use ruby 2.7's filter_map instead of select + map

Related: c3d7794, bbbc861

Author: skipkayhil

.rubocop.yml

@@ -259,6 +259,9 @@ Performance/FlatMap:
 Performance/MapCompact:
   Enabled: true
 
+Performance/SelectMap:
+  Enabled: true
+
 Performance/RedundantMerge:
   Enabled: true
 

actionview/lib/action_view/testing/resolvers.rb

@@ -24,10 +24,8 @@ def to_s
 
     private
       def template_glob(glob)
-        @hash.keys.select do |path|
-          File.fnmatch(glob, path)
-        end.map do |fixture|
-          "/#{fixture}"
+        @hash.keys.filter_map do |path|
+          "/#{path}" if File.fnmatch(glob, path)
         end
       end
 

guides/rails_guides/kindle.rb

@@ -17,7 +17,7 @@ def generate(output_dir, mobi_outfile, logfile)
       puts "=> Arranging html pages in document order"
       toc = File.read("toc.ncx")
       doc = Nokogiri::XML(toc).xpath("//ncx:content", "ncx" => "http://www.daisy.org/z3986/2005/ncx/")
-      html_pages = doc.select { |c| c[:src] }.map { |c| c[:src] }.uniq
+      html_pages = doc.filter_map { |c| c[:src] }.uniq
 
       generate_front_matter(html_pages)
 

railties/lib/rails/info_controller.rb

@@ -34,9 +34,7 @@ def routes
 
   private
     def match_route
-      _routes.routes.select { |route|
-        yield route.path
-      }.map { |route| route.path.spec.to_s }
+      _routes.routes.filter_map { |route| route.path.spec.to_s if yield route.path }
     end
 
     def with_leading_slash(path)

railties/lib/rails/test_unit/runner.rb

@@ -63,7 +63,9 @@ def compose_filter(runnable, filter)
         private
           def extract_filters(argv)
             # Extract absolute and relative paths but skip -n /.*/ regexp filters.
-            argv.select { |arg| path_argument?(arg) && !regexp_filter?(arg) }.map do |path|
+            argv.filter_map do |path|
+              next unless path_argument?(path) && !regexp_filter?(path)
+
               path = path.tr("\\", "/")
               case
               when /(:\d+)+$/.match?(path)