zed-industries/zed · error

Stream has ended, callback cant hold the lock

Error message

Stream has ended, callback cant hold the lock

What it means

Asserts in write_out that samples.try_lock() succeeds because the capture stream must have ended before encoding is finalized. Firing means audio callbacks may still be running concurrently — the stream wasn't stopped/dropped before finish() called write_out — so taking the sample buffer would race with the callback.

Source

Thrown at crates/livekit_client/src/record.rs:90

            },
            |err| log::error!("error capturing audio track: {:?}", err),
            Some(Duration::from_millis(100)),
        )
        .context("failed to build input stream")?;

    stream.play()?;
    Ok(stream)
}

fn write_out(
    samples: Arc<Mutex<Vec<i16>>>,
    config: cpal::SupportedStreamConfig,
    path: &Path,
) -> Result<()> {
    let samples = std::mem::take(
        &mut *samples
            .try_lock()
            .expect("Stream has ended, callback cant hold the lock"),
    );
    let samples: Vec<f32> = SampleTypeConverter::<_, f32>::new(samples.into_iter()).collect();
    let mut samples = SamplesBuffer::new(
        NonZero::new(config.channels()).expect("config channel is never zero"),
        NonZero::new(config.sample_rate()).expect("config sample_rate is never zero"),
        samples,
    );
    match rodio::wav_to_file(&mut samples, path) {
        Ok(_) => Ok(()),
        Err(e) => Err(anyhow::anyhow!("Failed to write wav file: {}", e)),
    }
}

View on GitHub (pinned to f4178619ac)

Solutions

1. Drop the cpal Stream before calling write_out/finish to guarantee callbacks ceased
2. Replace try_lock().expect with handling for TryLockError if the lifecycle cannot be strictly ordered
3. Add an explicit stop/pause on the stream and join/sleep until the last callback completes

When it happens

Trigger: Thrown at crates/livekit_client/src/record.rs:90 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/3d4eac39597daffd. Report an issue: GitHub.