Code RoomUninitialized buffer read

HardPrep Room Coding #1809

Uninitialized buffer read

Code reviewCode quality & reviewSenior–Staff~35 min

Review this Rust function that pre-sizes a buffer before reading into it.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.

0:00 of about 35 min

Mark a line and say what kind of problem it is.0 findings

1use std::io::Read;

2

3fn read_n(mut r: impl Read, n: usize) -> std::io::Result<Vec<u8>> {

4 let mut buf: Vec<u8> = Vec::with_capacity(n);

5 unsafe { buf.set_len(n); }

6 let got = r.read(&mut buf)?;

7 buf.truncate(got);

8 Ok(buf)

9}

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