Changing choice loss count update to be atomic, prevent one type of race case

Dhruv Kapadia
1 parent 0d1f1e29
Showing 2 changed files with 4 additions and 3 deletions Show diff stats
app/models/choice.rb
spec/models/choice_spec.rb
@@ -22,9 +22,9 @@ class Choice &lt; ActiveRecord::Base
   #attr_accessor :data
  
   def lose!
-    self.loss_count += 1 rescue (self.loss_count = 1)
-    self.score = compute_score
-    self.save!
+    Choice.increment_counter(:loss_count, self.id)
+    self.loss_count +=1 # reflect the update just done above, so score is correct
+    Choice.update(self.id, :score => compute_score)
   end
  
   def win!
@@ -108,6 +108,7 @@ describe Choice do
           @winning_choice.score.should be_close(67, 1)
      end
      it "should update score on a loss" do
+	  @losing_choice.reload
           @losing_choice.score.should be_close(33,1)
      end
      it "should update win count on a win" do
...	...	@@ -22,9 +22,9 @@ class Choice < ActiveRecord::Base
22	22	#attr_accessor :data
23	23
24	24	def lose!
25		- self.loss_count += 1 rescue (self.loss_count = 1)
26		- self.score = compute_score
27		- self.save!
	25	+ Choice.increment_counter(:loss_count, self.id)
	26	+ self.loss_count +=1 # reflect the update just done above, so score is correct
	27	+ Choice.update(self.id, :score => compute_score)
28	28	end
29	29
30	30	def win!
...	...
...	...	@@ -108,6 +108,7 @@ describe Choice do
108	108	@winning_choice.score.should be_close(67, 1)
109	109	end
110	110	it "should update score on a loss" do
	111	+ @losing_choice.reload
111	112	@losing_choice.score.should be_close(33,1)
112	113	end
113	114	it "should update win count on a win" do
...	...