fn persist_failure_to_file()

in src/runtime/failure.rs [82:107]

• 22 lines of code
• 4 McCabe index (conditional complexity)

fn persist_failure_to_file(serialized_schedule: &str, destination: Option<&PathBuf>) -> std::io::Result<PathBuf> {
    // Try to find the first usable filename. This is quadratic but we don't expect a ton of
    // conflicts here.
    let mut i = 0;
    let dir = if let Some(dir) = destination {
        dir.clone()
    } else {
        std::env::current_dir()?
    };
    let (path, mut file) = loop {
        let path = dir.clone().join(Path::new(&format!("schedule{:03}.txt", i)));
        // `create_new` does the existence check and creation atomically, so this loop ensures that
        // two concurrent tests won't try to persist to the same file.
        match OpenOptions::new().write(true).create_new(true).open(&path) {
            Ok(file) => break (path, file),
            Err(e) => {
                if e.kind() != ErrorKind::AlreadyExists {
                    return Err(e);
                }
            }
        }
        i += 1;
    };
    file.write_all(serialized_schedule.as_bytes())?;
    path.canonicalize()
}