rust.naive_datetime

Correctness Medium

Detects usage of timezone-unaware datetime types that cause subtle bugs.

Why It Matters

Naive datetimes:

• Time zone bugs — Comparisons across zones wrong
• DST issues — Missing/duplicate hours
• Data corruption — Stored times ambiguous

Example

// ❌ Before (naive datetime)
use chrono::NaiveDateTime;

fn schedule_task(at: NaiveDateTime) {
    // What time zone is this in?!
    if at > Utc::now().naive_utc() {
        queue.schedule(at);
    }
}

// ✅ After (timezone-aware datetime)
use chrono::{DateTime, Utc};

fn schedule_task(at: DateTime<Utc>) {
    // Explicit UTC - no ambiguity
    if at > Utc::now() {
        queue.schedule(at);
    }
}

What Unfault Detects

• NaiveDateTime in function signatures
• NaiveDate for scheduling logic
• Missing time zone conversions

Auto-Fix

Unfault can suggest DateTime<Utc> replacements.

Related Rules

• python.naive_datetime