rust-covfix

Rustc is known to report an incorrect coverage for some lines (https://stackoverflow.com/questions/32521800/why-does-kcov-calculate-incorrect-code-coverage-statistics-for-rust-programs). rust-covfix will read coverage from the file generated by grcov), fix it, then outputs the correct coverage.

Though only lcov format is supprted at current, Another formats is going to be supported in future releases.

Features

• Compatible with latest stable/beta/nightly Rust compiler
• Windows/OSX/Linux are all supprted
• Lightweight (small dependencies)
• Fast and safe (implemented in Rust language)
• rust-covfix is also available with Rust API (Documentation)
• Show summary of coverage difference.

Optional features

Optional features are available with cargo's --features option. You can specify the features like:

$ cargo install --no-default-features --features "cli lcov"

Install

Download the latest release from GitHub Release Page.

You can also install via cargo command.

$ cargo install rust-covfix

Usage

$ rust-covfix --help
Usage:
  rust-covfix [OPTIONS] FILE

Rust coverage fixer

Positional arguments:
  file                  coverage file

Optional arguments:
  -h,--help             Show this help message and exit
  -V,--version          display version
  -v,--verbose          verbose output
  -n,--no-fix           do not fix coverage
  -o,--output FILE      output file name (default: stdout)
  --root DIR            project root directory
  --rules STR[,STR..]   use specified rules to fix coverages. Valid names are
                        [close, test, loop, derive]

How is the incorrect line coverage detected

rust_covfix fixes the coverage information using some rules. You can pass --rules option to specify which rules are used to fix coverages.

Rules

close

closing brackets, line of else block will be ignored.

if a > 0 {
    b = a
} else {  // <-- marked as "not executable"
    b = -a
};  // <-- marked as "not executable"

test

module block named test or tests which has attribute cfg(test) will be ignored

#[cfg(test)]
mod tests {  // <-- removed from coverage
    fn util() { ... }  // <-- removed from coverage

    #[test]
    fn test_hoge() { ... }  // <-- removed from coverage
}

loop

Fix rust internal bugs that loop branches are not correctly passed.

for i in 0..10 {  // <-- fix branch coverage information
    println!("{}", i);
}

derive

structs with derive(...) attribute will be ignored

#[derive(Clone, Debug)]  // <-- removed from coverage
struct Point {  // <-- removed from coverage
  x: f64,  // <-- removed from coverage
  y: f64  // <-- removed from coverage
}  // <-- removed from coverage

comment

ignore coverage based on comment marker

fn main() {
    let a = 1 + 2; // cov:ignore-line

    // cov:begin-ignore-branch
    println!("Hello");
    println!("world!");
    // cov:end-ignore-branch

    // cov: begin-ignore-line
    if a > 2 {
        println!("a is large!");
    } else if a == 0 {
        println!("a is small!");
    }
    // cov: end-ignore-line

    // cov:begin-ignore
    println!("a = {}", a);
    // cov:end-ignore

    println!("finish."); // cov:ignore-branch

    return (); // cov:ignore
}

Roadmap

• Support cobertura.xml file. (WIP)
• Add option for uploading the correct coverages to coveralls.
• Use syntax tree generated using syn crate.
• Performance improvement

Author

👤 Kogia-sima

• Twitter: @Kogia_sima
• Github: @Kogia-sima

🤝 Contributing

Contributions, issues and feature requests are welcome!

Feel free to check issues page.

Show your support

Give a ⭐️ if this project helped you!

📝 License

Copyright © 2019 Kogia-sima.

This project is MIT licensed.

This README was generated with ❤️ by readme-md-generator