Strip escape sequences in diff output

[zharmany]

Hi there,

I've been recently getting odd errors when stripping whitespace upon save. I eventually diagnosed this as being related to setting my Vim shell to be a bash login shell, via let &shell='bash -l'.

What happens is that during the course of sourcing my dotfiles for my fancy prompt and such, the tput sgr0 command is issued, which causes the printing of escape characters that reset any color / styling effect for text.

This messes up the output of the diff command in vim-better-whitespace, the line being

silent! echo system(s:diff_cmd.' '.shellescape(expand('%')).' -', join(getline(1, line('$')), "\n") . "\n")

For now, I'm just going to comment out the tput sgr0 line in my .bash_profile and hope for the best, but I'm wondering if there's a more robust way to get the diff output (avoiding the shell altogether, or strip the escape sequences). I do realize that this more of a me problem than a you problem.

[Cimbali]

Hi @zharmany, I think that’s a tricky problem. Do you get it only with better whitespace or with all system()-based commands?

The g:diff_binary option can maybe help you here, it’s what’s used to build the diff command. Maybe setting the path to diff directly helps?

let g:diff_binary='/usr/bin/diff --color=never'

Otherwise you can maybe use it to insert something before the diff command that clears up any garbage thrown out by your login script? Not sure how to go about that though.

Also note that the diff command is only used to strip whitespace on modified lines only. You can disable that option and better-whitespace will strip all lines of the file.

[zharmany]

Thanks for the reply.

In my situation, it was with all system() commands -- as it was capturing the output of something in my .bash_profile prior to capturing the output of the actual command. E.g., even echo system('command pwd') would wind up capturing extra escape characters.

With that said, I don't think changing the diff_binary would help, because it's the output prior to any diff command.

There's probably a few different ways to solve this, but I'm not versed enough in Vimscript to know what would be the appropriate way to go.

Thanks for the suggestion about modified lines, but that's precisely one of the awesome features I like :). I work on a shared codebase with folks that are not as persnickety as me, so I'd be making all sorts of whitespace changes in the codebase.

[Cimbali]

I think the only way to fix this is to make your .bash_profile entirely silent.

You can probably make it silent only for non-interactive shells and let it print as usual for interactive sessions.
So for example, replacing tput sgr0 with [[ $- == *i* ]] && tput sgr0'. Also you maybe don’t need to set your fancy prompt at all in a non-interactive shell?