1 files changed, 160 insertions, 0 deletions
diff --git a/jni/ruby/lib/rubygems/resolver/conflict.rb b/jni/ruby/lib/rubygems/resolver/conflict.rb
new file mode 100644
index 0000000..902c286
--- /dev/null
+++ b/jni/ruby/lib/rubygems/resolver/conflict.rb
@@ -0,0 +1,160 @@
+##
+# Used internally to indicate that a dependency conflicted
+# with a spec that would be activated.
+
+class Gem::Resolver::Conflict
+
+  ##
+  # The specification that was activated prior to the conflict
+
+  attr_reader :activated
+
+  ##
+  # The dependency that is in conflict with the activated gem.
+
+  attr_reader :dependency
+
+  attr_reader :failed_dep # :nodoc:
+
+  ##
+  # Creates a new resolver conflict when +dependency+ is in conflict with an
+  # already +activated+ specification.
+
+  def initialize(dependency, activated, failed_dep=dependency)
+    @dependency = dependency
+    @activated = activated
+    @failed_dep = failed_dep
+  end
+
+  def == other # :nodoc:
+    self.class === other and
+      @dependency == other.dependency and
+      @activated  == other.activated  and
+      @failed_dep == other.failed_dep
+  end
+
+  ##
+  # A string explanation of the conflict.
+
+  def explain
+    "<Conflict wanted: #{@failed_dep}, had: #{activated.spec.full_name}>"
+  end
+
+  ##
+  # Return the 2 dependency objects that conflicted
+
+  def conflicting_dependencies
+    [@failed_dep.dependency, @activated.request.dependency]
+  end
+
+  ##
+  # Explanation of the conflict used by exceptions to print useful messages
+
+  def explanation
+    activated   = @activated.spec.full_name
+    dependency  = @failed_dep.dependency
+    requirement = dependency.requirement
+    alternates  = dependency.matching_specs.map { |spec| spec.full_name }
+
+    unless alternates.empty? then
+      matching = <<-MATCHING.chomp
+
+  Gems matching %s:
+    %s
+      MATCHING
+
+      matching = matching % [
+        dependency,
+        alternates.join(', '),
+      ]
+    end
+
+    explanation = <<-EXPLANATION
+  Activated %s
+  which does not match conflicting dependency (%s)
+
+  Conflicting dependency chains:
+    %s
+
+  versus:
+    %s
+%s
+    EXPLANATION
+
+    explanation % [
+      activated, requirement,
+      request_path(@activated).reverse.join(", depends on\n    "),
+      request_path(@failed_dep).reverse.join(", depends on\n    "),
+      matching,
+    ]
+  end
+
+  ##
+  # Returns true if the conflicting dependency's name matches +spec+.
+
+  def for_spec?(spec)
+    @dependency.name == spec.name
+  end
+
+  def pretty_print q # :nodoc:
+    q.group 2, '[Dependency conflict: ', ']' do
+      q.breakable
+
+      q.text 'activated '
+      q.pp @activated
+
+      q.breakable
+      q.text ' dependency '
+      q.pp @dependency
+
+      q.breakable
+      if @dependency == @failed_dep then
+        q.text ' failed'
+      else
+        q.text ' failed dependency '
+        q.pp @failed_dep
+      end
+    end
+  end
+
+  ##
+  # Path of activations from the +current+ list.
+
+  def request_path current
+    path = []
+
+    while current do
+      case current
+      when Gem::Resolver::ActivationRequest then
+        path <<
+          "#{current.request.dependency}, #{current.spec.version} activated"
+
+        current = current.parent
+      when Gem::Resolver::DependencyRequest then
+        path << "#{current.dependency}"
+
+        current = current.requester
+      else
+        raise Gem::Exception, "[BUG] unknown request class #{current.class}"
+      end
+    end
+
+    path = ['user request (gem command or Gemfile)'] if path.empty?
+
+    path
+  end
+
+  ##
+  # Return the Specification that listed the dependency
+
+  def requester
+    @failed_dep.requester
+  end
+
+end
+
+##
+# TODO: Remove in RubyGems 3
+
+Gem::Resolver::DependencyConflict = Gem::Resolver::Conflict # :nodoc:
+