What causes "Effective URL is missing" in gitbutlerapp/gitbutler?

Update libcurl on the system (and rebuild but-installer so libcurl-sys links the new version).

Effective URL is missing

Error message

Effective URL is missing

What it means

Thrown in release.rs after the libcurl transfer when easy.effective_url() returns Ok(None). libcurl always records the final URL after following redirects, so a None here means the curl handle state is abnormal (transfer not completed on this handle, an unusual libcurl build, or an interrupted transfer). It guards the redirect-validation step that checks the API was not redirected off app.gitbutler.com.

Source

Thrown at crates/but-installer/src/release.rs:71

                bail!(
                    "Failed to fetch release information for version {version}. Version may not exist. HTTP {response_code}"
                );
            }
            crate::config::VersionRequest::Nightly => {
                bail!("Failed to fetch nightly release information. HTTP {response_code}");
            }
            crate::config::VersionRequest::Release => {
                bail!("Failed to fetch release information from {url}. HTTP {response_code}");
            }
        }
    }

    // Validate the effective URL after following redirects
    // This protects against malicious redirects to untrusted domains or insecure protocols
    let effective_url = easy
        .effective_url()
        .context("Failed to get effective URL")?
        .ok_or_else(|| anyhow!("Effective URL is missing"))?;

    validate_api_url(effective_url).with_context(|| {
        format!("Release API was redirected to an untrusted URL: {effective_url}")
    })?;

    let release: Release =
        serde_json::from_slice(&response_data).context("Failed to parse release information")?;

    // Verify we got the version we requested (skip check for nightly)
    if let crate::config::VersionRequest::Specific(ref requested) = config.version_request
        && release.version != requested.as_str()
    {
        bail!(
            "API returned version {} but requested version {}",
            release.version,
            requested
        );
    }

View on GitHub (pinned to caf1f223d3)

Solutions

Update libcurl on the system (and rebuild but-installer so libcurl-sys links the new version).
Check for HTTP_PROXY/HTTPS_PROXY interference and retry without the proxy.
Retry the command — a one-off None can follow an interrupted transfer.
Report to GitButler with your libcurl version if it persists on a current curl.

Defensive patterns

Strategy: retry

Try / catch

match fetch_release(&config) {
    Ok(r) if std::env::var("GB_SKIP_REDIRECT_CHECK").is_err() => Ok(r),
    Ok(r) => Ok(r),
    Err(e) if e.to_string().contains("Effective URL is missing") => {
        // environment defect: verify libcurl version, then retry once
        Err(e)
    },
    Err(e) => Err(e),
}

Prevention

Keep system libcurl current on hosts running the installer.
Rule out proxies that interrupt transfers before blaming the API.
Capture the libcurl version in bug reports for this error.

When it happens

Trigger: A libcurl/libcurl-sys version that does not populate CURLINFO_EFFECTIVE_URL after the performed request; the transfer being reset or the handle reused abnormally between perform and query; exotic TLS/proxy middleboxes breaking the transfer's completion state.

Common situations: Systems with unusual or outdated libcurl builds (some minimal distros, containers with old curl); almost never seen on standard setups — treat as an environment/toolchain defect rather than a GitButler-side problem.

Related errors

AI-assisted analysis of gitbutlerapp/gitbutler@caf1f223d3 (2026-08-20). Data as JSON: /api/errors/3086de33e2a75cdd. Report an issue: GitHub.