astral-sh/ruff · error

project directory `{project_path}` does not contain a base n

Error message

project directory `{project_path}` does not contain a base name

What it means

`Task::new` derives each eval task's display name from `project_path.file_name()`; on all platforms `file_name()` returns None only for degenerate paths (`/`, `.`, or paths ending in `..`). Since the path here is the temp copy of a truth fixture directory, this is an internal harness invariant over the truth tree layout rather than a normal user-input error.

Source

Thrown at crates/ty_completion_eval/src/main.rs:277

    db: ProjectDatabase,
    dir: SystemPathBuf,
    name: String,
    cursor: Cursor,
    settings: ty_ide::CompletionSettings,
}

impl Task {
    /// Create a new task for the Python project at `project_path`.
    ///
    /// `truth` should correspond to the completion configuration and the
    /// expected answer for completions at the given `cursor` position.
    fn new(
        project_path: &SystemPath,
        truth: &CompletionTruth,
        cursor: Cursor,
    ) -> anyhow::Result<Task> {
        let name = project_path.file_name().ok_or_else(|| {
            anyhow::anyhow!("project directory `{project_path}` does not contain a base name")
        })?;

        let system = OsSystem::new(project_path);
        let mut project_metadata = ProjectMetadata::discover(project_path, &system)?;
        // Explicitly point ty to the .venv to avoid any set VIRTUAL_ENV variable to take precedence.
        project_metadata.apply_override_options(Options {
            environment: Some(EnvironmentOptions {
                python: Some(RelativePathBuf::cli(".venv")),
                ..EnvironmentOptions::default()
            }),
            ..Options::default()
        });
        let db = ProjectDatabase::fallible(project_metadata, system)?;
        Ok(Task {
            db,
            dir: project_path.to_path_buf(),
            name: name.to_string(),
            cursor,

View on GitHub (pinned to 672bb4edf0)

Solutions

1. Keep truth fixtures as ordinary named subdirectories under `crates/ty_completion_eval/truth/`
2. If hit with an untouched checkout, preserve the command and fixture tree and report it upstream as a harness bug

case "$DIR" in /|.|*..) echo "degenerate project path: $DIR" >&2; exit 2;; esac

When it happens

Trigger: A truth fixture project path that resolves to a root-like or `..`-terminated path — e.g. a fixture created directly at a filesystem root, or harness path handling producing a degenerate path. Practically unreachable with a normal checkout.

Common situations: Exotic truth-tree layouts produced by scripts or manual experimentation; harness bugs after refactoring the temp-copy logic.

Related errors

• truth source directory `{dir}` does not contain a base name
• The current working directory `{}` contains non-Unicode char
• {truth} does not exist: ty's completion evaluation must be r
• truth source directory `{path}` contains invalid UTF-8
• path `{}` is not valid UTF-8

AI-assisted analysis of astral-sh/ruff@672bb4edf0 (2026-08-16). Data as JSON: /api/errors/09eb205e7c3ed90d. Report an issue: GitHub.