diesel-rs/diesel · critical

Maximal supported day interval size is 32 bit

Error message

Maximal supported day interval size is 32 bit

What it means

Diesel's PgInterval stores the `days` field as i32. The `days()` method on interval builder integers converts the caller's integer (commonly i64) via `i32::try_from(self)` and panics with this message if the value does not fit in 32 bits. This is a runtime panic (an .expect), not a recoverable error.

Solutions

1. Validate the day count fits in i32 before calling .days() (value.abs() <= i32::MAX as i64).
2. Break large intervals into months/years: use .months() or .years() for big spans (also i32-bounded but larger effective range).
3. Clamp the interval to the maximum representable days before building the PgInterval.
4. Catch at a higher level: run interval construction behind a checked conversion so invalid input is rejected by app validation, not a panic.

Example fix

// before
let interval = duration_days_i64.days(); // panics if > i32::MAX
// after
let days = i32::try_from(duration_days_i64)
    .map_err(|_| anyhow::anyhow!("interval too large"))?;
let interval = days.days();

fn fits_i32(v: i64) -> bool { v >= i32::MIN as i64 && v <= i32::MAX as i64 }
// guard: if fits_i32(days) { days.days() } else { split into months/years }

fn as_day_count(v: i64) -> Option<i32> { i32::try_from(v).ok() }

// .expect() panics; you cannot catch it. Validate instead:
let days = i32::try_from(raw_days).map_err(|_| Error::IntervalTooLarge)?;
let interval = days.days();

When it happens

Trigger: Calling e.g. `(1i64 << 40).days()` or any value > i32::MAX (2,147,483,647) / < i32::MIN on the interval DSL's days() builder.

Common situations: Computing a day count dynamically (multiplying years by 365 in i64) and passing it to days(); overflow after unit changes from weeks/months to days; user-supplied large durations.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• Unable to perform MySQL global initialization
• not implemented
• DIESEL_MAX_COLUMN_COUNT is a number that fits into a u16
• Using window functions in WHERE clauses is not supported
• Error closing SQLite connection

AI-assisted analysis of diesel-rs/diesel@6fa6ed01b2 (2026-09-07). Data as JSON: /api/errors/e63606b5b44e5456. Report an issue: GitHub.

Appendix: source

Thrown at diesel/src/pg/expression/extensions/interval_dsl.rs:223

    }

    fn minutes(self) -> PgInterval {
        i64::from(self).minutes()
    }

    fn hours(self) -> PgInterval {
        i64::from(self).hours()
    }
}

impl IntervalDsl for i64 {
    fn microseconds(self) -> PgInterval {
        PgInterval::from_microseconds(self)
    }

    fn days(self) -> PgInterval {
        i32::try_from(self)
            .expect("Maximal supported day interval size is 32 bit")
            .days()
    }

    fn months(self) -> PgInterval {
        i32::try_from(self)
            .expect("Maximal supported month interval size is 32 bit")
            .months()
    }
}

#[allow(clippy::cast_possible_truncation)] // we want to truncate
impl IntervalDsl for f64 {
    fn microseconds(self) -> PgInterval {
        (self.round() as i64).microseconds()
    }

    fn days(self) -> PgInterval {
        let fractional_days = (self.fract() * 86_400.0).seconds();

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