Raise an error if FileUpdateChecker#execute is called with no block

activesupport/lib/active_support/evented_file_update_checker.rb

@@ -74,7 +74,11 @@ module ActiveSupport
 
     def execute
       @updated.make_false
-      @block.call
+      if @block.nil?
+        raise ArgumentError, "no block given: #{self.inspect}, please pass a block when you initialize #{self.class}"
+      else
+        @block.call
+      end
     end
 
     def execute_if_updated

activesupport/lib/active_support/file_update_checker.rb

@@ -74,7 +74,11 @@ module ActiveSupport
     def execute
       @last_watched   = watched
       @last_update_at = updated_at(@last_watched)
-      @block.call
+      if @block.nil?
+        raise ArgumentError, "no block given: #{self.inspect}, please pass a block when you initialize #{self.class}"
+      else
+        @block.call
+      end
     ensure
       @watched = nil
       @updated_at = nil

activesupport/test/file_update_checker_shared_tests.rb

@@ -273,4 +273,11 @@ module FileUpdateCheckerSharedTests
     assert checker.execute_if_updated
     assert_equal 2, i
   end
+
+  test "execute raises an ArgumentError if no block given" do
+    checker = new_checker([])
+    assert_raise ArgumentError do
+      checker.execute
+    end
+  end
 end