(closed_stdout())
+        .stderr(Stdio::piped())
+        .output()
+        .unwrap();
+    assert!(output.status.success(), "{}", String::from_utf8_lossy(&output.stderr));
+    assert!(wav.is_file());
+    assert!(session.is_file());
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+#[test]
+fn bounce_then_save_with_closed_stdout_writes_the_wav() {
+    let dir = temp_dir("bounce");
+    let wav = dir.join("mix.wav");
+    let session = dir.join("Empty.scraft");
+    let output = bin()
+        .arg("run")
+        .arg("--bounce")
+        .arg(&wav)
+        .arg("--save")
+        .arg(&session)
+        .arg("--start")
+        .arg("0")
+        .arg("--end")
+        .arg("0.01")
+        .stdout(closed_stdout())
+        .stderr(Stdio::piped())
+        .output()
+        .unwrap();
+    assert!(output.status.success(), "{}", String::from_utf8_lossy(&output.stderr));
+    assert!(wav.is_file());
+    assert!(session.is_file());
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
+#[test]
+fn invalid_bounce_destination_still_fails() {
+    let dir = temp_dir("bad-bounce");
+    let missing = dir.join("no-such-dir").join("mix.wav");
+    let output = bin()
+        .arg("run")
+        .arg("--bounce")
+        .arg(&missing)
+        .arg("--start")
+        .arg("0")
+        .arg("--end")
+        .arg("0.01")
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        .output()
+        .unwrap();
+    assert!(!output.status.success(), "a bounce that cannot be written must fail");
+    assert!(!missing.exists());
+    let _ = std::fs::remove_dir_all(&dir);
+}