While working with my new employer (in 2011) I noticed a minor but recurring issue in our application. We had been storing flash[:notice] messages in most of our actions but were not using that flash message anywhere. This was resulting in the flash message showing up at in-appropriate times. What I was unaware of was a slightly different call which is flash.now[:notice]. This results in the flash only having a lifespan of the through the next request.
This is just a quick bit that I learned early in my Ruby career and always found interesting.
Symbols Are Memory Leaks
So is this the end of the world?
No
Symbols are a unique thing in ruby. It’s immutable, constant and unique. You can re-use the same Symbol over and over without allocating extra memory. As opposed to using a String over and over which will allocate memory with each instance.
