Feature `cloud` must be enabled to use globbing patterns…

Error message

Feature `cloud` must be enabled to use globbing patterns with cloud urls.

What it means

expand_paths_hive panics when a globbing pattern (e.g. s3://bucket/data/*.parquet) is used with a cloud URL but the polars 'cloud' feature is disabled, since cloud path expansion requires that feature. The library deliberately aborts instead of silently mis-expanding.

Solutions

Enable the cloud feature: polars = { version = "...", features = ["cloud"] } in Cargo.toml.
Remove the wildcard and pass explicit object paths instead (list files yourself via the cloud SDK).
Use local paths for globbing if cloud access is not actually required.

Example fix

// before
polars = { version = "0.46", features = ["lazy"] }
// after
polars = { version = "0.46", features = ["lazy", "cloud"] }

Defensive patterns

Strategy: validation

Validate before calling

fn is_cloud_glob(path: &str) -> bool {
    (path.starts_with("s3://") || path.starts_with("gs://") || path.starts_with("az://") || path.starts_with("azure://"))
        && path.chars().any(|c| c == '*' || c == '?' || c == '[')
}
assert!(!paths.iter().any(is_cloud_glob), "cloud globbing needs the 'cloud' feature");

Try / catch

// It's a panic, not a Result; pre-validate inputs before calling expand_paths
if is_cloud_glob(&url) {
    // list objects via cloud SDK instead, or compile with the cloud feature
}

Prevention

Enable features = ["cloud"] whenever any scan path may point at object storage
Enumerate cloud object lists with the SDK and pass explicit paths when globbing isn't available
Add a startup check that maps intended inputs to required features in CI

When it happens

Trigger: Calling expand_paths / expand_paths_hive (directly or via scan/read functions) with a glob pattern in a cloud scheme URL (s3://, gs://, azure://...) on a polars build compiled without feature = "cloud".

Common situations: Using prebuilt polars wheels/binaries without the cloud feature while scanning wildcards on S3/GCS/Azure; upgrading polars and losing the feature flag in Cargo.toml.

Related errors

AI-assisted analysis of pola-rs/polars@fe841f959e (2026-09-18). Data as JSON: /api/errors/6797ead9d397ddc7. Report an issue: GitHub.

Appendix: source

Thrown at crates/polars-io/src/path_utils/mod.rs:541

                        first_path_has_scheme,
                    )
                    .await?;
                    for (p, size) in paths {
                        if let Some(size) = size {
                            sizes_by_path.insert(p.clone(), size);
                        }
                        out_paths.push(p);
                    }
                    hive_idx_tracker.update(expand_start_idx, path_idx)?;
                };

                if let Some(mut_slice) = out_paths.paths.get_mut(sort_start_idx..) {
                    <[PlRefPath]>::sort_unstable(mut_slice);
                }
            }
        }
        #[cfg(not(feature = "cloud"))]
        panic!("Feature `cloud` must be enabled to use globbing patterns with cloud urls.")
    } else {
        let mut stack: VecDeque<Cow<'_, Path>> = VecDeque::new();
        let mut paths_scratch: Vec<PathBuf> = vec![];

        for (path_idx, path) in paths.iter().enumerate() {
            stack.clear();
            let sort_start_idx = out_paths.paths.len();

            if path.as_std_path().is_dir() {
                let i = path.as_str().len();

                hive_idx_tracker.update(i, path_idx)?;

                stack.push_back(Cow::Borrowed(path.as_std_path()));

                while let Some(dir) = stack.pop_front() {
                    let mut last_err = Ok(());

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