Vim doesn't use the correct indentation in Python files

Question

I have encountered something that I have never seen before in Vim. While I was tentatively modifying some of the source code for software I've been planning to work on, I noticed vim was displaying incorrect spacing for the line of code that I added. Gedit shows the code with the correct spacing. I know Gedit has the correct spacing because the Python code delivers errors if I change the code in Vim to be where it appears to belong within the Vim window. I have attached the Images below. The line that I added is the line that says: print "I am about to evaluate a factorial". I have included my short .vimrc file as well. Has anyone seen this? I have been using vim for months now and can't recall anything like this ever occuring.

• Vim (Incorrect):

  

• Gedit (Correct):

  

• Vimrc:

  

Answer 1

It gets reset by the Python filetype plugin; from /usr/share/vim/vim74/ftplugin/python.vim:

" As suggested by PEP8.
setlocal expandtab shiftwidth=4 softtabstop=4 tabstop=8

This file is loaded every time a Python file is loaded.

To override it add this in your vimrc:

augroup python
    autocmd!
    " Add shiftwidth and/or softtabstop if you want to override those too.
    autocmd FileType python setlocal noexpandtab tabstop=4
augroup end

This will get loaded after the ftplugin file, overriding the settings from there.

I would recommend against using tabs in Python files, as the community standard is to use spaces.

Answer 2

Solution for me was to add this line after the filetype plugin on into my ~/.vimrc file

filetype plugin on
autocmd FileType python setlocal noexpandtab shiftwidth=4 softtabstop=4

Answer 3

Because the file python.vim, path in Debian 9 /usr/share/vim/vim81/ftplugin/python.vim, contains the following code

if !exists("g:python_recommended_style") || g:python_recommended_style != 0
    " As suggested by PEP8.
    setlocal expandtab shiftwidth=4 softtabstop=4 tabstop=8
endif

the best to turn it off is to put

let g:python_recommended_style=0

into .vimrc and the code would not execute at all, because the plugin is usually executed after .vimrc.

Another solution is to create ~/.vim/after/ftplugin/python.vim hook as suggested in https://vi.stackexchange.com/a/13538/41302