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rust.println_in_lib

Maintainability Medium

Detects println!/eprintln! in library code instead of proper logging.

Why It Matters

Print statements in libs:

No log levels — Can’t filter output
No context — Missing timestamps, trace IDs
Pollutes stdout — Interferes with user output

Example

// ❌ Before (raw print in library)
pub fn process(data: &[u8]) -> Result<()> {
    println!("Processing {} bytes", data.len());
    // ...
}

// ✅ After (use tracing or log)
use tracing::debug;

pub fn process(data: &[u8]) -> Result<()> {
    debug!(bytes = data.len(), "Processing data");
    // ...
}

What Unfault Detects

println! in lib.rs or lib crates
eprintln! for error logging
dbg! left in production code

Auto-Fix

Unfault can convert to tracing macros (debug!, info!, warn!, error!).