mongodb/mongo-perl-driver — pull request #80 by dagolden (2013-09-16 17:38:58+00:00)
Title: Make find_and_modify die on error

run_command returns a string for errors. This commit detects it
and rethrows. Otherwise find_and_modify dies trying to treat
the string as a hash reference and the original error is lost.

A better fix (with broader implications) is to have run_command throw
errors instead of returning strings for errors.