BuildConfig: Want to get values that I set

[schneems]

Currently the values on BuildConfig are pub(crate) so I cannot access values that I've set:

pub struct BuildConfig {
    pub(crate) app_dir: PathBuf,
    pub(crate) cargo_profile: CargoProfile,
    pub(crate) target_triple: String,
    pub(crate) builder_name: String,
    pub(crate) buildpacks: Vec<BuildpackReference>,
    pub(crate) env: HashMap<String, String>,
    pub(crate) app_dir_preprocessor: Option<Rc<dyn Fn(PathBuf)>>,
    pub(crate) expected_pack_result: PackResult,
}

I'm wanting to inspect the builder_name to write logic like https://github.com/heroku/buildpacks-python/blob/de378063c83e1eec6302e79f93f189162b5bbbbf/tests/mod.rs#L31-L38. I would prefer to pass in a BuildConfig to a specific function and return a BuildConfig (or mutate a passed in build config, either way). Currently I cannot do this, because that value is not readable.

Options

• Make the fields pub
• Add get_* associated functions to retrieve set values
• Do nothing, any values desired must be passed into a single function like the Python example above

Additional thoughts

While I'm looking at BuildConfig I think we should also make it Debug in addition to Clone