Only call .getFileName and .getLineNumber when the caller is not nil.

[kennyjwilli]

When working with Spymemcached I run into a NPE caused by the caller (here) bein nil.

This PR fixes the issue by only including ?:file and ?line in the log! call when the caller is not nil.

[rufoa]

Thanks for the bug report and PR @kennyjwilli! I'll check it out.

I'm pretty sure caller# should never be nil so I wonder if the root cause is actually something else. Do you have a test case you can share that exhibits this problem please?

[kennyjwilli]

The issue is with Datomic and Spymemcached. I created a repo that can easily reproduce the exception: https://github.com/kennyjwilli/memcached-datomic-npe. The README has instructions to reproduce the exception.

[rufoa]

Thanks, that was very helpful!

The root cause seems to be a botched refactoring in Spymemcached:
https://github.com/couchbase/spymemcached/blob/730fe4f285887ed074c78da84ef58a85bf8abd4d/src/main/java/net/spy/memcached/compat/log/Log4JLogger.java#L99 (among several other places)

Note that the package name should now be net.spy.memcached.compat.log rather than net.spy.compat.log

---

One of us should probably make a PR to fix that, but in the meantime I'll come up with a fix for slf4j-timbre to avoid the issue as best I can.

Unfortunately your proposed (cond-> trick won't work here because timbre/log! is a macro that tries to destructure the form at macro expansion time, so it needs a real map not a sexpr that evals to a map.

[kennyjwilli]

Gotcha. I don't know enough about Log4J to put together a good PR. Do you only need to change the package name to net.spy.memcached.compat.log?

Yeah when writing the patch I didn't realize log! was a macro. After having that realization, I used the cond-> approach which removed the exception for me.

[rufoa]

Done the PR, yeah it just needed a search and replace: dustin/java-memcached-client#48

[rufoa]

Pushed v0.3.8 to clojars, please confirm it fixes the issue

[kennyjwilli]

Yep that fixes it! Thanks for the quick fixes.