Function explain_source 

pub fn explain_source(
    graph: &PackageGraph,
    name: &str,
    active_patches: Option<&ActivePatchSet>,
    lockfile: Option<&Lockfile>,
    source_replacements: &SourceReplacementSettings,
) -> Result<SourceExplanation, ExplainError>

Build a SourceExplanation for the named package.

Errors

Propagates ExplainError::PackageNotFound or ExplainError::AmbiguousPackageName from locate_package when name matches no package, or more than one package, in graph.