* lib/rubygems.rb, lib/rubygems/*, test/rubygems/*: Update rubygems-2.6.1.

  Please see entries of 2.6.0 and 2.6.1 on
  https://github.com/rubygems/rubygems/blob/master/History.txt
  [fix GH-1270] Patch by @segiddins

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53992 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 52 insertions, 20 deletions

diff --git a/lib/rubygems/resolver/installer_set.rb b/lib/rubygems/resolver/installer_set.rb
index 1ed02e6f9f..07fffeb150 100644
--- a/lib/rubygems/resolver/installer_set.rb
+++ b/lib/rubygems/resolver/installer_set.rb
@@ -138,10 +138,14 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
 
       local_source = Gem::Source::Local.new
 
-      if local_spec = local_source.find_gem(name, dep.requirement) then
-        res << Gem::Resolver::IndexSpecification.new(
-          self, local_spec.name, local_spec.version,
-          local_source, local_spec.platform)
+      begin
+        if local_spec = local_source.find_gem(name, dep.requirement) then
+          res << Gem::Resolver::IndexSpecification.new(
+            self, local_spec.name, local_spec.version,
+            local_source, local_spec.platform)
+        end
+      rescue Gem::Package::FormatError
+        # ignore
       end
     end
 
diff --git a/lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb b/lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb
index deb4659448..42563664d6 100644
--- a/lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb
+++ b/lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb
@@ -127,6 +127,10 @@ module Gem::Resolver::Molinillo
         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
diff --git a/lib/rubygems/resolver/molinillo/lib/molinillo/gem_metadata.rb b/lib/rubygems/resolver/molinillo/lib/molinillo/gem_metadata.rb
index 79cae2c697..1b66500f0f 100644
--- a/lib/rubygems/resolver/molinillo/lib/molinillo/gem_metadata.rb
+++ b/lib/rubygems/resolver/molinillo/lib/molinillo/gem_metadata.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 module Gem::Resolver::Molinillo
   # The version of Gem::Resolver::Molinillo.
-  VERSION = '0.4.1'.freeze
+  VERSION = '0.4.3'.freeze
 end
diff --git a/lib/rubygems/resolver/molinillo/lib/molinillo/modules/ui.rb b/lib/rubygems/resolver/molinillo/lib/molinillo/modules/ui.rb
index 348ace286a..540b5b809c 100644
--- a/lib/rubygems/resolver/molinillo/lib/molinillo/modules/ui.rb
+++ b/lib/rubygems/resolver/molinillo/lib/molinillo/modules/ui.rb
@@ -58,7 +58,8 @@ module Gem::Resolver::Molinillo
     #
     # @return [Boolean]
     def debug?
-      @debug_mode ||= ENV['MOLINILLO_DEBUG']
+      return @debug_mode if defined?(@debug_mode)
+      @debug_mode = ENV['MOLINILLO_DEBUG']
     end
   end
 end
diff --git a/lib/rubygems/resolver/molinillo/lib/molinillo/resolution.rb b/lib/rubygems/resolver/molinillo/lib/molinillo/resolution.rb
index 0f822f0b82..2fc18843fe 100644
--- a/lib/rubygems/resolver/molinillo/lib/molinillo/resolution.rb
+++ b/lib/rubygems/resolver/molinillo/lib/molinillo/resolution.rb
@@ -342,26 +342,37 @@ module Gem::Resolver::Molinillo
       # @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)
+            requirements.delete_if { |r| name_for(r) == 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
@@ -369,6 +380,18 @@ module Gem::Resolver::Molinillo
         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}
@@ -394,7 +417,7 @@ module Gem::Resolver::Molinillo
       # @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)