rustNull / UndefinedEasy

Unwrap on None panic from HashMap lookup

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BugFind the bug and fix the code

What it should do

Lookup key in HashMap or return default 0. Example: extract_map_entry("missing") -> 0

What happens instead

panicked at 'called `Option::unwrap()` on a `None` value'

use std::collections::HashMap;

fn extract_map_entry(key: &str) -> i32 {
    let mut map = HashMap::new();
    map.insert("active", 1);
    // .unwrap() panics if key is not found
    *map.get(key).unwrap()
}

fn main() {
    println!("{}", extract_map_entry("missing"));
}

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

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This bug belongs to the null and undefined errors pattern

Cannot read properties of undefined, NoneType has no attribute, NaN appearing from nowhere.

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use std::collections::HashMap; fn extract_map_entry(key: &str) -> i32 { let mut map = HashMap::new(); map.insert("active", 1); // .unwrap() panics if key is not found *map.get(key).unwrap() } fn main() { println!("{}", extract_map_entry("missing")); }

Unwrap on None panic from HashMap lookup

What it should do

What happens instead

More null and undefined errors to practise

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Unwrap on None panic from HashMap lookup

What it should do

What happens instead

More null and undefined errors to practise

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