vim-flake8 is a Vim plugin that runs the currently open file through Flake8, a static syntax and style checker for Python source code. It supersedes both vim-pyflakes and vim-pep8.

Flake8 is a wrapper around PyFlakes (static syntax checker), PEP8 (style checker) and Ned's MacCabe script (complexity checker).

Make sure you've installed the flake8 package.

If you use vim >= 8, install this plugin with:

mkdir -p ~/.vim/pack/flake8/start/
cd ~/.vim/pack/flake8/start/
git clone https://github.com/nvie/vim-flake8.git

Otherwise, install vim-pathogen if you're not using it already. Then, simply put the contents of this repository in your ~/.vim/bundle directory.

1. Open a Python file
2. Press <F7> to run flake8 on it

It shows the errors inside a quickfix window, which will allow your to quickly jump to the error locations by simply pressing [Enter].

If any of g:flake8_show_in_gutter or g:flake8_show_in_file are set to 1, call:

call flake8#Flake8UnplaceMarkers()

To remove all markers. No default mapping is provided.

If you don't want to use the <F7> key for flake8-checking, simply remap it to another key. It autodetects whether it has been remapped and won't register the <F7> key if so. For example, to remap it to <F3> instead, use:

autocmd FileType python map <buffer> <F3> :call flake8#Flake8()<CR>

For flake8 configuration options please consult the following page:

http://flake8.pycqa.org/en/latest/user/configuration.html

To customize the location of your flake8 binary, set g:flake8_cmd:

let g:flake8_cmd="/opt/strangebin/flake8000"

To customize the location of quick fix window, set g:flake8_quickfix_location:

let g:flake8_quickfix_location="topleft"

To customize the height of quick fix window, set g:flake8_quickfix_height:

let g:flake8_quickfix_height=7

To customize whether the quickfix window opens, set g:flake8_show_quickfix:

let g:flake8_show_quickfix=0  " don't show
let g:flake8_show_quickfix=1  " show (default)

To customize whether the show signs in the gutter, set g:flake8_show_in_gutter:

let g:flake8_show_in_gutter=0  " don't show (default)
let g:flake8_show_in_gutter=1  " show

To customize whether the show marks in the file, set g:flake8_show_in_file:

let g:flake8_show_in_file=0  " don't show (default)
let g:flake8_show_in_file=1  " show

To customize the number of marks to show, set g:flake8_max_markers:

let g:flake8_max_markers=500  " (default)

To customize the gutter markers, set any of flake8_error_marker, flake8_warning_marker, flake8_pyflake_marker, flake8_complexity_marker, flake8_naming_marker. Setting one to the empty string disables it. Ex.:

flake8_error_marker='EE'     " set error marker to 'EE'
flake8_warning_marker='WW'   " set warning marker to 'WW'
flake8_pyflake_marker=''     " disable PyFlakes warnings
flake8_complexity_marker=''  " disable McCabe complexity warnings
flake8_naming_marker=''      " disable naming warnings

To customize the colors used for markers, define the highlight groups, Flake8_Error, Flake8_Warning, Flake8_PyFlake, Flake8_Complexity, Flake8_Naming:

" to use colors defined in the colorscheme
highlight link Flake8_Error      Error
highlight link Flake8_Warning    WarningMsg
highlight link Flake8_Complexity WarningMsg
highlight link Flake8_Naming     WarningMsg
highlight link Flake8_PyFlake    WarningMsg

A tip might be to run the Flake8 check every time you write a Python file, to enable this, add the following line to your .vimrc file (thanks Godefroid!):

autocmd BufWritePost *.py call flake8#Flake8()

This plugin goes well together with the following plugin:

• PyUnit (unit test helper under <F8> and <F9>)

One particular customization a lot of people like to make is relaxing the maximum line length default. This is a config setting that should be set in flake8 itself. (vim-flake8 "just" invokes it and deals with showing the output in Vim's quickfix window.)

To do so, put the following into your ~/.config/flake8 file:

[flake8]
max-line-length = 120

1.6: Deprecated configuring flake8 options through Vim settings. Instead, advise users to use the ~/.config/flake8 config file.

- Decprecated options:
  - `g:flake8_builtins`
  - `g:flake8_ignore`
  - `g:flake8_max_line_length`
  - `g:flake8_max_complexity`

- New options:
  - `g:flake8_quickfix_height`

1.5: Added markers and the option to don't show the quickfix window, also split functions into a autoload file. Added:

- Options:
  - `g:flake8_show_quickfix`
  - `g:flake8_show_in_gutter`
  - `g:flake8_show_in_file`
  - `g:flake8_max_markers`
  - `flake8_error_marker`
  - `flake8_warning_marker`
  - `flake8_pyflake_marker`
  - `flake8_complexity_marker`
  - `flake8_naming_marker`
- Functions:
  - `flake8#Flake8UnplaceMarkers()`
  - `flake8#Flake8()`
- Highlighting:
  - `Flake8_Error`
  - `Flake8_Warning`
  - `Flake8_Complexity`
  - `Flake8_Naming`
  - `Flake8_PyFlake`

1.4: Suppress output to stdout.

1.3: Added the following options:

- `g:flake8_builtins="_,apply"`
- `g:flake8_max_complexity=10`

1.2: Added the following options:

- `g:flake8_cmd="/opt/strangebin/flake8000"`
- `g:flake8_max_line_length=120`
- `g:flake8_ignore="E501,W293"`

1.1: Added g:flake8_ignore option.

1.0: Initial version.

Liberally licensed under BSD terms.