@return [Boolean] where the requirement of the state we’re unwinding
to directly caused the conflict. Note: in this case, it is impossible for the state we're unwinding to to be a parent of any of the other conflicting requirements (or we would have circularity)
Filter’s a state’s possibilities to remove any that would (eventually) create a requirement in the conflict we’ve just rewound from @param [UnwindDetails] unwind_details details of the conflict just unwound from @return [void]
Attempts to update the existing vertex’s ‘PossibilitySet` with a filtered version @return [void]
Pushes a new {DependencyState}. If the {#specification_provider} says to {SpecificationProvider#allow_missing?} that particular requirement, and there are no possibilities for that requirement, then ‘state` is not pushed, and the vertex in {#activated} is removed, and we continue resolving the remaining requirements. @param [DependencyState] state @return [void]
Ensures any raised {NoSuchDependencyError} has its {NoSuchDependencyError#required_by} set. @yield