Merge pull request #723 from lsylvester/cached-environment-nils

cache nil values in the CachedEnvironment

CHANGELOG.md

@@ -13,6 +13,7 @@ Get upgrade notes from Sprockets 3.x to 4.x at https://github.com/rails/sprocket
 - Allow assets already fingerprinted to be served through `Sprockets::Server`
 - Do not fingerprint files that already contain a valid digest in their name
 - Remove remaining support for Ruby < 2.4.[#672](https://github.com/rails/sprockets/pull/672)
+- Fix `CachedEnvironment` caching nil values [#723](https://github.com/rails/sprockets/pull/723)
 
 ## 4.0.2
 

lib/sprockets/cached_environment.rb

@@ -31,27 +31,27 @@ def cached
 
     # Internal: Cache Environment#entries
     def entries(path)
-      @entries[path] ||= super(path)
+      @entries.fetch(path){ @entries[path] = super(path) }
     end
 
     # Internal: Cache Environment#stat
     def stat(path)
-      @stats[path] ||= super(path)
+      @stats.fetch(path){ @stats[path] = super(path) }
     end
 
     # Internal: Cache Environment#load
     def load(uri)
-      @uris[uri] ||= super(uri)
+      @uris.fetch(uri){ @uris[uri] = super(uri) }
     end
 
     # Internal: Cache Environment#processor_cache_key
     def processor_cache_key(str)
-      @processor_cache_keys[str] ||= super(str)
+      @processor_cache_keys.fetch(str){ @processor_cache_keys[str] = super(str) }
     end
 
     # Internal: Cache Environment#resolve_dependency
     def resolve_dependency(str)
-      @resolved_dependencies[str] ||= super(str)
+      @resolved_dependencies.fetch(str){ @resolved_dependencies[str] = super(str) }
     end
 
     private

test/test_performance.rb

@@ -2,6 +2,7 @@
 require 'sprockets_test'
 
 $file_stat_calls = nil
+$file_exist_calls = nil
 class << File
   alias_method :original_stat, :stat
   def stat(filename)
@@ -11,6 +12,15 @@ def stat(filename)
     end
     original_stat(filename)
   end
+
+  alias_method :original_exist?, :exist?
+  def exist?(filename)
+    if $file_exist_calls
+      $file_exist_calls[filename.to_s] ||= []
+      $file_exist_calls[filename.to_s] << caller
+    end
+    original_exist?(filename)
+  end
 end
 
 $dir_entires_calls = nil
@@ -56,6 +66,7 @@ def teardown
     $bundle_processor_calls = nil
     $cache_get_calls = nil
     $cache_set_calls = nil
+    $file_exist_calls = nil
   end
 
   test "simple file" do
@@ -451,6 +462,7 @@ def new_environment(path = fixture_path('default'))
 
   def reset_stats!
     $file_stat_calls = {}
+    $file_exist_calls = {}
     $dir_entires_calls = {}
     $processor_calls = {}
     $bundle_processor_calls = {}
@@ -473,9 +485,15 @@ def assert_no_redundant_stat_calls
       assert_equal 1, callers.size, "File.stat(#{path.inspect}) called #{callers.size} times\n\n#{format_callers(callers)}"
     end
 
+    $file_exist_calls.each do |path, callers|
+      assert_equal 1, callers.size, "File.exist?(#{path.inspect}) called #{callers.size} times\n\n#{format_callers(callers)}"
+    end
+
     $dir_entires_calls.each do |path, callers|
       assert_equal 1, callers.size, "Dir.entries(#{path.inspect}) called #{callers.size} times\n\n#{format_callers(callers)}"
     end
+
+
   end
 
   def assert_no_processor_calls