stack trace from "brew update"

stacktrace

$ brew doctor
Warning: Your Homebrew is outdated.
You haven't updated for at least 24 hours, this is a long time in brewland!
To update Homebrew, run `brew update`.
$ brew update
Error: undefined method `to_sym' for nil:NilClass
Please report this bug:
    https://github.com/mxcl/homebrew/wiki/troubleshooting
/usr/local/Library/Homebrew/cmd/update.rb:134:in `report'
/usr/local/Library/Homebrew/cmd/update.rb:132:in `each_line'
/usr/local/Library/Homebrew/cmd/update.rb:132:in `report'
/usr/local/Library/Homebrew/cmd/update.rb:36:in `update'
/usr/local/Library/brew.rb:91:in `send'
/usr/local/Library/brew.rb:91
$ brew update
Already up-to-date.
$ brew doctor
Your system is ready to brew.
$ brew --config
HOMEBREW_VERSION: 0.9.5
ORIGIN: https://github.com/mxcl/homebrew
HEAD: 36ba8e6805c9d5a00dc4c33d28b5c2728dc673db
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CELLAR: /usr/local/Cellar
CPU: 8-core 64-bit haswell
OS X: 10.9-x86_64
Xcode: 5.0.2
CLT: 5.0.1.0.1.1382131676
Clang: 5.0 build 500
X11: N/A
System Ruby: 1.8.7-358
Perl: /usr/bin/perl
Python: /usr/bin/python
Ruby: /usr/bin/ruby => /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby