[COUCHDB-354] Ungraceful behaviour if view returns a function

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Won't Fix
• Component/s: JavaScript View Server
• Environment: {"couchdb":"Welcome","version":"0.10.0a776990"}
• Skill Level: Regular Contributors Level (Easy to Medium)
• Assignee: Unassigned
• Reporter: Brian Candler
• Created: 21/May/09 09:41
• Updated: 02/Sep/18 06:26
• Resolved: 02/Sep/18 06:26

Description

If a typo in a view definition causes it to return a function instead of a normal value:

• the view server crashes
• you get a huge Erlang barf in the log with worrying messages like "OS process timed out" and "brutal kill"

I got all this just by accidentally writing "vs.shift" instead of "vs.shift()"

The fundamental problem is that a function cannot be serialised in toJSON, but the error message is not helpful:

OS Process Log Message: Error converting object to JSON: TypeError: {Array:function (v) {var ... snip loads ... "Object"] is not a function

When actually the problem is that the object I was trying to convert was a function

I will attach some code which replicates this, and the barf generated.

Of course this is entirely down to user error in an invalid map/reduce function. However there's already a clean error for 'undefined', maybe this could be done for 'function' too (or indeed any non-serialisable entity)