Auto merge of #4253 - bundler:seg-molinillo-0.4.2, r=segiddins

[Resolver] Update Molinillo to 0.4.2

Closes #4198.
Closes #4101.

lib/bundler/vendor/molinillo/lib/molinillo.rb

@@ -3,3 +3,7 @@
 require 'bundler/vendor/molinillo/lib/molinillo/resolver'
 require 'bundler/vendor/molinillo/lib/molinillo/modules/ui'
 require 'bundler/vendor/molinillo/lib/molinillo/modules/specification_provider'
+
+# Bundler::Molinillo is a generic dependency resolution algorithm.
+module Bundler::Molinillo
+end

lib/bundler/vendor/molinillo/lib/molinillo/dependency_graph.rb

@@ -14,8 +14,10 @@ def each
 
     include TSort
 
+    # @visibility private
     alias_method :tsort_each_node, :each
 
+    # @visibility private
     def tsort_each_child(vertex, &block)
       vertex.successors.each(&block)
     end
@@ -41,12 +43,14 @@ def self.tsort(vertices)
     #   by {Vertex#name}
     attr_reader :vertices
 
+    # Initializes an empty dependency graph
     def initialize
       @vertices = {}
     end
 
     # Initializes a copy of a {DependencyGraph}, ensuring that all {#vertices}
     # are properly copied.
+    # @param [DependencyGraph] other the graph to copy.
     def initialize_copy(other)
       super
       @vertices = {}
@@ -100,6 +104,7 @@ def add_child_vertex(name, payload, parent_names, requirement)
       vertex
     end
 
+    # Adds a vertex with the given name, or updates the existing one.
     # @param [String] name
     # @param [Object] payload
     # @return [Vertex] the vertex that was added to `self`
@@ -121,6 +126,10 @@ def detach_vertex_named(name)
         v.incoming_edges.delete(e)
         detach_vertex_named(v.name) unless v.root? || v.predecessors.any?
       end
+      vertex.incoming_edges.each do |e|
+        v = e.origin
+        v.outgoing_edges.delete(e)
+      end
     end
 
     # @param [String] name
@@ -150,6 +159,8 @@ def add_edge(origin, destination, requirement)
 
     private
 
+    # Adds a new {Edge} to the dependency graph without checking for
+    # circularity.
     def add_edge_no_circular(origin, destination, requirement)
       edge = Edge.new(origin, destination, requirement)
       origin.outgoing_edges << edge
@@ -174,6 +185,7 @@ class Vertex
       attr_accessor :root
       alias_method :root?, :root
 
+      # Initializes a vertex with the given name and payload.
       # @param [String] name see {#name}
       # @param [Object] payload see {#payload}
       def initialize(name, payload)
@@ -240,6 +252,7 @@ def ==(other)
           successors.to_set == other.successors.to_set
       end
 
+      # @param  [Vertex] other the other vertex to compare to
       # @return [Boolean] whether the two vertices are equal, determined
       #   solely by {#name} and {#payload} equality
       def shallow_eql?(other)

lib/bundler/vendor/molinillo/lib/molinillo/errors.rb

@@ -11,6 +11,7 @@ class NoSuchDependencyError < ResolverError
     # @return [Array<Object>] the specifications that depended upon {#dependency}
     attr_accessor :required_by
 
+    # Initializes a new error with the given missing dependency.
     # @param [Object] dependency @see {#dependency}
     # @param [Array<Object>] required_by @see {#required_by}
     def initialize(dependency, required_by = [])
@@ -19,6 +20,8 @@ def initialize(dependency, required_by = [])
       super()
     end
 
+    # The error message for the missing dependency, including the specifications
+    # that had this dependency.
     def message
       sources = required_by.map { |r| "`#{r}`" }.join(' and ')
       message = "Unable to find a specification for `#{dependency}`"
@@ -36,6 +39,7 @@ class CircularDependencyError < ResolverError
     # [Set<Object>] the dependencies responsible for causing the error
     attr_reader :dependencies
 
+    # Initializes a new error with the given circular vertices.
     # @param [Array<DependencyGraph::Vertex>] nodes the nodes in the dependency
     #   that caused the error
     def initialize(nodes)
@@ -50,6 +54,7 @@ class VersionConflict < ResolverError
     #   resolution to fail
     attr_reader :conflicts
 
+    # Initializes a new error with the given version conflicts.
     # @param [{String => Resolution::Conflict}] conflicts see {#conflicts}
     def initialize(conflicts)
       pairs = []

lib/bundler/vendor/molinillo/lib/molinillo/gem_metadata.rb

@@ -1,3 +1,4 @@
 module Bundler::Molinillo
-  VERSION = '0.4.0'
+  # The version of Bundler::Molinillo.
+  VERSION = '0.4.2'.freeze
 end

lib/bundler/vendor/molinillo/lib/molinillo/modules/ui.rb

@@ -57,7 +57,8 @@ def debug(depth = 0)
     #
     # @return [Boolean]
     def debug?
-      @debug_mode ||= ENV['MOLINILLO_DEBUG']
+      return @debug_mode if defined?(@debug_mode)
+      @debug_mode = ENV['MOLINILLO_DEBUG']
     end
   end
 end

lib/bundler/vendor/molinillo/lib/molinillo/resolution.rb

@@ -38,6 +38,7 @@ class Resolution
       # @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}
@@ -340,33 +341,55 @@ def attempt_to_activate_existing_spec(existing_node)
       # @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.
+        vertex = swapped.vertex_named(name)
+        vertex.payload = possibility
+        return unless vertex.requirements.
             all? { |r| requirement_satisfied_by?(r, swapped, possibility) }
-        attempt_to_activate_new_spec
+        return unless new_spec_satisfied?
+        actual_vertex = activated.vertex_named(name)
+        actual_vertex.payload = possibility
+        fixup_swapped_children(actual_vertex)
+        activate_spec
+      end
+
+      # Ensures there are no orphaned successors to the given {vertex}.
+      # @param [DependencyGraph::Vertex] vertex the vertex to fix up.
+      # @return [void]
+      def fixup_swapped_children(vertex)
+        payload = vertex.payload
+        dep_names = dependencies_for(payload).map(&method(:name_for))
+        vertex.successors.each do |succ|
+          if !dep_names.include?(succ.name) && !succ.root? && succ.predecessors.to_a == [vertex]
+            debug(depth) { "Removing orphaned spec #{succ.name} after swapping #{name}" }
+            activated.detach_vertex_named(succ.name)
+          end
+        end
       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
+        if new_spec_satisfied?
           activate_spec
         else
           create_conflict
           unwind_for_conflict
         end
       end
 
+      # @return [Boolean] whether the current spec is satisfied as a new
+      # possibility.
+      def new_spec_satisfied?
+        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
+
       # @param [String] requirement_name the spec name to search for
       # @return [Object] the locked spec named `requirement_name`, if one
       #   is found on {#base}
@@ -392,7 +415,7 @@ def activate_spec
       # @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(', ')})" }
+        debug(depth) { "Requiring nested dependencies (#{nested_dependencies.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, nested_dependencies.size > 0)

lib/bundler/vendor/molinillo/lib/molinillo/resolver.rb

@@ -3,7 +3,7 @@
 module Bundler::Molinillo
   # This class encapsulates a dependency resolver.
   # The resolver is responsible for determining which set of dependencies to
-  # activate, with feedback from the the {#specification_provider}
+  # activate, with feedback from the {#specification_provider}
   #
   #
   class Resolver
@@ -17,6 +17,7 @@ class Resolver
     #   during the resolution process
     attr_reader :resolver_ui
 
+    # Initializes a new resolver.
     # @param  [SpecificationProvider] specification_provider
     #   see {#specification_provider}
     # @param  [UI] resolver_ui

lib/bundler/vendor/molinillo/lib/molinillo/state.rb

@@ -1,12 +1,12 @@
 module Bundler::Molinillo
   # A state that a {Resolution} can be in
-  # @attr [String] name
-  # @attr [Array<Object>] requirements
-  # @attr [DependencyGraph] activated
-  # @attr [Object] requirement
-  # @attr [Object] possibility
-  # @attr [Integer] depth
-  # @attr [Set<Object>] conflicts
+  # @attr [String] name the name of the current requirement
+  # @attr [Array<Object>] requirements currently unsatisfied requirements
+  # @attr [DependencyGraph] activated the graph of activated dependencies
+  # @attr [Object] requirement the current requirement
+  # @attr [Object] possibilities the possibilities to satisfy the current requirement
+  # @attr [Integer] depth the depth of the resolution
+  # @attr [Set<Object>] conflicts unresolved conflicts
   ResolutionState = Struct.new(
     :name,
     :requirements,