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 the spec 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.
Conflict = Struct.new(
:requirement,
:requirements,
:existing,
:possibility,
:locked_requirement,
:requirement_trees
)
# @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
# @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
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 unless state.requirements.any? || state.requirement
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 { |s| states.push(s) if s }
end
process_topmost_state
end
activated.freeze
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
states.push(initial_state)
debug { "Starting resolution (#{@started_at})" }
resolver_ui.before_resolution
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 'bundler/vendor/molinillo/lib/molinillo/state'
require 'bundler/vendor/molinillo/lib/molinillo/modules/specification_provider'
ResolutionState.new.members.each do |member|
define_method member do |*args, &block|
state.send(member, *args, &block)
end
end
SpecificationProvider.instance_methods(false).each do |instance_method|
define_method instance_method do |*args, &block|
begin
specification_provider.send(instance_method, *args, &block)
rescue NoSuchDependencyError => error
if state
vertex = activated.vertex_named(name_for error.dependency)
error.required_by += vertex.incoming_edges.map { |e| e.origin.name }
error.required_by << name_for_explicit_dependency_source unless vertex.explicit_requirements.empty?
end
raise
end
end
end
# Processes the topmost available {RequirementState} on the stack
# @return [void]
def process_topmost_state
if possibility
attempt_to_activate
else
create_conflict if state.is_a? PossibilityState
unwind_for_conflict until possibility && state.is_a?(DependencyState)
end
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 the initial state for the resolution, based upon the
# {#requested} dependencies
# @return [DependencyState] the initial state for the resolution
def initial_state
graph = DependencyGraph.new.tap do |dg|
original_requested.each { |r| dg.add_root_vertex(name_for(r), nil).tap { |v| v.explicit_requirements << r } }
end
requirements = sort_dependencies(original_requested, graph, {})
initial_requirement = requirements.shift
DependencyState.new(
initial_requirement && name_for(initial_requirement),
requirements,
graph,
initial_requirement,
initial_requirement && search_for(initial_requirement),
0,
{}
)
end
# Unwinds the states stack because a conflict has been encountered
# @return [void]
def unwind_for_conflict
debug(depth) { "Unwinding for conflict: #{requirement}" }
conflicts.tap do |c|
states.slice!((state_index_for_unwind + 1)..-1)
raise VersionConflict.new(c) unless state
state.conflicts = c
end
end
# @return [Integer] The index to which the resolution should unwind in the
# case of conflict.
def state_index_for_unwind
current_requirement = requirement
existing_requirement = requirement_for_existing_name(name)
until current_requirement.nil?
current_state = find_state_for(current_requirement)
return states.index(current_state) if state_any?(current_state)
current_requirement = parent_of(current_requirement)
end
until existing_requirement.nil?
existing_state = find_state_for(existing_requirement)
return states.index(existing_state) if state_any?(existing_state)
existing_requirement = parent_of(existing_requirement)
end
-1
end
# @return [Object] the requirement that led to `requirement` being added
# to the list of requirements.
def parent_of(requirement)
return nil unless requirement
seen = false
state = states.reverse_each.find do |s|
seen ||= s.requirement == requirement
seen && s.requirement != requirement && !s.requirements.include?(requirement)
end
state && state.requirement
end
# @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 activated.vertex_named(name).payload
states.reverse_each.find { |s| !s.activated.vertex_named(name).payload }.requirement
end
# @return [ResolutionState] the state whose `requirement` is the given
# `requirement`.
def find_state_for(requirement)
return nil unless requirement
states.reverse_each.find { |i| requirement == i.requirement && i.is_a?(DependencyState) }
end
# @return [Boolean] whether or not the given state has any possibilities
# left.
def state_any?(state)
state && state.possibilities.any?
end
# @return [Conflict] a {Conflict} that reflects the failure to activate
# the {#possibility} in conjunction with the current {#state}
def create_conflict
vertex = activated.vertex_named(name)
requirements = {
name_for_explicit_dependency_source => vertex.explicit_requirements,
name_for_locking_dependency_source => Array(locked_requirement_named(name)),
}
vertex.incoming_edges.each { |edge| (requirements[edge.origin.payload] ||= []).unshift(*edge.requirements) }
conflicts[name] = Conflict.new(
requirement,
Hash[requirements.select { |_, r| !r.empty? }],
vertex.payload,
possibility,
locked_requirement_named(name),
requirement_trees
)
end
# @return [Array<Array<Object>>] The different requirement
# trees that led to every requirement for the current spec.
def requirement_trees
activated.vertex_named(name).requirements.map { |r| requirement_tree_for(r) }
end
# @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_node = activated.vertex_named(name)
if existing_node.payload
debug(depth) { "Found existing spec (#{existing_node.payload})" }
attempt_to_activate_existing_spec(existing_node)
else
attempt_to_activate_new_spec
end
end
# Attempts to activate the current {#possibility} (given that it has
# already been activated)
# @return [void]
def attempt_to_activate_existing_spec(existing_node)
existing_spec = existing_node.payload
if requirement_satisfied_by?(requirement, activated, existing_spec)
new_requirements = requirements.dup
push_state_for_requirements(new_requirements)
else
return if attempt_to_swap_possibility
create_conflict
debug(depth) { "Unsatisfied by existing spec (#{existing_node.payload})" }
unwind_for_conflict
end
end
# Attempts to swp the current {#possibility} with the already-activated
# spec with the given name
# @return [Boolean] Whether the possibility was swapped into {#activated}
def attempt_to_swap_possibility
swapped = activated.dup
swapped.vertex_named(name).payload = possibility
return unless swapped.vertex_named(name).requirements.
all? { |r| requirement_satisfied_by?(r, swapped, possibility) }
attempt_to_activate_new_spec
end
# Attempts to activate the current {#possibility} (given that it hasn't
# already been activated)
# @return [void]
def attempt_to_activate_new_spec
satisfied = begin
locked_requirement = locked_requirement_named(name)
requested_spec_satisfied = requirement_satisfied_by?(requirement, activated, possibility)
locked_spec_satisfied = !locked_requirement ||
requirement_satisfied_by?(locked_requirement, activated, possibility)
debug(depth) { 'Unsatisfied by requested spec' } unless requested_spec_satisfied
debug(depth) { 'Unsatisfied by locked spec' } unless locked_spec_satisfied
requested_spec_satisfied && locked_spec_satisfied
end
if satisfied
activate_spec
else
create_conflict
unwind_for_conflict
end
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_spec
conflicts.delete(name)
debug(depth) { 'Activated ' + name + ' at ' + possibility.to_s }
vertex = activated.vertex_named(name)
vertex.payload = possibility
require_nested_dependencies_for(possibility)
end
# Requires the dependencies that the recently activated spec has
# @param [Object] activated_spec the specification that has just been
# activated
# @return [void]
def require_nested_dependencies_for(activated_spec)
nested_dependencies = dependencies_for(activated_spec)
debug(depth) { "Requiring nested dependencies (#{nested_dependencies.map(&:to_s).join(', ')})" }
nested_dependencies.each { |d| activated.add_child_vertex name_for(d), nil, [name_for(activated_spec)], d }
push_state_for_requirements(requirements + nested_dependencies)
end
# Pushes a new {DependencyState} that encapsulates both existing and new
# requirements
# @param [Array] new_requirements
# @return [void]
def push_state_for_requirements(new_requirements)
new_requirements = sort_dependencies(new_requirements.uniq, activated, conflicts)
new_requirement = new_requirements.shift
states.push DependencyState.new(
new_requirement ? name_for(new_requirement) : '',
new_requirements,
activated.dup,
new_requirement,
new_requirement ? search_for(new_requirement) : [],
depth,
conflicts.dup
)
end
end
end
end