add unimport fixer (#5068)

autoload/ale/fix/registry.vim

@@ -192,6 +192,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['python'],
 \       'description': 'Tidy Python imports with pyflyby.',
 \   },
+\   'unimport': {
+\       'function': 'ale#fixers#unimport#Fix',
+\       'suggested_filetypes': ['python'],
+\       'description': 'unimport fixer',
+\   },
 \   'importjs': {
 \       'function': 'ale#fixers#importjs#Fix',
 \       'suggested_filetypes': ['javascript'],

autoload/ale/fixers/unimport.vim

@@ -0,0 +1,42 @@
+call ale#Set('python_unimport_executable', 'unimport')
+call ale#Set('python_unimport_use_global', get(g:, 'ale_use_global_executables', 0))
+call ale#Set('python_unimport_options', '')
+call ale#Set('python_unimport_auto_pipenv', 0)
+call ale#Set('python_unimport_auto_poetry', 0)
+call ale#Set('python_unimport_auto_uv', 0)
+
+function! ale#fixers#unimport#GetExecutable(buffer) abort
+    if (ale#Var(a:buffer, 'python_auto_pipenv') || ale#Var(a:buffer, 'python_unimport_auto_pipenv'))
+    \ && ale#python#PipenvPresent(a:buffer)
+        return 'pipenv'
+    endif
+
+    if (ale#Var(a:buffer, 'python_auto_poetry') || ale#Var(a:buffer, 'python_unimport_auto_poetry'))
+    \ && ale#python#PoetryPresent(a:buffer)
+        return 'poetry'
+    endif
+
+    if (ale#Var(a:buffer, 'python_auto_uv') || ale#Var(a:buffer, 'python_unimport_auto_uv'))
+    \ && ale#python#UvPresent(a:buffer)
+        return 'uv'
+    endif
+
+    return ale#python#FindExecutable(a:buffer, 'python_unimport', ['unimport'])
+endfunction
+
+function! ale#fixers#unimport#Fix(buffer) abort
+    let l:executable = ale#fixers#unimport#GetExecutable(a:buffer)
+    let l:cmd = [ale#Escape(l:executable)]
+
+    if l:executable =~? '\(pipenv\|poetry\|uv\)$'
+        call extend(l:cmd, ['run', 'unimport'])
+    endif
+
+    let l:options = ale#Var(a:buffer, 'python_unimport_options')
+
+    if !empty(l:options)
+        call add(l:cmd, l:options)
+    endif
+
+    return {'command': join(l:cmd, ' ')}
+endfunction