zed-industries/zed · error · anyhow::Error

downloaded extension size {actual_len} does not match conten

Error message

downloaded extension size {actual_len} does not match content length {content_length}

What it means

When downloading an extension archive, the host records the Content-Length header (if parseable), streams the body to completion, and then compares the received byte count against it. A mismatch means the body was truncated or altered in transit, and it bails before attempting gzip decompression so the corrupt tarball never reaches disk.

Source

Thrown at crates/extension_host/src/extension_host.rs:822

                .context("error reading extensions")?;

            if response.status().is_client_error() {
                let text = String::from_utf8_lossy(body.as_slice());
                bail!(
                    "status error {}, response: {text:?}",
                    response.status().as_u16()
                );
            }

            let mut response: GetExtensionsResponse = serde_json::from_slice(&body)?;

            response
                .data
                .retain(|extension| !SUPPRESSED_EXTENSIONS.contains(extension.id.as_ref()));

            Ok(response.data)
        })
    }

    pub fn install_extension(
        &mut self,
        extension_id: Arc<str>,
        version: Arc<str>,
        cx: &mut Context<Self>,
    ) {
        self.install_or_upgrade_extension(extension_id, version, ExtensionOperation::Install, cx)
            .detach_and_log_err(cx);
    }

    fn install_or_upgrade_extension_at_endpoint(
        &mut self,
        extension_id: Arc<str>,
        url: Url,
        operation: ExtensionOperation,
        cx: &mut Context<Self>,
    ) -> Task<Result<()>> {

View on GitHub (pinned to 9d272b0363)

Solutions

1. Retry the download — transient truncation is the most common cause.
2. If it persists, verify with `curl -sI <archive-url>` that Content-Length matches what a full `curl -o` download produces.
3. Disable or bypass HTTP-manipulating proxies/VPN and retry.
4. Report to the extension publisher/host if the server itself advertises a wrong Content-Length.

let tar_gz_bytes = retry_with_backoff(3, || async {
    let bytes = download_extension(&client, url).await?;
    if let Some(expected) = content_length {
        anyhow::ensure!(bytes.len() == expected, "truncated download");
    }
    Ok(bytes)
}).await?;

When it happens

Trigger: Connection reset or timeout mid-download; a proxy or antivirus rewriting the body (injecting an error page); server sending a stale/incorrect Content-Length; transparent decompression by an intermediary changing the byte count.

Common situations: Flaky Wi-Fi/VPN links dropping large archive downloads; corporate TLS-inspection proxies; CDN inconsistencies where the header doesn't match the served object; retries after partial failures.

Related errors

• origin/main tip {main_sha[:12]} unavailable locally after fe
• git merge-base --is-ancestor failed
• WSAStartup failed: {}
• Could not fetch Protected Resource Metadata for {}
• Could not fetch Authorization Server Metadata for {}

AI-assisted analysis of zed-industries/zed@9d272b0363 (2026-08-20). Data as JSON: /api/errors/2e3216731666eaed. Report an issue: GitHub.