pub fn abs_manifest_path(&self) -> Result<PathBuf> {
        let cwd = self.current_dir()?;
        let path = match &self.manifest_path {
            Some(path) => cwd.join(path),
            None => cwd.join("Cargo.toml"),
        };
        Ok(path.canonicalize()?)
    }
Returns the absolute canonical manifest path.
guppy-cmdlib/src/lib.rs