Document :mem_cache_store
$MEMCACHE_SERVERS
incompatibility
#764
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This adds a warning to
History.md
and3.0-Upgrade.md
to help prevent mistakes when migrating from:dalli_store
to:mem_cache_store
.:dalli_store
falls back to$MEMCACHE_SERVERS
if no addresses are given, whereas:mem_cache_store
goes straight tolocalhost:11211
.This is not immediately obvious, especially to users not providing any custom options, and makes it easy to accidentally effectively disable caching entirely (if
localhost:11211
is not a memcached server).Note that rails/rails#40420 would add support for
$MEMCACHE_SERVERS
. Nonetheless, I think it would make sense to get this documentation out ASAP to prevent accidents. If the PR is accepted, it would make sense to follow up with a message mentioning specific Rails versions, once it has made it into a release.