MemoryStore#fetch with 7.1 defaults can't set expires_at via block opts

[mroach]

Steps to reproduce

In a Rails app, use the following config:

config.cache = :memory_store
config.load_defaults(7.1)

Now, use Rails.cache.fetch passing a block and try to set options.expires_at. An ArgumentError is raised:

ArgumentError: Either :expires_in or :expires_at can be supplied, but not both

Additionally, the cache store's options are mutated with the expries_at option set in the block

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", github: "rails/rails", branch: "main"
end

require "active_support"
require "active_support/core_ext/object/blank"
require "minitest/autorun"

class TestApp < Rails::Application
  config.root = "/tmp"
  config.eager_load = false
  config.cache = :memory_store
  config.load_defaults(7.1)

  Rails.application.initialize!
end

class BugTest < Minitest::Test
  def test_memory_store_fetch_opts
    Rails.cache.fetch(SecureRandom.alphanumeric) do |_key, opts|
      opts.expires_at = 1.minute.from_now
      Time.now.to_s
    end
  ensure
    puts "Cache options are now #{Rails.cache.options}"
  end
end

Expected behavior

Cache is written with the given expires_at value.

Actual behavior

An ArgumentError is raised saying that we're trying to set two options. Rails.cache options are mutated with the options from the block.

# Running:

Cache options are now {:compress=>true, :compress_threshold=>1024, :expires_at=>Thu, 26 Oct 2023 12:58:56.191690312 UTC +00:00}
E

Error:
BugTest#test_memory_store_fetch_opts:
ArgumentError: Either :expires_in or :expires_at can be supplied, but not both

System configuration

Rails version: main

Ruby version: 3.2.2

[HolyWalley]

If no one minds, I'll check it out

[HolyWalley]

I don't find this issue is related to config.load_defaults(7.1), you can try with 7.0, 6.0 or other, it's reproducible on main.

The problem is in this merge

when we delete expires_at from hash here we delete it from call_options, which is different object from options (which still contains expires_at), so, merge leads to this behaviour

I'll work on fix

[HolyWalley]

Well, turns out the actual problem is a bit more serious (but easy to fix)

method merge_options in case if no call_options were specified returns Store@options as a result of merge, this way when we change our options in block, what we actually do - we change global rails cache options. I'll make a PR with a fix soon