advanced patterns with Mutex in Ruby 3.1 - Blocking Threads in a Simple Counter
I'm trying to figure out I'm stuck on something that should probably be simple... I'm experiencing an scenario with thread safety when using a `Mutex` in Ruby 3.1. I have a simple counter that should be incremented by multiple threads, but it appears that some increments are being lost. After reviewing my implementation, I suspect that the `Mutex` usage might not be correctly preventing race conditions. Here’s the code: ```ruby require 'thread' class Counter def initialize @count = 0 @mutex = Mutex.new end def increment @mutex.synchronize do @count += 1 end end def value @count end end counter = Counter.new threads = [] 10.times do threads << Thread.new { 1000.times { counter.increment } } end threads.each(&:join) puts "Final counter value: #{counter.value}" ``` When I run this code, I expect the final counter value to be `10000`, but I often see values like `9998` or `9999`. I’ve double-checked the `synchronize` block, and it appears that it should be protecting access to the `@count` variable. I'm not using any other threads manipulating this variable outside of the `increment` method. I also tried wrapping the entire increment operation in the `synchronize` block, but it didn't change the outcome. Could it be that the question lies elsewhere, like thread scheduling or a bug in Ruby 3.1? What am I missing here? Any insights into debugging this threading scenario would be greatly appreciated! This is part of a larger CLI tool I'm building. Any help would be greatly appreciated! This is for a web app running on Ubuntu 22.04. I'd love to hear your thoughts on this.