fn build_package()

in tools/buildsys/src/main.rs [120:181]
47 lines of code
9 McCabe index (conditional complexity)

fn build_package() -> Result<()> {
    let manifest_file = "Cargo.toml";
    println!("cargo:rerun-if-changed={}", manifest_file);

    let root_dir: PathBuf = getenv("BUILDSYS_ROOT_DIR")?.into();
    let variant = getenv("BUILDSYS_VARIANT")?;
    let variant_manifest_path = root_dir.join("variants").join(variant).join(manifest_file);
    let variant_manifest =
        ManifestInfo::new(variant_manifest_path).context(error::ManifestParse)?;
    supported_arch(&variant_manifest)?;

    let manifest_dir: PathBuf = getenv("CARGO_MANIFEST_DIR")?.into();
    let manifest =
        ManifestInfo::new(manifest_dir.join(manifest_file)).context(error::ManifestParse)?;

    // if manifest has package.metadata.build-package.variant-specific = true, then println rerun-if-env-changed
    if let Some(sensitive) = manifest.variant_sensitive() {
        if sensitive {
            println!("cargo:rerun-if-env-changed=BUILDSYS_VARIANT");
        }
    }

    if let Some(files) = manifest.external_files() {
        LookasideCache::fetch(&files).context(error::ExternalFileFetch)?;
    }

    if let Some(groups) = manifest.source_groups() {
        let var = "BUILDSYS_SOURCES_DIR";
        let root: PathBuf = getenv(var)?.into();
        println!("cargo:rerun-if-env-changed={}", var);

        let dirs = groups.iter().map(|d| root.join(d)).collect::<Vec<_>>();
        let info = ProjectInfo::crawl(&dirs).context(error::ProjectCrawl)?;
        for f in info.files {
            println!("cargo:rerun-if-changed={}", f.display());
        }
    }

    // Package developer can override name of package if desired, e.g. to name package with
    // characters invalid in Cargo crate names
    let package = if let Some(name_override) = manifest.package_name() {
        name_override.clone()
    } else {
        getenv("CARGO_PKG_NAME")?
    };
    let spec = format!("{}.spec", package);
    println!("cargo:rerun-if-changed={}", spec);

    let info = SpecInfo::new(PathBuf::from(&spec)).context(error::SpecParse)?;

    for f in info.sources {
        println!("cargo:rerun-if-changed={}", f.display());
    }

    for f in info.patches {
        println!("cargo:rerun-if-changed={}", f.display());
    }

    PackageBuilder::build(&package).context(error::BuildAttempt)?;

    Ok(())
}