1 files changed, 55 insertions, 0 deletions
diff --git a/lib/rubygems/resolver/set.rb b/lib/rubygems/resolver/set.rb
new file mode 100644
index 0000000000..243fee5fd5
--- /dev/null
+++ b/lib/rubygems/resolver/set.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+##
+# Resolver sets are used to look up specifications (and their
+# dependencies) used in resolution.  This set is abstract.
+
+class Gem::Resolver::Set
+  ##
+  # Set to true to disable network access for this set
+
+  attr_accessor :remote
+
+  ##
+  # Errors encountered when resolving gems
+
+  attr_accessor :errors
+
+  ##
+  # When true, allows matching of requests to prerelease gems.
+
+  attr_accessor :prerelease
+
+  def initialize # :nodoc:
+    @prerelease = false
+    @remote     = true
+    @errors     = []
+  end
+
+  ##
+  # The find_all method must be implemented.  It returns all Resolver
+  # Specification objects matching the given DependencyRequest +req+.
+
+  def find_all(req)
+    raise NotImplementedError
+  end
+
+  ##
+  # The #prefetch method may be overridden, but this is not necessary.  This
+  # default implementation does nothing, which is suitable for sets where
+  # looking up a specification is cheap (such as installed gems).
+  #
+  # When overridden, the #prefetch method should look up specifications
+  # matching +reqs+.
+
+  def prefetch(reqs)
+  end
+
+  ##
+  # When true, this set is allowed to access the network when looking up
+  # specifications or dependencies.
+
+  def remote? # :nodoc:
+    @remote
+  end
+end