This reverts commit abe915f2.

This broke all existing keys and it's wrong anyway. The array is just there as a convenience option for building the string. It's intentional that [ "stuff"] and "stuff" generates the same key.

minor

In short:
expand_cache_key(element) should not equal expand_cache_key([element])

This way a fragment cache key for an index page with only a single
element in the collection is different than a fragment cache for a
typical show page for that element.

Add ActiveSupport::Cache::NullStore to expose caching interface without actually caching for development and test environments.

`nil` and `false` both expand to `""` (empty string), while `true` expands to
`"true"`; `false` should expand to `"false"`

`cache_key` method is never called when the argument is a 1-element array
with something that responds to `cache_key`

tests predicates according to the boolean interpretation of their return value, not expecting specifically true or false

Respecting Genuine assert_equal false Edition

Revert "tests predicates according to the boolean interpretation of their return value, not expecting specifically true or false"

Reason: there were some genuine tests for false when
reading values, going to revise those ones.

This reverts commit a539a5e3.

tests predicates according to the boolean interpretation of their return value, not expecting specifically true or false

Tests were failing on Travis-CI.

This reverts commit 79d01a8f, reversing
changes made to b838570b.

Added fix so that file store does not raise an exception when cache dir does not exist yet. This can happen if a delete_matched is called before anything is saved in the cache.

Updated existing test that fails with this fix (8d63678d).  Before the fix the test was giving a false positive, because file_store.key_file_path would return an empty filename (i.e. test/tmp_cache/4D0/F4D rather than test/tmp_cache/4D0/F4D/xxxx…).

Even though the fix referenced above divides the filename into directories to prevent it from being too long, it seems that 1000 characters will always raise an error, so reducing the key size to 900).

Fixed issue in file store where it could create a filename that was too long for the file system.  (https://github.com/rails/rails/issues/3072)

Port from 3-1-stable

do not test explicit equality of predicate methods, they should be allowed to return truthy or falsey objects

Fix FileStore cache incorrectly regenerating its key from a pathname when a regexp is used in expire_fragment

[#5850 state:committed]
Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

code gardening: we have assert_(nil|blank|present), more concise, with better default failure messages - let's use them

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Make use of assert_equal to test equallity between object assert expects and object and a message of error

[#4611 state:committed]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

All Caches

* Add default options to initializer that will be sent to all read, write, fetch, exist?, increment, and decrement
* Add support for the :expires_in option to fetch and write for all caches. Cache entries are stored with the create timestamp and a ttl so that expiration can be handled independently of the implementation.
* Add support for a :namespace option. This can be used to set a global prefix for cache entries.
* Deprecate expand_cache_key on ActiveSupport::Cache and move it to ActionController::Caching and ActionDispatch::Http::Cache since the logic in the method used some Rails specific environment variables and was only used by ActionPack classes. Not very DRY but there didn't seem to be a good shared spot and ActiveSupport really shouldn't be Rails specific.
* Add support for :race_condition_ttl to fetch. This setting can prevent race conditions on fetch calls where several processes try to regenerate a recently expired entry at once.
* Add support for :compress option to fetch and write which will compress any data over a configurable threshold.
* Nil values can now be stored in the cache and are distinct from cache misses for fetch.
* Easier API to create new implementations. Just need to implement the methods read_entry, write_entry, and delete_entry instead of overwriting existing methods.
* Since all cache implementations support storing objects, update the docs to state that ActiveCache::Cache::Store implementations should store objects. Keys, however, must be strings since some implementations require that.
* Increase test coverage.
* Document methods which are provided as convenience but which may not be universally available.

MemoryStore

* MemoryStore can now safely be used as the cache for single server sites.
* Make thread safe so that the default cache implementation used by Rails is thread safe. The overhead is minimal and it is still the fastest store available.
* Provide :size initialization option indicating the maximum size of the cache in memory (defaults to 32Mb).
* Add prune logic that removes the least recently used cache entries to keep the cache size from exceeding the max.
* Deprecated SynchronizedMemoryStore since it isn't needed anymore.

FileStore

* Escape key values so they will work as file names on all file systems, be consistent, and case sensitive
* Use a hash algorithm to segment the cache into sub directories so that a large cache doesn't exceed file system limits.
* FileStore can be slow so implement the LocalCache strategy to cache reads for the duration of a request.
* Add cleanup method to keep the disk from filling up with expired entries.
* Fix increment and decrement to use file system locks so they are consistent between processes.

MemCacheStore

* Support all keys. Previously keys with spaces in them would fail
* Deprecate CompressedMemCacheStore since it isn't needed anymore (use :compress => true)

[#4452 state:committed]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

Drop expires argument from call to @data in MemCacheStore so it works with memcache-client and memcached gems, as advertised [#3672 state:resolved]
Signed-off-by: Nwycats <wycats@gmail.com>