astral-sh/uv · error · anyhow::Error

`{}` is not a valid PEP 751 filename: expected `pylock.toml`

Error message

`{}` is not a valid PEP 751 filename: expected `pylock.toml` or `pylock.<name>.toml`, where `<name>` is non-empty and contains no dots

What it means

Error "`{}` is not a valid PEP 751 filename: expected `pylock.toml` or `pylock.<name>.toml`, where `<name>` is non-empty and contains no dots" thrown in astral-sh/uv.

Source

Thrown at crates/uv-requirements/src/sources.rs:61

        } else if path.ends_with("setup.cfg") {
            Ok(Self::SetupCfg(path))
        } else if path.ends_with("environment.yml") {
            Ok(Self::EnvironmentYml(path))
        } else if path
            .file_name()
            .is_some_and(|file_name| file_name.to_str().is_some_and(is_pylock_toml))
        {
            Ok(Self::PylockToml(path))
        } else if path
            .extension()
            .is_some_and(|ext| ext.eq_ignore_ascii_case("py") || ext.eq_ignore_ascii_case("pyw"))
        {
            Ok(Self::Pep723Script(path))
        } else if path
            .extension()
            .is_some_and(|ext| ext.eq_ignore_ascii_case("toml"))
        {
            Err(anyhow::anyhow!(
                "`{}` is not a valid PEP 751 filename: expected `pylock.toml` or `pylock.<name>.toml`, where `<name>` is non-empty and contains no dots",
                path.user_display(),
            ))
        } else if path
            .extension()
            .is_some_and(|ext| ext.eq_ignore_ascii_case("txt") || ext.eq_ignore_ascii_case("in"))
        {
            Ok(Self::RequirementsTxt(path))
        } else if path.extension().is_none() {
            // If we don't have an extension, mark it as extensionless so we can detect
            // the format later (either a PEP 723 script or a requirements.txt file).
            Ok(Self::Extensionless(path))
        } else {
            Ok(Self::RequirementsTxt(path))
        }
    }

    /// Parse a [`RequirementsSource`] from a `requirements.txt` file.

View on GitHub (pinned to f1a42680ff)

When it happens

Trigger: Thrown at crates/uv-requirements/src/sources.rs:61 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of astral-sh/uv@f1a42680ff (2026-08-16). Data as JSON: /api/errors/6e9c610cd916fa69. Report an issue: GitHub.