SoftCache NullPointerException in has? with many threads
Description
"cell" can be null on this call to SoftReference.get():
https://github.com/clojure/core.cache/blob/master/src/main/clojure/clojure/core/cache.clj#L501
If the cache did not contain "item" in the call to (get cache item) in the let binding, but another thread pre-empts and adds it before the subsequent call to contains?, we'll attempt to call .get() on nil.
Would it perhaps be sufficient to just check whether cell is nil instead of calling contains? in the check on the previous line?
Environment
Linux, Oracle JRE 1.6
Activity
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Ambrose Bonnaire-Sergeant
August 4, 2014, 9:56 PM
Paul Stadig
February 9, 2013, 12:13 PM
Good catch!
This is rather simple to reproduce:
The attached patch fixes the issue, by not referring back to the cache after attempting to pull out a SoftReference.
