add: support for ruff as a Python linter and fixer (#4347)

this commit adds ruff as both a Python linter and fixer, together with
some tests and documentation.

ruff repo: https://github.com/charliermarsh/ruff

1 files changed, 84 insertions, 0 deletions

diff --git a/ale_linters/python/ruff.vim b/ale_linters/python/ruff.vim
new file mode 100644
index 00000000..67595fe3
--- /dev/null
+++ b/ale_linters/python/ruff.vim
@@ -0,0 +1,84 @@
+" Author: Yining <zhang.yining@gmail.com>
+" Description: ruff as linter for python files
+
+call ale#Set('python_ruff_executable', 'ruff')
+call ale#Set('python_ruff_options', '')
+call ale#Set('python_ruff_use_global', get(g:, 'ale_use_global_executables', 0))
+call ale#Set('python_ruff_change_directory', 1)
+call ale#Set('python_ruff_auto_pipenv', 0)
+call ale#Set('python_ruff_auto_poetry', 0)
+
+call ale#fix#registry#Add('ruff',
+\   'ale#fixers#ruff#Fix',
+\   ['python'],
+\   'A python linter/fixer for Python written in Rust'
+\)
+
+function! ale_linters#python#ruff#GetExecutable(buffer) abort
+    if (ale#Var(a:buffer, 'python_auto_pipenv') || ale#Var(a:buffer, 'python_ruff_auto_pipenv'))
+    \ && ale#python#PipenvPresent(a:buffer)
+        return 'pipenv'
+    endif
+
+    if (ale#Var(a:buffer, 'python_auto_poetry') || ale#Var(a:buffer, 'python_ruff_auto_poetry'))
+    \ && ale#python#PoetryPresent(a:buffer)
+        return 'poetry'
+    endif
+
+    return ale#python#FindExecutable(a:buffer, 'python_ruff', ['ruff'])
+endfunction
+
+function! ale_linters#python#ruff#GetCwd(buffer) abort
+    if ale#Var(a:buffer, 'python_ruff_change_directory')
+        " Run from project root if found, else from buffer dir.
+        let l:project_root = ale#python#FindProjectRoot(a:buffer)
+
+        return !empty(l:project_root) ? l:project_root : '%s:h'
+    endif
+
+    return ''
+endfunction
+
+function! ale_linters#python#ruff#GetCommand(buffer, version) abort
+    let l:executable = ale_linters#python#ruff#GetExecutable(a:buffer)
+    let l:exec_args = l:executable =~? 'pipenv\|poetry$'
+    \   ? ' run ruff'
+    \   : ''
+
+    " NOTE: ruff version `0.0.69` supports liniting input from stdin
+    return ale#Escape(l:executable) . l:exec_args
+    \   . ale#Pad(ale#Var(a:buffer, 'python_ruff_options'))
+    \   . ' --format text'
+    \   .  (ale#semver#GTE(a:version, [0, 0, 69]) ? ' -' : ' %s')
+endfunction
+
+function! ale_linters#python#ruff#Handle(buffer, lines) abort
+    "Example: path/to/file.py:10:5: E999 SyntaxError: unexpected indent
+    let l:pattern = '\v^[a-zA-Z]?:?[^:]+:(\d+):(\d+)?:? (.+)$'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        call add(l:output, {
+        \   'lnum': l:match[1] + 0,
+        \   'col': l:match[2] + 0,
+        \   'text': l:match[3],
+        \})
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('python', {
+\   'name': 'ruff',
+\   'executable': function('ale_linters#python#ruff#GetExecutable'),
+\   'cwd': function('ale_linters#python#ruff#GetCwd'),
+\   'command': {buffer -> ale#semver#RunWithVersionCheck(
+\       buffer,
+\       ale_linters#python#ruff#GetExecutable(buffer),
+\       '%e --version',
+\       function('ale_linters#python#ruff#GetCommand'),
+\   )},
+\   'callback': 'ale_linters#python#ruff#Handle',
+\   'output_stream': 'both',
+\   'read_buffer': 1,
+\})