Merge pull request #706 from rails/synchronize

Bring back `Spring::Watcher::Abstract#synchronize`

Author: byroot

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Next Release
 
+* Bring back `Spring::Watcher::Abstract#synchronize` method to fix compatibility with `spring-watcher-listen`.
+
 ## 4.1.2
 
 * Drop dependency on `mutex_m`. Avoid issues with loading the wrong version before bundler kicks in.

lib/spring/watcher/abstract.rb

@@ -22,6 +22,11 @@ def initialize(root, latency)
         @on_debug    = nil
       end
 
+      def synchronize(&block)
+        # Used by some gems.
+        @mutex.synchronize(&block)
+      end
+
       def on_debug(&block)
         @on_debug = block
       end