http://dev.clojure.org/jira This file is an XML representation of an issue en-us 4.4 649 25-07-2011 http://dev.clojure.org/jira/browse/CCACHE-28 core.cache <p>"cell" can be null on this call to SoftReference.get():<br/> <a href="https://github.com/clojure/core.cache/blob/master/src/main/clojure/clojure/core/cache.clj#L501">https://github.com/clojure/core.cache/blob/master/src/main/clojure/clojure/core/cache.clj#L501</a></p> <p>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.</p> <p>Would it perhaps be sufficient to just check whether cell is nil instead of calling contains? in the check on the previous line?</p> Linux, Oracle JRE 1.6 CCACHE-28

SoftCache NullPointerException in has? with many threads

Defect Major Open Unresolved Fogus James Aley Wed, 24 Oct 2012 08:42:28 -0500 Sat, 9 Feb 2013 06:27:03 -0600 0 0 <p>Good catch!</p> <p>This is rather simple to reproduce:</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java">(use 'clojure.core.cache) (def cache (soft-reference-cache {})) (def mutator (<span class="code-object">Thread</span>. #(loop [] (assoc cache :foo :bar) (dissoc cache :foo) (recur)))) (.start mutator) (loop [] (has? cache :foo) (recur))</pre> </div></div> <p>The attached patch fixes the issue, by not referring back to the cache after attempting to pull out a SoftReference.</p> Global Rank Patch Code