[CMEMOIZE-3] snapshot assumes too much about a CacheProtocol implementation Created: 13/Dec/11 Updated: 14/Dec/11 Resolved: 14/Dec/11
|Patch:||Code and Test|
I believe this line https://github.com/clojure/core.memoize/blob/9bdf608af8bbf4a753fc19758446dd821cb45979/src/main/clojure/clojure/core/memoize.clj#L72 assumes too much about implementations of CacheProtocol, namely that they have a field named 'cache'.
The first call to .cache makes sense, since PluggableMemoization has a 'cache' field, but the second call to .cache assumes that any implementation of CacheProtocol that PluggableMemoization wraps will have a 'cache' field.
I ran into this issue when I desired to have a cache that ignores nils, so I attempted to wrap the TTLCache with an implementation of CacheProtocol that would not cache nil values. Calls to snapshot failed since it was trying to access a 'cache' field on my NoNilCache.
I suspect that the outer call to .cache could be replaced with a call to seq, since defcache adds an implementation of seq to each cache implementation which should pull out the keys/values from the cache.
I'd be glad to work up a patch given that I'm not off base in my assumptions.
|Comment by Fogus [ 13/Dec/11 3:08 PM ]|
The better assumption is that the underlying caches are associative. Thanks for reporting and a patch would be wonderful.
|Comment by Paul Stadig [ 13/Dec/11 4:16 PM ]|
Added test and removed one layer of calls to .cache. I tested this against my code base, and it fixes the issue I was seeing.
|Comment by Paul Stadig [ 13/Dec/11 4:28 PM ]|
Updated patch. The tests worked before by throwing an exception on failure, but I updated it by adding an is assertion.