What causes "The list of index id patterns may not be empty." in quickwit-oss/quickwit?

Include at least one positive pattern, e.g. combine "*" with negations: ["*", "-myindex*"]

The list of index id patterns may not be empty.

Error message

The list of index id patterns may not be empty.

What it means

Thrown while building a SQL WHERE clause from index id patterns for the PostgreSQL metastore when the resulting positive (non-excluded) pattern list is empty — i.e. every pattern was a negation (leading '-') or empty, so no rows could match.

Source

Thrown at quickwit/quickwit-metastore/src/metastore/postgres/metastore.rs:3135

/// Builds the SQL query that returns indexes matching at least one pattern in
/// `index_id_patterns`, and none of the patterns starting with '-'
///
/// For each pattern, we check whether the pattern is valid and replace `*` by `%`
/// to build a SQL `LIKE` query.
fn build_index_id_patterns_sql_query(index_id_patterns: &[String]) -> anyhow::Result<String> {
    let mut positive_patterns = Vec::new();
    let mut negative_patterns = Vec::new();
    for pattern in index_id_patterns {
        if let Some(negative_pattern) = pattern.strip_prefix('-') {
            negative_patterns.push(negative_pattern.to_string());
        } else {
            positive_patterns.push(pattern);
        }
    }

    if positive_patterns.is_empty() {
        anyhow::bail!("The list of index id patterns may not be empty.");
    }

    if index_id_patterns.iter().any(|pattern| pattern == "*") && negative_patterns.is_empty() {
        return Ok("SELECT * FROM indexes".to_string());
    }

    let mut where_like_query = String::new();
    for (index_id_pattern_idx, index_id_pattern) in positive_patterns.iter().enumerate() {
        validate_index_id_pattern(index_id_pattern, false).map_err(|error| {
            MetastoreError::Internal {
                message: "failed to build list indexes query".to_string(),
                cause: error.to_string(),
            }
        })?;
        if index_id_pattern_idx != 0 {
            where_like_query.push_str(" OR ");
        }
        if index_id_pattern.contains('*') {

View on GitHub (pinned to a39730c5cd)

Solutions

Include at least one positive pattern, e.g. combine "*" with negations: ["*", "-myindex*"]
If excluding only, list the indexes to include explicitly instead
Validate the pattern list in the caller before invoking the metastore query

Example fix

// before
let patterns = vec!["-stale-*".to_string()];
// after
let patterns = vec!["*".to_string(), "-stale-*".to_string()];

Defensive patterns

Strategy: validation

Validate before calling

fn has_positive_pattern(pats: &[String]) -> bool {
    pats.iter().any(|p| !p.is_empty() && !p.starts_with('-'))
}
assert!(has_positive_pattern(&patterns), "need at least one positive pattern");

Try / catch

if patterns.iter().all(|p| p.starts_with('-') || p.is_empty()) {
    patterns.insert(0, "*".to_string());
}
list_indexes(&patterns).await?;

Prevention

Combine negation patterns with "*" when you only want exclusions
Validate pattern lists in the CLI layer before hitting the metastore
Document that all-negative pattern lists are unsupported

When it happens

Trigger: Calling a metastore list/query operation with index_id_patterns consisting only of negative patterns like ["-foo", "-bar"], or all patterns being empty strings.

Common situations: Passing a CLI flag like --index-id-pattern '-myindex*' with no positive pattern; constructing query filters programmatically from empty user input.

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

AI-assisted analysis of quickwit-oss/quickwit@a39730c5cd (2026-09-08). Data as JSON: /api/errors/33b05f7c1d3346c7. Report an issue: GitHub.