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Document read_line gotchas #106352

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Merged
merged 2 commits into from
Jan 2, 2023
Merged

Document read_line gotchas #106352

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1a98353
Document read_line gotcha
kornelski Jan 1, 2023
3a6ceeb
Document a way to limit read_line length
kornelski Jan 1, 2023
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10 changes: 7 additions & 3 deletions library/std/src/io/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2137,8 +2137,10 @@ pub trait BufRead: Read {
}

/// Read all bytes until a newline (the `0xA` byte) is reached, and append
/// them to the provided buffer. You do not need to clear the buffer before
/// appending.
/// them to the provided `String` buffer.
///
/// Previous content of the buffer will be preserved. To avoid appending to
/// the buffer, you need to [`clear`] it first.
///
/// This function will read bytes from the underlying stream until the
/// newline delimiter (the `0xA` byte) or EOF is found. Once found, all bytes
Expand All @@ -2151,9 +2153,11 @@ pub trait BufRead: Read {
///
/// This function is blocking and should be used carefully: it is possible for
/// an attacker to continuously send bytes without ever sending a newline
/// or EOF.
/// or EOF. You can use [`take`] to limit the maximum number of bytes read.
///
/// [`Ok(0)`]: Ok
/// [`clear`]: String::clear
/// [`take`]: crate::io::Read::take
///
/// # Errors
///
Expand Down