Builds a repo dependency graph from the repo requirements expressed in the `project.yml` file.

Produces an error describing the specified set of repo conflicts.

PruneDepGraph removes all entries from a depgraph that aren't in the given repo slice.

ResolveRepoDeps calculates the set of repo versions a project should be upgraded to.

Indicates dependencies on different versions of the same repo.

A single node in a repo reverse dependency graph.

Represents a repo-name,version pair.

A repo dependency graph.

[repo-name] => repo.

[repo-name] => requirements-for-key-repo.

A repo reverse dependency graph.

[repo-name] => repo-version.