influxdata/influxdb · warning

expected bucket id, got string

Error message

expected bucket id, got string

What it means

Test helper expect_bucket panics with this message when the enum holds the String variant instead of Bucket. It is a proptest narrowing helper verifying bucketed time partitioning; this panic means a string-formatted column value was produced where a bucket id was expected.

Solutions

1. Ensure the template part under test actually uses bucketing (bucketBy) before calling expect_bucket()
2. Use expect_ts_range()/string expectations for non-bucketed templates
3. Fix fixture construction so ColumnValue::Bucket is produced

Example fix

// before
let (id, num) = got_val.expect_bucket();
// after
match got_val {
    ColumnValue::Bucket{..} => { let (id, num) = got_val.expect_bucket(); }
    ColumnValue::String(_) => { /* string template part — adjust test */ }
    _ => {}
}

assert!(matches!(got_val, ColumnValue::Bucket{..}), "expected Bucket, got {got_val:?}");

fn is_bucket(v: &ColumnValue) -> bool { matches!(v, ColumnValue::Bucket{..}) }

When it happens

Trigger: Calling expect_bucket() on a variant holding ColumnValue::String — e.g. the template part rendered as a plain strftime string rather than being converted to a bucket.

Common situations: Property tests where the fixture template produced string keys instead of bucketed values; forgetting that a template without bucketBy renders strings.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• expected bucket id, got TS range
• expected TS range, got bucket id
• expected datatime column value but got
• expected i64 got
• column id in series key should be valid

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/046c5fb1dacba326. Report an issue: GitHub.

Appendix: source

Thrown at core/partition/src/lib.rs:1535

        fn expect_string(&self) -> &String {
            match self {
                Self::String(s) => s,
                Self::TSRange(_, _) => panic!("expected string, got TS range"),
                Self::Bucket(_, _) => panic!("expected string, got bucket id"),
            }
        }

        fn expect_ts_range(&self) -> (DateTime<Utc>, DateTime<Utc>) {
            match self {
                Self::String(_) => panic!("expected TS range, got string"),
                Self::TSRange(b, e) => (*b, *e),
                Self::Bucket(_, _) => panic!("expected TS range, got bucket id"),
            }
        }

        fn expect_bucket(&self) -> (u32, u32) {
            match self {
                Self::String(_) => panic!("expected bucket id, got string"),
                Self::TSRange(_, _) => panic!("expected bucket id, got TS range"),
                Self::Bucket(id, num_buckets) => (*id, *num_buckets),
            }
        }
    }

    proptest! {
        /// A property test that asserts a write comprised of an arbitrary
        /// subset of [`TEST_TAG_NAME_SET`] with randomised values, that is
        /// partitioned using a partitioning template arbitrarily selected from
        /// [`TEST_TEMPLATE_PARTS`], can be reversed to the full set of tags
        /// and/or hash-bucket IDs via [`build_column_values()`].
        #[test]
        fn prop_reversible_mapping(
            template in arbitrary_template_parts(),
            tag_values in arbitrary_tag_value_map(),
            ts in 0_i64..i64::MAX,
        ) {

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