Merge pull request #15616 from apanzerj/fix_long_key_paths

fix error with long keys in ActiveSupport::Cache::FileStore

activesupport/CHANGELOG.md

+*   Fixed `ActiveSupport::Cache::FileStore` exploding with long paths.
+    *Adam Panzer / Michael Grosser* 
+
 *   Fixed `ActiveSupport::TimeWithZone#-` so precision is not unnecessarily lost
     when working with objects with a nanosecond component.
 

activesupport/lib/active_support/cache/file_store.rb

@@ -14,6 +14,7 @@ class FileStore < Store
 
       DIR_FORMATTER = "%03X"
       FILENAME_MAX_SIZE = 228 # max filename size on file system is 255, minus room for timestamp and random characters appended by Tempfile (used by atomic write)
+      FILEPATH_MAX_SIZE = 900 # max is 1024, plus some room
       EXCLUDED_DIRS = ['.', '..'].freeze
 
       def initialize(cache_path, options = nil)
@@ -117,6 +118,10 @@ def lock_file(file_name, &block) # :nodoc:
 
         # Translate a key into a file path.
         def key_file_path(key)
+          if key.size > FILEPATH_MAX_SIZE
+            key = Digest::MD5.hexdigest(key)
+          end
+
           fname = URI.encode_www_form_component(key)
           hash = Zlib.adler32(fname)
           hash, dir_1 = hash.divmod(0x1000)

activesupport/test/caching_test.rb

@@ -692,6 +692,11 @@ def test_clear
     assert File.exist?(filepath)
   end
 
+  def test_long_keys
+    @cache.write("a"*10000, 1)
+    assert_equal 1, @cache.read("a"*10000)
+  end
+
   def test_key_transformation
     key = @cache.send(:key_file_path, "views/index?id=1")
     assert_equal "views/index?id=1", @cache.send(:file_path_key, key)