Homebrew won't brew any more

Question

On my MacMini with El Capitan I can't run brew any more. I get the following Error:

/usr/local/Library/Homebrew/config.rb:34:in `initialize': no implicit conversion of nil into String (TypeError)     from /usr/local/Library/Homebrew/config.rb:34:in `new'     from /usr/local/Library/Homebrew/config.rb:34:in `<top (required)>'     from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:54:in `require'     from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:54:in `require'     from /usr/local/Library/Homebrew/global.rb:18:in `<top (required)>'     from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:54:in `require'     from /Library/Ruby/Site/2.0.0/rubygems/core_ext/kernel_require.rb:54:in `require'     from /usr/local/Library/brew.rb:10:in `<main>' 

The permissions of /usr/local are correct.

The config.rb file, which I haven't changed looks like this:

def cache   if ENV["HOMEBREW_CACHE"]     Pathname.new(ENV["HOMEBREW_CACHE"]).expand_path   else     # we do this for historic reasons, however the cache *should* be the same     # directory whichever user is used and whatever instance of brew is executed     home_cache = Pathname.new("~/Library/Caches/Homebrew").expand_path     if home_cache.directory? && home_cache.writable_real?       home_cache     else       Pathname.new("/Library/Caches/Homebrew").extend Module.new {         def mkpath           unless exist?             super             chmod 0775           end         end       }     end   end end  HOMEBREW_CACHE = cache undef cache  # Where brews installed via URL are cached HOMEBREW_CACHE_FORMULA = HOMEBREW_CACHE+"Formula"  unless defined? HOMEBREW_BREW_FILE   HOMEBREW_BREW_FILE = ENV["HOMEBREW_BREW_FILE"] || which("brew").to_s end  # Where we link under HOMEBREW_PREFIX = Pathname.new(ENV["HOMEBREW_PREFIX"])  # Where .git is found HOMEBREW_REPOSITORY = Pathname.new(ENV["HOMEBREW_REPOSITORY"])  HOMEBREW_LIBRARY = Pathname.new(ENV["HOMEBREW_LIBRARY"]) HOMEBREW_CONTRIB = HOMEBREW_REPOSITORY/"Library/Contributions"  # Where we store built products HOMEBREW_CELLAR = Pathname.new(ENV["HOMEBREW_CELLAR"])  HOMEBREW_LOGS = Pathname.new(ENV["HOMEBREW_LOGS"] || "~/Library/Logs/Homebrew/").expand_path  HOMEBREW_TEMP = Pathname.new(ENV.fetch("HOMEBREW_TEMP", "/tmp"))  unless defined? HOMEBREW_LIBRARY_PATH   HOMEBREW_LIBRARY_PATH = Pathname.new(__FILE__).realpath.parent.join("Homebrew") end  HOMEBREW_LOAD_PATH = HOMEBREW_LIBRARY_PATH 

The same error occurs with brew, brew doctor, brew update etc.

Any ideas, what could be wrong?

Answer 1

I had the same issue - seemed to be the result of a brew update that could not complete due to permissions issues.

First I reset the repo to the latest head:

cd /usr/local/bin git reset --hard HEAD 

Then I could run:

brew doctor 

Which found permissions issues. Fixing those permissions as per instructions finally allowed me to run:

brew update