gitbutlerapp/gitbutler · error

Could not get app data dir

Error message

Could not get app data dir

What it means

`app_data_dir_for_channel` returns this when `dirs::data_dir()` is None, i.e. the platform data directory cannot be determined. On Linux that means neither `XDG_DATA_HOME` nor a usable home directory (`HOME`, backed by a passwd lookup) exists; on macOS it means no home directory. The `E2E_TEST_APP_DATA_DIR` override short-circuits before this check.

Source

Thrown at crates/but-path/src/lib.rs:55

/// When `E2E_TEST_APP_DATA_DIR` is set, returns `<E2E_TEST_APP_DATA_DIR>/home`
/// so tests never touch the real home directory.
pub fn home_dir() -> Option<PathBuf> {
    if let Some(test_dir) = std::env::var_os("E2E_TEST_APP_DATA_DIR") {
        return Some(PathBuf::from(test_dir).join("home"));
    }
    dirs::home_dir()
}

/// Like [`app_data_dir()`], but explicitly for `channel`.
///
/// When `E2E_TEST_APP_DATA_DIR` is set, `channel` is ignored and the result is always
/// `<E2E_TEST_APP_DATA_DIR>/com.gitbutler.app`.
pub fn app_data_dir_for_channel(channel: AppChannel) -> anyhow::Result<PathBuf> {
    if let Some(test_dir) = std::env::var_os("E2E_TEST_APP_DATA_DIR") {
        return Ok(PathBuf::from(test_dir).join("com.gitbutler.app"));
    }
    dirs::data_dir()
        .ok_or(anyhow::anyhow!("Could not get app data dir"))
        .map(|dir| dir.join(identifier_for_channel(channel)))
}

/// The directory to store logs in, **one per channel**.
///
/// > ⚠️Keep in sync with `tauri::AppHandle::path().app_log_dir().`
///
/// # Platform-specific locations
///
/// - **macOS**: `~/Library/Logs/<identifier()>`
/// - **Linux/Windows/other**: `<data_local_dir>/<identifier()>/logs`
///
/// # Testing behavior
///
/// When the `E2E_TEST_APP_DATA_DIR` environment variable is set (used by E2E tests),
/// this function returns `<E2E_TEST_APP_DATA_DIR>/logs` instead of the platform-specific
/// default directories above. This override always ignores the compile-time channel.
pub fn app_log_dir() -> anyhow::Result<PathBuf> {

View on GitHub (pinned to caf1f223d3)

Solutions

  1. Set `HOME` to a writable directory (or `XDG_DATA_HOME` on Linux) in the failing environment
  2. For tests or hermetic runs, set `E2E_TEST_APP_DATA_DIR` so the check is bypassed entirely
  3. For services, add `Environment="HOME=/var/lib/gitbutler"` (or equivalent) to the unit file
  4. Wrap the call with `.context(...)` including HOME/XDG_DATA_HOME values to make future diagnosis immediate

Example fix

// before
let dir = but_path::app_data_dir()?; // Could not get app data dir

// after
use anyhow::Context;
let dir = but_path::app_data_dir().with_context(|| {
    format!(
        "resolving app data dir (HOME={:?}, XDG_DATA_HOME={:?})",
        std::env::var("HOME"),
        std::env::var("XDG_DATA_HOME")
    )
})?;
Defensive patterns

Strategy: validation

Validate before calling

// Probing what dirs::data_dir() sees, without calling but_path:
fn data_dir_available() -> bool {
    std::env::var_os("XDG_DATA_HOME").is_some() || dirs::home_dir().is_some()
}
// or simply provide the override in tests:
// std::env::set_var("E2E_TEST_APP_DATA_DIR", "/tmp/gb-test");

Try / catch

match but_path::app_data_dir_for_channel(channel) {
    Ok(dir) => { /* ... */ }
    Err(e) => {
        log::error!("no data dir; set HOME or XDG_DATA_HOME ({e:#})");
        return Err(e);
    }
}

Prevention

When it happens

Trigger: Running the app or `but` CLI inside a container/systemd service/cron context where HOME is unset and no passwd entry resolves; a stripped-down environment where `HOME` points to a nonexistent path; CI jobs that clear the environment.

Common situations: Docker containers without USER/HOME setup; systemd services missing `Environment=HOME=...` or running with an empty environment; ssh non-login shells; misconfigured sandboxes.

Related errors

AI-assisted analysis of gitbutlerapp/gitbutler@caf1f223d3 (2026-08-20). Data as JSON: /api/errors/4c9f76f7a6a21d95. Report an issue: GitHub.