1 files changed, 90 insertions, 4 deletions

diff --git a/lib/rubygems/resolver/installer_set.rb b/lib/rubygems/resolver/installer_set.rb
index 045c893fdc..f53b496dc7 100644
--- a/lib/rubygems/resolver/installer_set.rb
+++ b/lib/rubygems/resolver/installer_set.rb
@@ -21,6 +21,11 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
   attr_accessor :ignore_installed # :nodoc:
 
   ##
+  # The remote_set looks up remote gems for installation.
+
+  attr_reader :remote_set # :nodoc:
+
+  ##
   # Creates a new InstallerSet that will look for gems in +domain+.
 
   def initialize domain
@@ -34,11 +39,53 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
     @always_install      = []
     @ignore_dependencies = false
     @ignore_installed    = false
+    @local               = {}
     @remote_set          = Gem::Resolver::BestSet.new
     @specs               = {}
   end
 
   ##
+  # Looks up the latest specification for +dependency+ and adds it to the
+  # always_install list.
+
+  def add_always_install dependency
+    request = Gem::Resolver::DependencyRequest.new dependency, nil
+
+    found = find_all request
+
+    found.delete_if { |s|
+      s.version.prerelease? and not s.local?
+    } unless dependency.prerelease?
+
+    found = found.select do |s|
+      Gem::Source::SpecificFile === s.source or
+        Gem::Platform::RUBY == s.platform or
+        Gem::Platform.local === s.platform
+    end
+
+    if found.empty? then
+      exc = Gem::UnsatisfiableDependencyError.new request
+      exc.errors = errors
+
+      raise exc
+    end
+
+    newest = found.max_by do |s|
+      [s.version, s.platform == Gem::Platform::RUBY ? -1 : 1]
+    end
+
+    @always_install << newest.spec
+  end
+
+  ##
+  # Adds a local gem requested using +dep_name+ with the given +spec+ that can
+  # be loaded and installed using the +source+.
+
+  def add_local dep_name, spec, source
+    @local[dep_name] = [spec, source]
+  end
+
+  ##
   # Should local gems should be considered?
 
   def consider_local? # :nodoc:
@@ -53,6 +100,13 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
   end
 
   ##
+  # Errors encountered while resolving gems
+
+  def errors
+    @errors + @remote_set.errors
+  end
+
+  ##
   # Returns an array of IndexSpecification objects matching DependencyRequest
   # +req+.
 
@@ -62,30 +116,53 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
     dep  = req.dependency
 
     return res if @ignore_dependencies and
-              @always_install.none? { |spec| dep.matches_spec? spec }
+              @always_install.none? { |spec| dep.match? spec }
 
     name = dep.name
 
     dep.matching_specs.each do |gemspec|
-      next if @always_install.include? gemspec
+      next if @always_install.any? { |spec| spec.name == gemspec.name }
 
       res << Gem::Resolver::InstalledSpecification.new(self, gemspec)
     end unless @ignore_installed
 
     if consider_local? then
+      matching_local = @local.values.select do |spec, _|
+        req.match? spec
+      end.map do |spec, source|
+        Gem::Resolver::LocalSpecification.new self, spec, source
+      end
+
+      res.concat matching_local
+
       local_source = Gem::Source::Local.new
 
-      if spec = local_source.find_gem(name, dep.requirement) then
+      if local_spec = local_source.find_gem(name, dep.requirement) then
         res << Gem::Resolver::IndexSpecification.new(
-          self, spec.name, spec.version, local_source, spec.platform)
+          self, local_spec.name, local_spec.version,
+          local_source, local_spec.platform)
       end
     end
 
+    res.delete_if do |spec|
+      spec.version.prerelease? and not dep.prerelease?
+    end
+
     res.concat @remote_set.find_all req if consider_remote?
 
     res
   end
 
+  def prefetch(reqs)
+    @remote_set.prefetch(reqs)
+  end
+
+  def prerelease= allow_prerelease
+    super
+
+    @remote_set.prerelease = allow_prerelease
+  end
+
   def inspect # :nodoc:
     always_install = @always_install.map { |s| s.full_name }
 
@@ -108,6 +185,15 @@ class Gem::Resolver::InstallerSet < Gem::Resolver::Set
     end
   end
 
+  ##
+  # Has a local gem for +dep_name+ been added to this set?
+
+  def local? dep_name # :nodoc:
+    spec, = @local[dep_name]
+
+    spec
+  end
+
   def pretty_print q # :nodoc:
     q.group 2, '[InstallerSet', ']' do
       q.breakable