More on Vim with ruby crashing

I finally figured out all the reasons why Vim keeps crashing on me. I started collecting info in OS X Vim with Ruby crashes but there were still crashes happening.

It’s an interesting story. Grab a beer and pull up a chair…

So there turns out to be due to custom versions of Ruby that I use a lot, usually via RVM (but not always).

There are two ways Vim can crash.

Wrong ruby syndrome

The first is because when I compiled vim (using the --enable-rubyinterp option) it grabbed whatever ruby is first in my PATH. Usually this is a ruby compiled by RVM.

One of the things RVM can do (and usually does) is compile custom libraries (such as libyaml or libreadline) to make the ruby work better. This is great for using raw ruby, but within vim it causes it to crash because it finds the non-RVM version of the library, loads it, and crashes.

In some cases vim and ruby are compiled with incompatible CFLAGS or even with different compilers (clang vs. gcc).

The symptom for this is a crash the instance Vim tries to do anything with its built-in ruby interpreter.

This fix for this is when compiling vim to specify the ruby to use. For example:

./configure ... --enable-rubyinterp --with-ruby-command=/usr/bin/ruby

Wrong gem syndrome

This one may or may not causes crashes, depending on the gems you have. If you only have pure-ruby gems then it may never cause a crash.

However, if you have GEM_HOME and GEM_PATH set (which RVM does for you) then when you run Vim and try to load any gems it’ll look in those paths.

If any of the gems to be loaded are compiled incompatibly (as above) then when Vim’s ruby interpreter loads them, vim will crash. mysql2 and nokogiri are two that cause vim to crash regularly for me in this case.

The solution is to unset GEM_HOME and GEM_PATH before running vim. I have it aliased in my ~/.zshrc file:

alias ex='env -u GEM_PATH -u GEM_HOME command ex'
alias gview='env -u GEM_PATH -u GEM_HOME command gview'
alias gvim='env -u GEM_PATH -u GEM_HOME command gvim'
alias gvimdiff='env -u GEM_PATH -u GEM_HOME command gvimdiff'
alias gvimex='env -u GEM_PATH -u GEM_HOME command gvimex'
alias mview='env -u GEM_PATH -u GEM_HOME command mview'
alias mvim='env -u GEM_PATH -u GEM_HOME command mvim'
alias mvimdiff='env -u GEM_PATH -u GEM_HOME command mvimdiff'
alias mvimex='env -u GEM_PATH -u GEM_HOME command mvimex'
alias rview='env -u GEM_PATH -u GEM_HOME command rview'
alias rvim='env -u GEM_PATH -u GEM_HOME command rvim'
alias view='env -u GEM_PATH -u GEM_HOME command view'
alias vim='env -u GEM_PATH -u GEM_HOME command vim'
alias vimdiff='env -u GEM_PATH -u GEM_HOME command vimdiff'
alias vimtutor='env -u GEM_PATH -u GEM_HOME command vimtutor'
alias xxd='env -u GEM_PATH -u GEM_HOME command xxd'

Rather gross but it works.

The downside of doing this is that things like omnicomplete will be looking at the wrong list of Gemfiles. So either you get no completion for these gems, or you need run bundle install with your system ruby, or you have to risk crashing.

Final thoughts

There has to be a better way to handle this. I’m unclear how vim is loading the ruby interpreter, but I suspect that ruby just isn’t designed right to allow this work well.

I opened bug 17313 with Homebrew, but the more I think about this the more I think it is a Vim and Ruby problem.

Ciao!