Rails: Fixing the memory leak in prepend_view_path

Recently we detected a memory leak in one of our applications. Hunting it down, we found that the memory leak was located in Rails' #prepend_view_path. It occurs when the instance method prepend_view_path is called in each request, which is a common thing in a multi-tenant application.

This is not a new memory leak. It was first reported in in 2014 Archive . Five years later, Frederick cheung wrote in detail how he chased down this memory leak Archive . Last year, mudge added some dev improvement Archive .

We took their solution a little further to prevent the leak at its root. With the attached module, you can just use #prepend_view_path as before.

Known affected Rails versions (maybe more): Rails 4.0 - 6.1