[rubygems/rubygems] Fix gem list regression when a regular gem shadows a default one

Previously, if you have bundler installed both as a regular gem and a
default gem, the default gem would be displayed by `gem list`.

https://github.com/rubygems/rubygems/commit/10a6b1736e

lib/rubygems/query_utils.rb

@@ -132,7 +132,7 @@ module Gem::QueryUtils
       version_matches = show_prereleases? || !s.version.prerelease?
 
       name_matches && version_matches
-    end
+    end.uniq(&:full_name)
 
     spec_tuples = specs.map do |spec|
       [spec.name_tuple, spec]

test/rubygems/test_gem_commands_list_command.rb

@@ -8,7 +8,9 @@ class TestGemCommandsListCommand < Gem::TestCase
     super
 
     @cmd = Gem::Commands::ListCommand.new
+  end
 
+  def test_execute_installed
     spec_fetcher do |fetcher|
       fetcher.spec "c", 1
     end
@@ -16,9 +18,7 @@ class TestGemCommandsListCommand < Gem::TestCase
     @fetcher.data["#{@gem_repo}Marshal.#{Gem.marshal_version}"] = proc do
       raise Gem::RemoteFetcher::FetchError
     end
-  end
 
-  def test_execute_installed
     @cmd.handle_options %w[c --installed]
 
     assert_raise Gem::MockGemUi::SystemExitException do
@@ -30,4 +30,29 @@ class TestGemCommandsListCommand < Gem::TestCase
     assert_equal "true\n", @ui.output
     assert_equal "", @ui.error
   end
+
+  def test_execute_normal_gem_shadowing_default_gem
+    c1_default = new_default_spec "c", 1
+    install_default_gems c1_default
+
+    c1 = util_spec("c", 1) {|s| s.date = "2024-01-01" }
+    install_gem c1
+
+    Gem::Specification.reset
+
+    @cmd.handle_options %w[c]
+
+    use_ui @ui do
+      @cmd.execute
+    end
+
+    expected = <<-EOF
+
+*** LOCAL GEMS ***
+
+c (1)
+EOF
+
+    assert_equal expected, @ui.output
+  end
 end