rails: Memory leak in development

Steps to reproduce

Add lines to ApplicationController:

  after_action do
    logger.info 'Leaked: ' +
      view_paths.first.instance_variable_get(:@cache).instance_variable_get(:@data).size.to_s
  end

Refresh page few times. See the number is increasing.

It’s related to #20384. Digests are cleared, but not cache objects. I haven’t found easy way to clear all caches, as every controller seems to have its own.

Expected behavior

Cache size should not be incremented infinitely.

Actual behavior

It’s incremented infinitely.

System configuration

Rails version: 5.0.0.1

Ruby version: 2.3