denoland/deno · error · AnyError

HOME not set

Error message

HOME not set

What it means

During `deno jupyter install`/`uninstall`/`status`, Deno computes the Jupyter user data dir where kernelspecs are written. On macOS it mirrors runtimelib's behavior and uses `$HOME/Library/Jupyter`; if the HOME environment variable is unset there is no way to locate the home directory and the command aborts. A test-only override (DENO_TEST_JUPYTER_PATH) short-circuits the lookup, but production use requires HOME.

Solutions

1. Export HOME before running: `HOME=/Users/me deno jupyter install`, or fix the profile that unsets it
2. For services and cron, set the variable explicitly: systemd `Environment=HOME=...`, `HOME=...` in the crontab, or `ENV HOME=/root` in Dockerfiles
3. In wrapper scripts, default it: `export HOME=${HOME:-/tmp/deno-home}`

Example fix

# before (Dockerfile)
RUN deno jupyter install

# after
ENV HOME=/root
RUN deno jupyter install

if (!Deno.env.get('HOME')) {
  throw new Error('HOME is not set; export it before running deno jupyter install');
}

const hasHome = (): boolean => Deno.env.has('HOME');

When it happens

Trigger: Any `deno jupyter` subcommand that calls get_user_data_dir() on macOS with HOME unset — `env -i deno jupyter install`, launchd agents without a user environment, cron jobs, or CI runners with a scrubbed environment.

Common situations: Minimal CI containers without a login environment; clean-room invocations with `env -i`; service managers that skip loading the user profile; broken shell rc files that unset HOME.

Understand the failure class

Background: "environment variable is not set" and "Missing keys in environment" errors: what missing required env var messages mean and how to fix them — this error's family across 28 libraries.

Related errors

• APPDATA not set
• could not find ' ' .app bundle under (set via )
• Not running in GitHub Actions
• app bundle has no name
• Automatic provenance is only available in GitHub Actions

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/5f52343e4000a946. Report an issue: GitHub.

Appendix: source

Thrown at cli/tools/jupyter/install.rs:73

    }
    let candidate = dir.join(file_name);
    if canonicalize_path(&candidate).is_ok_and(|c| c == target) {
      return candidate;
    }
  }
  current_exe.to_path_buf()
}

fn get_user_data_dir() -> Result<PathBuf, AnyError> {
  if let Some(env_var) = std::env::var_os(TEST_ENV_VAR_NAME) {
    return Ok(PathBuf::from(env_var));
  }
  // Platform-specific Jupyter user data directory (mirrors runtimelib behavior).
  #[cfg(target_os = "macos")]
  {
    let home = std::env::var_os("HOME")
      .map(PathBuf::from)
      .ok_or_else(|| deno_core::anyhow::anyhow!("HOME not set"))?;
    Ok(home.join("Library").join("Jupyter"))
  }
  #[cfg(target_os = "windows")]
  {
    let appdata = std::env::var_os("APPDATA")
      .map(PathBuf::from)
      .ok_or_else(|| deno_core::anyhow::anyhow!("APPDATA not set"))?;
    Ok(appdata.join("jupyter"))
  }
  #[cfg(not(any(target_os = "macos", target_os = "windows")))]
  {
    if let Some(xdg) = std::env::var_os("XDG_DATA_HOME") {
      return Ok(PathBuf::from(xdg).join("jupyter"));
    }
    let home = std::env::var_os("HOME")
      .map(PathBuf::from)
      .ok_or_else(|| deno_core::anyhow::anyhow!("HOME not set"))?;
    Ok(home.join(".local").join("share").join("jupyter"))

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