Preserve key order passed to ActiveSupport::CacheStore#fetch_multi

fetch_multi(*names) now returns its results in the same order
as the `*names` requested, rather than returning cache hits
followed by cache misses.

1 files changed, 9 insertions, 9 deletions

diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
index e8518645d9..30a69c550b 100644
--- a/activesupport/lib/active_support/cache.rb
+++ b/activesupport/lib/active_support/cache.rb
@@ -438,18 +438,18 @@ module ActiveSupport
         options = merged_options(options)
 
         instrument :read_multi, names, options do |payload|
-          read_multi_entries(names, options).tap do |results|
-            payload[:hits] = results.keys
-            payload[:super_operation] = :fetch_multi
+          reads   = read_multi_entries(names, options)
+          writes  = {}
+          ordered = names.each_with_object({}) do |name, hash|
+            hash[name] = reads.fetch(name) { writes[name] = yield(name) }
+          end
 
-            writes = {}
+          payload[:hits] = reads.keys
+          payload[:super_operation] = :fetch_multi
 
-            (names - results.keys).each do |name|
-              results[name] = writes[name] = yield(name)
-            end
+          write_multi(writes, options)
 
-            write_multi writes, options
-          end
+          ordered
         end
       end