How do I perform a sanity check on my .vimrc from the shell programmatically?

Question

The other day I was using one of my non-interactive scripts to set up my dot files for my home directory, including my .vimrc file. This is what I had the script put into my .vimrc file:

. /etc/external/config.conf

This was before I knew vim can interpret 'source' but not '.' when sourcing external configuration. I thought my script worked well and then I got this error later when opening up vim:

search hit BOTTOM, continuing at TOPError detected while processing 
/home/demo/.vimrc:
line    1:
E486: Pattern not found: etc

It would have been really nice if I could have run some sort of sanity check on my .vimrc in my script so that I could have found out about my misconfigured settings sooner rather than later. How can I run a sanity check on my .vimrc configuration from the shell programmatically, without user interaction?

Answer 1

It might be preferable to install an external tool, configurable depending on your needs: it may even have warnings you didn't know about. I recommend vint, which I use with ale for live linting.

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But if you go down this path you need the command to fail (exit code != 0). You can achieve this with an intermediary file (instead of an inline command for readability), i.e. test.vim:

try
  source $HOME/.vimrc
  quit
catch
  cquit
endtry

The pattern (see :h :catch) should not only contain "Error detected while processing", or you would miss some messages.

Then you have to to verify if vim -u test.vim fails, for example in bash:

vim -N -u test.vim; [[ $? -ne 0 ]] && echo "Invalid .vimrc"

In my case I needed -N to avoid errors as I don't explicitly set nocompatible in my configuration.

Also, check this answer about silent mode and running Vim non-interactively.

Answer 2

vim -q fakefile >/dev/null 2>/tmp/checkforerrors; grep -q -F 'Error detected while processing ' /tmp/checkforerrors && echo '.vimrc syntax is bad' || echo '.vimrc syntax is good!!'; rm /tmp/checkforerrors

I would love to hear from some vi/vim experts about whether this command is safe and effective. Very ugly and hackish, but it seems to work well as a way to run a sanity check on my .vimrc file.