Fix RedisCacheStore#write_multi to properly update the local store.

[casperisfine]

RedisCacheStore specialises write_multi to use mset when possible, but it didn't update the local cache accordingly.

Unless I'm mistaken, I think the bug was present in the initial version #31134

cc @jeremy

[eugeneius]

I don't think we can use local_cache directly here, see #38630 (comment).

How about overriding write_multi_entries in the LocalCache module to clear the entries' keys?

rails/activesupport/lib/active_support/cache/strategy/local_cache.rb

Line 128 in 4b4895e

def read_multi_entries(keys, **options)

[casperisfine]

We can, but we'll do the work multiple times in most cases as except for this one special cache for redis, write_multi_entries is:

        def write_multi_entries(hash, **options)
          hash.each do |key, entry|
            write_entry key, entry, **options
          end
        end

But given the restrictions on that specialized write_multi (only used if no expiry), I wonder if we wouldn't be better to just remove it.

[casperisfine]

That being said, "the work" is a simple Hash#[]= per key. So might not matter much.

[casperisfine]

cc @rafaelfranca what do you think?

[rails-bot]

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[rails-bot]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
Thank you for your contributions.