1 files changed, 75 insertions, 0 deletions
diff --git a/lib/bundler/vendor/molinillo/lib/molinillo/errors.rb b/lib/bundler/vendor/molinillo/lib/molinillo/errors.rb
new file mode 100644
index 0000000000..f904bd0814
--- /dev/null
+++ b/lib/bundler/vendor/molinillo/lib/molinillo/errors.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+module Bundler::Molinillo
+  # An error that occurred during the resolution process
+  class ResolverError < StandardError; end
+
+  # An error caused by searching for a dependency that is completely unknown,
+  # i.e. has no versions available whatsoever.
+  class NoSuchDependencyError < ResolverError
+    # @return [Object] the dependency that could not be found
+    attr_accessor :dependency
+
+    # @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 = [])
+      @dependency = dependency
+      @required_by = 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}`"
+      message += " depended upon by #{sources}" unless sources.empty?
+      message
+    end
+  end
+
+  # An error caused by attempting to fulfil a dependency that was circular
+  #
+  # @note This exception will be thrown iff a {Vertex} is added to a
+  #   {DependencyGraph} that has a {DependencyGraph::Vertex#path_to?} an
+  #   existing {DependencyGraph::Vertex}
+  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)
+      super "There is a circular dependency between #{nodes.map(&:name).join(' and ')}"
+      @dependencies = nodes.map(&:payload).to_set
+    end
+  end
+
+  # An error caused by conflicts in version
+  class VersionConflict < ResolverError
+    # @return [{String => Resolution::Conflict}] the conflicts that caused
+    #   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 = []
+      conflicts.values.flatten.map(&:requirements).flatten.each do |conflicting|
+        conflicting.each do |source, conflict_requirements|
+          conflict_requirements.each do |c|
+            pairs << [c, source]
+          end
+        end
+      end
+
+      super "Unable to satisfy the following requirements:\n\n" \
+        "#{pairs.map { |r, d| "- `#{r}` required by `#{d}`" }.join("\n")}"
+      @conflicts = conflicts
+    end
+  end
+end