Merge rubygems/rubygems HEAD

  Pick from https://github.com/rubygems/rubygems/commit/880dd95996c93adc1e032399816931b243c5fe17

1 files changed, 16 insertions, 2 deletions

diff --git a/lib/bundler/resolver.rb b/lib/bundler/resolver.rb
index c8cc88a3ee..2ad35bc931 100644
--- a/lib/bundler/resolver.rb
+++ b/lib/bundler/resolver.rb
@@ -160,7 +160,7 @@ module Bundler
       constraint_string = constraint.constraint_string
       requirements = constraint_string.split(" OR ").map {|req| Gem::Requirement.new(req.split(",")) }
 
-      if name == "bundler"
+      if name == "bundler" && bundler_pinned_to_current_version?
         custom_explanation = "the current Bundler version (#{Bundler::VERSION}) does not satisfy #{constraint}"
         extended_explanation = bundler_not_found_message(requirements)
       else
@@ -230,6 +230,12 @@ module Bundler
     def all_versions_for(package)
       name = package.name
       results = (@base[name] + filter_prereleases(@all_specs[name], package)).uniq {|spec| [spec.version.hash, spec.platform] }
+
+      if name == "bundler" && !bundler_pinned_to_current_version?
+        bundler_spec = Gem.loaded_specs["bundler"]
+        results << bundler_spec if bundler_spec
+      end
+
       locked_requirement = base_requirements[name]
       results = filter_matching_specs(results, locked_requirement) if locked_requirement
 
@@ -254,6 +260,14 @@ module Bundler
       @source_requirements[name] || @source_requirements[:default]
     end
 
+    def default_bundler_source
+      @source_requirements[:default_bundler]
+    end
+
+    def bundler_pinned_to_current_version?
+      !default_bundler_source.nil?
+    end
+
     def name_for_explicit_dependency_source
       Bundler.default_gemfile.basename.to_s
     rescue StandardError
@@ -398,7 +412,7 @@ module Bundler
     end
 
     def bundler_not_found_message(conflict_dependencies)
-      candidate_specs = filter_matching_specs(source_for(:default_bundler).specs.search("bundler"), conflict_dependencies)
+      candidate_specs = filter_matching_specs(default_bundler_source.specs.search("bundler"), conflict_dependencies)
 
       if candidate_specs.any?
         target_version = candidate_specs.last.version