joyent/node — pull request #5951 by bnoordhuis (2013-07-30 21:11:54+00:00)
Title: util: don't throw on circular %j input to format()

Don't throw an exception when the argument to %j is an object that
contains circular references, it's not helpful. Catch the exception
and return the string '[Circular]'.

Suggested reviewer: @tjfontaine for no particular reason.