Rails.cache.write returns false with MemCacheStore even if the operation
was successful done.
result = Rails.cache.write('key', 'value')
Rails.cache.read('key') # => value
puts result # => false
The problem is trivial: MemCache#set doesn't return any result, so the
check performed by MemCacheStore#write will always fail.
The described behavior is related to memcache-client (1.5.0). I noticed
differences between the gem installed on my machine and the bundled one:
memcached-client (1.5.0) gem
memcached-client (1.5.0) bundled
I created a ticket and attached a patch to it