# frozen_string_literal: true
module Bundler::Molinillo
class Resolver
# A specific resolution from a given {Resolver}
class Resolution
# A conflict that the resolution process encountered
# @attr [Object] requirement the requirement that immediately led to the conflict
# @attr [{String,Nil=>[Object]}] requirements the requirements that caused the conflict
# @attr [Object, nil] existing the existing spec that was in conflict with
# the {#possibility}
# @attr [Object] possibility_set the set of specs that was unable to be
# activated due to a conflict.
# @attr [Object] locked_requirement the relevant locking requirement.
# @attr [Array<Array<Object>>] requirement_trees the different requirement
# trees that led to every requirement for the conflicting name.
# @attr [{String=>Object}] activated_by_name the already-activated specs.
# @attr [Object] underlying_error an error that has occurred during resolution, and
# will be raised at the end of it if no resolution is found.
Conflict = Struct.new(
:requirement,
:requirements,
:existing,
:possibility_set,
:locked_requirement,
:requirement_trees,
:activated_by_name,
:underlying_error
)
class Conflict
# @return [Object] a spec that was unable to be activated due to a conflict
def possibility
possibility_set && possibility_set.latest_version
end
end
# A collection of possibility states that share the same dependencies
# @attr [Array] dependencies the dependencies for this set of possibilities
# @attr [Array] possibilities the possibilities
PossibilitySet = Struct.new(:dependencies, :possibilities)
class PossibilitySet
# String representation of the possibility set, for debugging
def to_s
"[#{possibilities.join(', ')}]"
end
# @return [Object] most up-to-date dependency in the possibility set
def latest_version
possibilities.last
end
end
# Details of the state to unwind to when a conflict occurs, and the cause of the unwind
# @attr [Integer] state_index the index of the state to unwind to
# @attr [Object] state_requirement the requirement of the state we're unwinding to
# @attr [Array] requirement_tree for the requirement we're relaxing
# @attr [Array] conflicting_requirements the requirements that combined to cause the conflict
# @attr [Array] requirement_trees for the conflict
# @attr [Array] requirements_unwound_to_instead array of unwind requirements that were chosen over this unwind
UnwindDetails = Struct.new(
:state_index,
:state_requirement,
:requirement_tree,
:conflicting_requirements,
:requirement_trees,
:requirements_unwound_to_instead
)
class UnwindDetails
include Comparable
# We compare UnwindDetails when choosing which state to unwind to. If
# two options have the same state_index we prefer the one most
# removed from a requirement that caused the conflict. Both options
# would unwind to the same state, but a `grandparent` option will
# filter out fewer of its possibilities after doing so - where a state
# is both a `parent` and a `grandparent` to requirements that have
# caused a conflict this is the correct behaviour.
# @param [UnwindDetail] other UnwindDetail to be compared
# @return [Integer] integer specifying ordering
def <=>(other)
if state_index > other.state_index
1
elsif state_index == other.state_index
reversed_requirement_tree_index <=> other.reversed_requirement_tree_index
else
-1
end
end
# @return [Integer] index of state requirement in reversed requirement tree
# (the conflicting requirement itself will be at position 0)
def reversed_requirement_tree_index
@reversed_requirement_tree_index ||=
if state_requirement
requirement_tree.reverse.index(state_requirement)
else
999_999
end
end
# @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)
def unwinding_to_primary_requirement?
requirement_tree.last == state_requirement
end
# @return [Array] array of sub-dependencies to avoid when choosing a
# new possibility for the state we've unwound to. Only relevant for
# non-primary unwinds
def sub_dependencies_to_avoid
@requirements_to_avoid ||=
requirement_trees.map do |tree|
index = tree.index(state_requirement)
tree[index + 1] if index
end.compact
end
# @return [Array] array of all the requirements that led to the need for
# this unwind
def all_requirements
@all_requirements ||= requirement_trees.flatten(1)
end
end
# @return [SpecificationProvider] the provider that knows about
# dependencies, requirements, specifications, versions, etc.
attr_reader :specification_provider
# @return [UI] the UI that knows how to communicate feedback about the
# resolution process back to the user
attr_reader :resolver_ui
# @return [DependencyGraph] the base dependency graph to which
# dependencies should be 'locked'
attr_reader :base
# @return [Array] the dependencies that were explicitly required
attr_reader :original_requested
# Initializes a new resolution.
# @param [SpecificationProvider] specification_provider
# see {#specification_provider}
# @param [UI] resolver_ui see {#resolver_ui}
# @param [Array] requested see {#original_requested}
# @param [DependencyGraph] base see {#base}
def initialize(specification_provider, resolver_ui, requested, base)
@specification_provider = specification_provider
@resolver_ui = resolver_ui
@original_requested = requested
@base = base
@states = []
@iteration_counter = 0
@parents_of = Hash.new { |h, k| h[k] = [] }
end
# Resolves the {#original_requested} dependencies into a full dependency
# graph
# @raise [ResolverError] if successful resolution is impossible
# @return [DependencyGraph] the dependency graph of successfully resolved
# dependencies
def resolve
start_resolution
while state
break if !state.requirement && state.requirements.empty?
indicate_progress
if state.respond_to?(:pop_possibility_state) # DependencyState
debug(depth) { "Creating possibility state for #{requirement} (#{possibilities.count} remaining)" }
state.pop_possibility_state.tap do |s|
if s
states.push(s)
activated.tag(s)
end
end
end
process_topmost_state
end
resolve_activated_specs
ensure
end_resolution
end
# @return [Integer] the number of resolver iterations in between calls to
# {#resolver_ui}'s {UI#indicate_progress} method
attr_accessor :iteration_rate
private :iteration_rate
# @return [Time] the time at which resolution began
attr_accessor :started_at
private :started_at
# @return [Array<ResolutionState>] the stack of states for the resolution
attr_accessor :states
private :states
private
# Sets up the resolution process
# @return [void]
def start_resolution
@started_at = Time.now
push_initial_state
debug { "Starting resolution (#{@started_at})\nUser-requested dependencies: #{original_requested}" }
resolver_ui.before_resolution
end
def resolve_activated_specs
activated.vertices.each do |_, vertex|
next unless vertex.payload
latest_version = vertex.payload.possibilities.reverse_each.find do |possibility|
vertex.requirements.all? { |req| requirement_satisfied_by?(req, activated, possibility) }
end
activated.set_payload(vertex.name, latest_version)
end
activated.freeze
end
# Ends the resolution process
# @return [void]
def end_resolution
resolver_ui.after_resolution
debug do
"Finished resolution (#{@iteration_counter} steps) " \
"(Took #{(ended_at = Time.now) - @started_at} seconds) (#{ended_at})"
end
debug { 'Unactivated: ' + Hash[activated.vertices.reject { |_n, v| v.payload }].keys.join(', ') } if state
debug { 'Activated: ' + Hash[activated.vertices.select { |_n, v| v.payload }].keys.join(', ') } if state
end
require_relative 'state'
require_relative 'modules/specification_provider'
require_relative 'delegates/resolution_state'
require_relative 'delegates/specification_provider'
include Bundler::Molinillo::Delegates::ResolutionState
include Bundler::Molinillo::Delegates::SpecificationProvider
# Processes the topmost available {RequirementState} on the stack
# @return [void]
def process_topmost_state
if possibility
attempt_to_activate
else
create_conflict
unwind_for_conflict
end
rescue CircularDependencyError => underlying_error
create_conflict(underlying_error)
unwind_for_conflict
end
# @return [Object] the current possibility that the resolution is trying
# to activate
def possibility
possibilities.last
end
# @return [RequirementState] the current state the resolution is
# operating upon
def state
states.last
end
# Creates and pushes the initial state for the resolution, based upon the
# {#requested} dependencies
# @return [void]
def push_initial_state
graph = DependencyGraph.new.tap do |dg|
original_requested.each do |requested|
vertex = dg.add_vertex(name_for(requested), nil, true)
vertex.explicit_requirements << requested
end
dg.tag(:initial_state)
end
push_state_for_requirements(original_requested, true, graph)
end
# Unwinds the states stack because a conflict has been encountered
# @return [void]
def unwind_for_conflict
details_for_unwind = build_details_for_unwind
unwind_options = unused_unwind_options
debug(depth) { "Unwinding for conflict: #{requirement} to #{details_for_unwind.state_index / 2}" }
conflicts.tap do |c|
sliced_states = states.slice!((details_for_unwind.state_index + 1)..-1)
raise_error_unless_state(c)
activated.rewind_to(sliced_states.first || :initial_state) if sliced_states
state.conflicts = c
state.unused_unwind_options = unwind_options
filter_possibilities_after_unwind(details_for_unwind)
index = states.size - 1
@parents_of.each { |_, a| a.reject! { |i| i >= index } }
state.unused_unwind_options.reject! { |uw| uw.state_index >= index }
end
end
# Raises a VersionConflict error, or any underlying error, if there is no
# current state
# @return [void]
def raise_error_unless_state(conflicts)
return if state
error = conflicts.values.map(&:underlying_error).compact.first
raise error || VersionConflict.new(conflicts, specification_provider)
end
# @return [UnwindDetails] Details of the nearest index to which we could unwind
def build_details_for_unwind
# Get the possible unwinds for the current conflict
current_conflict = conflicts[name]
binding_requirements = binding_requirements_for_conflict(current_conflict)
unwind_details = unwind_options_for_requirements(binding_requirements)
last_detail_for_current_unwind = unwind_details.sort.last
current_detail = last_detail_for_current_unwind
# Look for past conflicts that could be unwound to affect the
# requirement tree for the current conflict
relevant_unused_unwinds = unused_unwind_options.select do |alternative|
intersecting_requirements =
last_detail_for_current_unwind.all_requirements &
alternative.requirements_unwound_to_instead
next if intersecting_requirements.empty?
# Find the highest index unwind whilst looping through
current_detail = alternative if alternative > current_detail
alternative
end
# Add the current unwind options to the `unused_unwind_options` array.
# The "used" option will be filtered out during `unwind_for_conflict`.
state.unused_unwind_options += unwind_details.reject { |detail| detail.state_index == -1 }
# Update the requirements_unwound_to_instead on any relevant unused unwinds
relevant_unused_unwinds.each { |d| d.requirements_unwound_to_instead << current_detail.state_requirement }
unwind_details.each { |d| d.requirements_unwound_to_instead << current_detail.state_requirement }
current_detail
end
# @param [Array<Object>] binding_requirements array of requirements that combine to create a conflict
# @return [Array<UnwindDetails>] array of UnwindDetails that have a chance
# of resolving the passed requirements
def unwind_options_for_requirements(binding_requirements)
unwind_details = []
trees = []
binding_requirements.reverse_each do |r|
partial_tree = [r]
trees << partial_tree
unwind_details << UnwindDetails.new(-1, nil, partial_tree, binding_requirements, trees, [])
# If this requirement has alternative possibilities, check if any would
# satisfy the other requirements that created this conflict
requirement_state = find_state_for(r)
if conflict_fixing_possibilities?(requirement_state, binding_requirements)
unwind_details << UnwindDetails.new(
states.index(requirement_state),
r,
partial_tree,
binding_requirements,
trees,
[]
)
end
# Next, look at the parent of this requirement, and check if the requirement
# could have been avoided if an alternative PossibilitySet had been chosen
parent_r = parent_of(r)
next if parent_r.nil?
partial_tree.unshift(parent_r)
requirement_state = find_state_for(parent_r)
if requirement_state.possibilities.any? { |set| !set.dependencies.include?(r) }
unwind_details << UnwindDetails.new(
states.index(requirement_state),
parent_r,
partial_tree,
binding_requirements,
trees,
[]
)
end
# Finally, look at the grandparent and up of this requirement, looking
# for any possibilities that wouldn't create their parent requirement
grandparent_r = parent_of(parent_r)
until grandparent_r.nil?
partial_tree.unshift(grandparent_r)
requirement_state = find_state_for(grandparent_r)
if requirement_state.possibilities.any? { |set| !set.dependencies.include?(parent_r) }
unwind_details << UnwindDetails.new(
states.index(requirement_state),
grandparent_r,
partial_tree,
binding_requirements,
trees,
[]
)
end
parent_r = grandparent_r
grandparent_r = parent_of(parent_r)
end
end
unwind_details
end
# @param [DependencyState] state
# @param [Array] binding_requirements array of requirements
# @return [Boolean] whether or not the given state has any possibilities
# that could satisfy the given requirements
def conflict_fixing_possibilities?(state, binding_requirements)
return false unless state
state.possibilities.any? do |possibility_set|
possibility_set.possibilities.any? do |poss|
possibility_satisfies_requirements?(poss, binding_requirements)
end
end
end
# Filter's a state's possibilities to remove any that would not fix the
# conflict we've just rewound from
# @param [UnwindDetails] unwind_details details of the conflict just
# unwound from
# @return [void]
def filter_possibilities_after_unwind(unwind_details)
return unless state && !state.possibilities.empty?
if unwind_details.unwinding_to_primary_requirement?
filter_possibilities_for_primary_unwind(unwind_details)
else
filter_possibilities_for_parent_unwind(unwind_details)
end
end
# Filter's a state's possibilities to remove any that would not satisfy
# the requirements in the conflict we've just rewound from
# @param [UnwindDetails] unwind_details details of the conflict just unwound from
# @return [void]
def filter_possibilities_for_primary_unwind(unwind_details)
unwinds_to_state = unused_unwind_options.select { |uw| uw.state_index == unwind_details.state_index }
unwinds_to_state << unwind_details
unwind_requirement_sets = unwinds_to_state.map(&:conflicting_requirements)
state.possibilities.reject! do |possibility_set|
possibility_set.possibilities.none? do |poss|
unwind_requirement_sets.any? do |requirements|
possibility_satisfies_requirements?(poss, requirements)
end
end
end
end
# @param [Object] possibility a single possibility
# @param [Array] requirements an array of requirements
# @return [Boolean] whether the possibility satisfies all of the
# given requirements
def possibility_satisfies_requirements?(possibility, requirements)
name = name_for(possibility)
activated.tag(:swap)
activated.set_payload(name, possibility) if activated.vertex_named(name)
satisfied = requirements.all? { |r| requirement_satisfied_by?(r, activated, possibility) }
activated.rewind_to(:swap)
satisfied
end
# 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]
def filter_possibilities_for_parent_unwind(unwind_details)
unwinds_to_state = unused_unwind_options.select { |uw| uw.state_index == unwind_details.state_index }
unwinds_to_state << unwind_details
primary_unwinds = unwinds_to_state.select(&:unwinding_to_primary_requirement?).uniq
parent_unwinds = unwinds_to_state.uniq - primary_unwinds
allowed_possibility_sets = primary_unwinds.flat_map do |unwind|
states[unwind.state_index].possibilities.select do |possibility_set|
possibility_set.possibilities.any? do |poss|
possibility_satisfies_requirements?(poss, unwind.conflicting_requirements)
end
end
end
requirements_to_avoid = parent_unwinds.flat_map(&:sub_dependencies_to_avoid)
state.possibilities.reject! do |possibility_set|
!allowed_possibility_sets.include?(possibility_set) &&
(requirements_to_avoid - possibility_set.dependencies).empty?
end
end
# @param [Conflict] conflict
# @return [Array] minimal array of requirements that would cause the passed
# conflict to occur.
def binding_requirements_for_conflict(conflict)
return [conflict.requirement] if conflict.possibility.nil?
possible_binding_requirements = conflict.requirements.values.flatten(1).uniq
# When there's a `CircularDependency` error the conflicting requirement
# (the one causing the circular) won't be `conflict.requirement`
# (which won't be for the right state, because we won't have created it,
# because it's circular).
# We need to make sure we have that requirement in the conflict's list,
# otherwise we won't be able to unwind properly, so we just return all
# the requirements for the conflict.
return possible_binding_requirements if conflict.underlying_error
possibilities = search_for(conflict.requirement)
# If all the requirements together don't filter out all possibilities,
# then the only two requirements we need to consider are the initial one
# (where the dependency's version was first chosen) and the last
if binding_requirement_in_set?(nil, possible_binding_requirements, possibilities)
return [conflict.requirement, requirement_for_existing_name(name_for(conflict.requirement))].compact
end
# Loop through the possible binding requirements, removing each one
# that doesn't bind. Use a `reverse_each` as we want the earliest set of
# binding requirements, and don't use `reject!` as we wish to refine the
# array *on each iteration*.
binding_requirements = possible_binding_requirements.dup
possible_binding_requirements.reverse_each do |req|
next if req == conflict.requirement
unless binding_requirement_in_set?(req, binding_requirements, possibilities)
binding_requirements -= [req]
end
end
binding_requirements
end
# @param [Object] requirement we wish to check
# @param [Array] possible_binding_requirements array of requirements
# @param [Array] possibilities array of possibilities the requirements will be used to filter
# @return [Boolean] whether or not the given requirement is required to filter
# out all elements of the array of possibilities.
def binding_requirement_in_set?(requirement, possible_binding_requirements, possibilities)
possibilities.any? do |poss|
possibility_satisfies_requirements?(poss, possible_binding_requirements - [requirement])
end
end
# @param [Object] requirement
# @return [Object] the requirement that led to `requirement` being added
# to the list of requirements.
def parent_of(requirement)
return unless requirement
return unless index = @parents_of[requirement].last
return unless parent_state = @states[index]
parent_state.requirement
end
# @param [String] name
# @return [Object] the requirement that led to a version of a possibility
# with the given name being activated.
def requirement_for_existing_name(name)
return nil unless vertex = activated.vertex_named(name)
return nil unless vertex.payload
states.find { |s| s.name == name }.requirement
end
# @param [Object] requirement
# @return [ResolutionState] the state whose `requirement` is the given
# `requirement`.
def find_state_for(requirement)
return nil unless requirement
states.find { |i| requirement == i.requirement }
end
# @param [Object] underlying_error
# @return [Conflict] a {Conflict} that reflects the failure to activate
# the {#possibility} in conjunction with the current {#state}
def create_conflict(underlying_error = nil)
vertex = activated.vertex_named(name)
locked_requirement = locked_requirement_named(name)
requirements = {}
unless vertex.explicit_requirements.empty?
requirements[name_for_explicit_dependency_source] = vertex.explicit_requirements
end
requirements[name_for_locking_dependency_source] = [locked_requirement] if locked_requirement
vertex.incoming_edges.each do |edge|
(requirements[edge.origin.payload.latest_version] ||= []).unshift(edge.requirement)
end
activated_by_name = {}
activated.each { |v| activated_by_name[v.name] = v.payload.latest_version if v.payload }
conflicts[name] = Conflict.new(
requirement,
requirements,
vertex.payload && vertex.payload.latest_version,
possibility,
locked_requirement,
requirement_trees,
activated_by_name,
underlying_error
)
end
# @return [Array<Array<Object>>] The different requirement
# trees that led to every requirement for the current spec.
def requirement_trees
vertex = activated.vertex_named(name)
vertex.requirements.map { |r| requirement_tree_for(r) }
end
# @param [Object] requirement
# @return [Array<Object>] the list of requirements that led to
# `requirement` being required.
def requirement_tree_for(requirement)
tree = []
while requirement
tree.unshift(requirement)
requirement = parent_of(requirement)
end
tree
end
# Indicates progress roughly once every second
# @return [void]
def indicate_progress
@iteration_counter += 1
@progress_rate ||= resolver_ui.progress_rate
if iteration_rate.nil?
if Time.now - started_at >= @progress_rate
self.iteration_rate = @iteration_counter
end
end
if iteration_rate && (@iteration_counter % iteration_rate) == 0
resolver_ui.indicate_progress
end
end
# Calls the {#resolver_ui}'s {UI#debug} method
# @param [Integer] depth the depth of the {#states} stack
# @param [Proc] block a block that yields a {#to_s}
# @return [void]
def debug(depth = 0, &block)
resolver_ui.debug(depth, &block)
end
# Attempts to activate the current {#possibility}
# @return [void]
def attempt_to_activate
debug(depth) { 'Attempting to activate ' + possibility.to_s }
existing_vertex = activated.vertex_named(name)
if existing_vertex.payload
debug(depth) { "Found existing spec (#{existing_vertex.payload})" }
attempt_to_filter_existing_spec(existing_vertex)
else
latest = possibility.latest_version
possibility.possibilities.select! do |possibility|
requirement_satisfied_by?(requirement, activated, possibility)
end
if possibility.latest_version.nil?
# ensure there's a possibility for better error messages
possibility.possibilities << latest if latest
create_conflict
unwind_for_conflict
else
activate_new_spec
end
end
end
# Attempts to update the existing vertex's `PossibilitySet` with a filtered version
# @return [void]
def attempt_to_filter_existing_spec(vertex)
filtered_set = filtered_possibility_set(vertex)
if !filtered_set.possibilities.empty?
activated.set_payload(name, filtered_set)
new_requirements = requirements.dup
push_state_for_requirements(new_requirements, false)
else
create_conflict
debug(depth) { "Unsatisfied by existing spec (#{vertex.payload})" }
unwind_for_conflict
end
end
# Generates a filtered version of the existing vertex's `PossibilitySet` using the
# current state's `requirement`
# @param [Object] vertex existing vertex
# @return [PossibilitySet] filtered possibility set
def filtered_possibility_set(vertex)
PossibilitySet.new(vertex.payload.dependencies, vertex.payload.possibilities & possibility.possibilities)
end
# @param [String] requirement_name the spec name to search for
# @return [Object] the locked spec named `requirement_name`, if one
# is found on {#base}
def locked_requirement_named(requirement_name)
vertex = base.vertex_named(requirement_name)
vertex && vertex.payload
end
# Add the current {#possibility} to the dependency graph of the current
# {#state}
# @return [void]
def activate_new_spec
conflicts.delete(name)
debug(depth) { "Activated #{name} at #{possibility}" }
activated.set_payload(name, possibility)
require_nested_dependencies_for(possibility)
end
# Requires the dependencies that the recently activated spec has
# @param [Object] possibility_set the PossibilitySet that has just been
# activated
# @return [void]
def require_nested_dependencies_for(possibility_set)
nested_dependencies = dependencies_for(possibility_set.latest_version)
debug(depth) { "Requiring nested dependencies (#{nested_dependencies.join(', ')})" }
nested_dependencies.each do |d|
activated.add_child_vertex(name_for(d), nil, [name_for(possibility_set.latest_version)], d)
parent_index = states.size - 1
parents = @parents_of[d]
parents << parent_index if parents.empty?
end
push_state_for_requirements(requirements + nested_dependencies, !nested_dependencies.empty?)
end
# Pushes a new {DependencyState} that encapsulates both existing and new
# requirements
# @param [Array] new_requirements
# @param [Boolean] requires_sort
# @param [Object] new_activated
# @return [void]
def push_state_for_requirements(new_requirements, requires_sort = true, new_activated = activated)
new_requirements = sort_dependencies(new_requirements.uniq, new_activated, conflicts) if requires_sort
new_requirement = nil
loop do
new_requirement = new_requirements.shift
break if new_requirement.nil? || states.none? { |s| s.requirement == new_requirement }
end
new_name = new_requirement ? name_for(new_requirement) : ''.freeze
possibilities = possibilities_for_requirement(new_requirement)
handle_missing_or_push_dependency_state DependencyState.new(
new_name, new_requirements, new_activated,
new_requirement, possibilities, depth, conflicts.dup, unused_unwind_options.dup
)
end
# Checks a proposed requirement with any existing locked requirement
# before generating an array of possibilities for it.
# @param [Object] requirement the proposed requirement
# @param [Object] activated
# @return [Array] possibilities
def possibilities_for_requirement(requirement, activated = self.activated)
return [] unless requirement
if locked_requirement_named(name_for(requirement))
return locked_requirement_possibility_set(requirement, activated)
end
group_possibilities(search_for(requirement))
end
# @param [Object] requirement the proposed requirement
# @param [Object] activated
# @return [Array] possibility set containing only the locked requirement, if any
def locked_requirement_possibility_set(requirement, activated = self.activated)
all_possibilities = search_for(requirement)
locked_requirement = locked_requirement_named(name_for(requirement))
# Longwinded way to build a possibilities array with either the locked
# requirement or nothing in it. Required, since the API for
# locked_requirement isn't guaranteed.
locked_possibilities = all_possibilities.select do |possibility|
requirement_satisfied_by?(locked_requirement, activated, possibility)
end
group_possibilities(locked_possibilities)
end
# Build an array of PossibilitySets, with each element representing a group of
# dependency versions that all have the same sub-dependency version constraints
# and are contiguous.
# @param [Array] possibilities an array of possibilities
# @return [Array<PossibilitySet>] an array of possibility sets
def group_possibilities(possibilities)
possibility_sets = []
current_possibility_set = nil
possibilities.reverse_each do |possibility|
dependencies = dependencies_for(possibility)
if current_possibility_set && current_possibility_set.dependencies == dependencies
current_possibility_set.possibilities.unshift(possibility)
else
possibility_sets.unshift(PossibilitySet.new(dependencies, [possibility]))
current_possibility_set = possibility_sets.first
end
end
possibility_sets
end
# 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]
def handle_missing_or_push_dependency_state(state)
if state.requirement && state.possibilities.empty? && allow_missing?(state.requirement)
state.activated.detach_vertex_named(state.name)
push_state_for_requirements(state.requirements.dup, false, state.activated)
else
states.push(state).tap { activated.tag(state) }
end
end
end
end
end