How to run isort via ALE in Vim?

Question

I want to set up isort to be used in Vim via the ALE plugin. I've added this shortcut to my .vimrc:

nnoremap <leader>I :ALEFix isort<CR>

However, when I activate it nothing happens. I have isort installed both globally and in the virtualenv. Could anyone give me a hint how to debug/solve this issue?

Answer 1

From ALE's README.md

ALE can fix files with the ALEFix command. Functions need to be configured either in each buffer with a b:ale_fixers, or globally with g:ale_fixers. The recommended way to configure fixers is to define a List in an ftplugin file.

The proper way of configuring isort is by setting g:ale_fixers in your vimrc / init.vim or b:ale_fixers in ftplugin/python.vim.

E.g.

" setting it globally
let g:ale_fixers = {
            \ 'python': ['black', 'isort'],
            \ }

Any command line options you want to pass to isort you do it by setting g:ale_python_isort_options.

let g:ale_python_isort_options = '--profile black -l 100'

If you want to automatically fix files when you save them, you need to turn a setting on in vimrc.

" Set this variable to 1 to fix files when you save them.
let g:ale_fix_on_save = 1