Editing Bisecting

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Debugging Vim problems is a classic example of working with a system that is often too complex to sit back, stroke your beard, and reason your way through. Perhaps it is the "Hello World" of this class of problems?

So learn about bisecting, aka [https://c2.com/cgi/wiki?BinaryChop Binary Chop], aka [http://www.st.cs.uni-saarland.de/dd/ Delta Debugging], aka [[wikipedia:Divide_and_conquer_algorithm|Divide and Conquer]].

When you do bisect, you have to start with a ☺ version and a ☠ version. Then you pick a point in between the two, and test to see if it's ☺ or ☠. After you've done that, you've moved the two closer together, so your search space is smaller.

When you are debugging, you have your "☠" version automatically, because you've got something that's not working currently.

An important test in Vim is to use <code>vim -u NONE</code> (which skips almost all of the startup sequence) to see if the problem reproduces there or not.

* If debugging a <code>.gvimrc</code> problem, you might want to try<code>gvim -U NONE</code> after you determine the status of the lower-cased version.

#vim's bairui has a plan for a script, [https://rubygems.org/gems/bisectly bisectly], that will help you with it, but at the moment his batsuit is at the batdrycleaners, so we're batwaiting with bated batbreath.

<pre>

mv ~/.vimrc ~/.vim /tmp && mkdir ~/.vim

</pre>

<pre>

mv /tmp/.vimrc ~ && vim

</pre>

And test the behavior again. (Note that tools like Pathogen and the Vim-Addon-Manager will complicate this first step a bit). If the problem reappears descend into your ~/.vimrc and comment out half of it (with something like 50%:.,$s/^/" ) and find the section that is causing the problem.