Function compile_sync 

pub(crate) fn compile_sync<P: AsRef<Path>>(
    fs: &FileSystem,
    root: P,
    profile: Option<&str>,
    profile_suffix: Option<&str>,
    variables: &BTreeMap<String, String>,
) -> Result<Project, ProjectError>

Compile a project directory into a dependency-aware graph::Project.

This is the canonical synchronous compiler entrypoint. It parses and validates every object for the active profile, reusing cached artifacts when fingerprints still match, and returns a fully-linked project graph with dependency and cross-object validation applied.

See compile_sync_with_stats for the detailed pipeline and cache behavior.