dbt-labs/dbt-core · error

Versions should not be empty

Error message

Versions should not be empty

What it means

Panic "Versions should not be empty" fires in collect_model_version_info when computing the latest version: the `reduce` on numeric_versions (or the fallback max over version_entries) yields None because the collection is empty despite earlier logic implying at least one entry. It selects the highest numeric version string for a versioned model.

Solutions

1. Guard the empty case: return an error naming the model when version_entries is empty before reducing.
2. Verify the earlier branch condition — if numeric_versions.len() == version_entries.len() and both are 0, reduce panics; require len() > 0 in the condition.
3. Check that the versions YAML block parsed into at least one entry.

Example fix

// before
if numeric_versions.len() == version_entries.len() {
    numeric_versions.iter().reduce(...).expect("Versions should not be empty")
// after
if !numeric_versions.is_empty() && numeric_versions.len() == version_entries.len() {
    numeric_versions.iter().reduce(...).expect("Versions should not be empty")

// in YAML: ensure at least one version entry exists
versions:
  - v: 1
  - v: 2

fn has_versions(entries: &[VersionEntry]) -> bool { !entries.is_empty() }

When it happens

Trigger: A model defines versions where numeric_versions and version_entries end up empty after filtering — e.g., all version entries were filtered out earlier, or `defined_in`/v-defs produced entries that were pruned before this point.

Common situations: YAML with a `versions:` block whose entries are all invalid/non-numeric in an unexpected way; upstream dedup removing every version entry; version parsing changes making numeric_versions.len() == 0 while version_entries also empty.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Adapter must be configured for the parse phase
• Adapter should be available during parse phase
• agate_table
• AgateTable exists
• All snapshot macros should start with 'snapshot_'

AI-assisted analysis of dbt-labs/dbt-core@0267ce9170 (2026-09-07). Data as JSON: /api/errors/0606c046e64aa0ff. Report an issue: GitHub.

Appendix: source

Thrown at crates/dbt-parser/src/resolve/resolve_properties.rs:840

            .clone()
            .map(|v| match v {
                FloatOrString::String(s) => s,
                FloatOrString::Number(n) => n.to_string(),
            })
            .unwrap_or_else(|| {
                // Try parsing as numbers first
                let numeric_versions: Vec<_> = version_entries
                    .iter()
                    .filter_map(|(v, _, _)| v.parse::<f32>().ok())
                    .collect();

                if numeric_versions.len() == version_entries.len() {
                    // If all versions are numeric, use highest number
                    numeric_versions
                        .iter()
                        .reduce(|a, b| if a > b { a } else { b })
                        .map(|n| n.to_string())
                        .expect("Versions should not be empty")
                } else {
                    // Otherwise use lexicographically last
                    version_entries
                        .iter()
                        .map(|(v, _, _)| v)
                        .max()
                        .unwrap()
                        .clone()
                }
            });

        // Find the config for the latest version from existing version entries
        let latest_version_config = version_entries
            .iter()
            .find(|(v, _, _)| v == &latest_version)
            .map(|(_, _, config)| config.clone())
            .unwrap_or_else(|| Verbatim::from(None));

View on GitHub (pinned to 0267ce9170)