basho/riak_kv — pull request #252 by beerriot (2011-11-29 20:03:35+00:00)
Title: Improve MR Error Messages (AZ935)

This PR "improves" MapReduce error messages.

At the moment, "improves" means, "gets more information out in the HTTP response." I'm interested in feedback about whether or not this is the right information to expose, and whether or not it's exposed in a useful format. If both aspects are +1, similar changes should also be made to the PB response.

Side note: There was early discussion about translating errors like `bad_encoding` to more verbose English like "The input contained bytes that were not valid UTF-8 characters." This was dropped in favor of just changing the error atom to `bad_utf8_character_code` to keep things simpler. The new atom should be descriptive, yet unique enough to describe further in other Google-reachable contexts, like the wiki.