2.5. I have a "xyz" (some) problem with Vim. How do I determine it is a
problem with my setup or with Vim? / Have I found a bug in Vim?
First, you need to find out, whether the error is in the actual
runtime files or any plugin that is distributed with Vim or whether it
is a simple side effect of any configuration option from your .vimrc
or .gvimrc. So first, start vim like this:
vim -u NONE -U NONE -N -i NONE
this starts Vim in nocompatible mode (-N), without reading your
viminfo file (-i NONE), without reading any configuration file (-u
NONE for not reading .vimrc file and -U NONE for not reading a .gvimrc
file) or even plugin.
If the error does not occur when starting Vim this way, then the
problem is either related to some plugin of yours or some setting in
one of your local setup files. You need to find out, what triggers the
error, you try starting Vim this way:
vim -u NONE -U NONE -N
If the error occurs, the problem is your .viminfo file. Simply delete
the viminfo file then. If the error does not occur, try:
vim -u ~/.vimrc --noplugin -N -i NONE
This will simply use your .vimrc as configuration file, but not load
any plugins. If the error occurs this time, the error is possibly
caused by some configuration option inside your .vimrc file. Depending
on the length of your vimrc file, it can be quite hard to trace the
origin within that file.
The best way is to add :finish command in the middle of your .vimrc.
Then restart again using the same command line. If the error still
occurs, the bug must be caused because of a setting in the first half
of your .vimrc. If it doesn't happen, the problematic setting must be
in the second half of your .vimrc. So move the :finish command to the
middle of that half, of which you know that triggers the error and
move your way along, until you find the problematic option. If your
.vimrc is 350 lines long, you need at a maximum 9 tries to find the
offending line (in practise, this can often be further reduced, since
often lines depend on each other).
If the problem does not occur, when only loading your .vimrc file, the
error must be caused by a plugin or another runtime file (indent
autoload or syntax script). Check the output of the :scriptnames
command to see what files have been loaded and for each one try to
disable each one by one and see which one triggers the bug. Often
files that are loaded by vim, have a simple configuration variable to
disable them, but you need to check inside each file separately.