uutils/coreutils · error

csplit-write-split-not-created

Error message

csplit-write-split-not-created

What it means

This panic occurs in csplit's output writer when a line is about to be written but no current split file writer has been created yet. csplit creates the writer lazily when a split file is opened; writing before any split is open means internal state is inconsistent (the writer was closed or never initialized). It is an unrecoverable panic rather than an io::Error because it indicates a bug in csplit's split-state machine, not user input.

Source

Thrown at src/uu/csplit/src/csplit.rs:303

    /// The current split will not keep any of the read input lines.
    fn as_dev_null(&mut self) {
        self.dev_null = true;
    }

    /// Writes the line to the current split.
    /// If `self.dev_null` is true, then the line is discarded.
    ///
    /// # Errors
    ///
    /// Some [`io::Error`] may occur when attempting to write the line.
    fn writeln(&mut self, line: &str) -> io::Result<()> {
        if !self.dev_null {
            if let Some(ref mut current_writer) = self.current_writer {
                let bytes = line.as_bytes();
                current_writer.write_all(bytes)?;
                self.size += bytes.len();
            } else {
                panic!("{}", translate!("csplit-write-split-not-created"))
            }
        }
        Ok(())
    }

    /// Perform some operations after completing a split, i.e., either remove it
    /// if the [`options::ELIDE_EMPTY_FILES`] option is enabled, or print how much bytes were written
    /// to it if [`options::QUIET`] is disabled.
    ///
    /// # Errors
    ///
    /// Returns an error if flushing the writer fails.
    fn finish_split(&mut self) -> Result<(), CsplitError> {
        if !self.dev_null {
            // Flush the writer to ensure all data is written and errors are detected
            if let Some(ref mut writer) = self.current_writer {
                let file_name = self.options.split_name.get(self.counter - 1);
                writer

View on GitHub (pinned to 9ff4114e82)

Solutions

  1. Update Rust coreutils to the latest version; if reproducible, file a bug with the exact csplit pattern arguments
  2. Check your csplit pattern/script: ensure the first operation opens a split before output is written
  3. Verify the output files were not removed/closed externally mid-run (e.g., another process deleting split files)
  4. As a workaround, redirect output to a directory you control and avoid patterns that address offsets before the first split

Example fix

null
Defensive patterns

Strategy: try-catch

Validate before calling

null

Type guard

null

Try / catch

// panic, not Result — run csplit and check exit status
match Command::new("csplit").args([...]).status() {
    Ok(s) if s.success() => { /* ok */ }
    Ok(s) => eprintln!("csplit failed: {}", s),
    Err(e) => eprintln!("spawn error: {e}"),
}

Prevention

When it happens

Trigger: Internal: writeln() is invoked while self.current_writer is None and dev_null is false — i.e., do_to_line/do_to_match tries to emit output before a split file was opened or after it was finished/removed.

Common situations: Practically only hit with a buggy or patched csplit build, custom pattern scripts whose first operation is a write with no preceding split creation, or corrupted state when the output stream was removed mid-run.

Related errors

AI-assisted analysis of uutils/coreutils@9ff4114e82 (2026-08-31). Data as JSON: /api/errors/2616965456b8514e. Report an issue: GitHub.