Add golangci-lint fixer (#4853)

Closes #4616

autoload/ale/fix/registry.vim

@@ -327,6 +327,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['go'],
 \       'description': 'Fix Go files imports with goimports.',
 \   },
+\   'golangci_lint': {
+\       'function': 'ale#fixers#golangci_lint#Fix',
+\       'suggested_filetypes': ['go'],
+\       'description': 'Fix Go files with golangci-lint.',
+\   },
 \   'golines': {
 \       'function': 'ale#fixers#golines#Fix',
 \       'suggested_filetypes': ['go'],

autoload/ale/fixers/golangci_lint.vim

@@ -0,0 +1,32 @@
+" Author: Ian Stapleton Cordasco <graffatcolmingov@gmail.com>
+" Description: Run golangci-lint with the --fix flag to autofix some issues
+
+call ale#Set('go_golangci_lint_options', '')
+call ale#Set('go_golangci_lint_executable', 'golangci-lint')
+call ale#Set('go_golangci_lint_package', 1)
+
+function! ale#fixers#golangci_lint#GetCommand(buffer) abort
+    let l:filename = expand('#' . a:buffer . ':t')
+    let l:executable = ale#Var(a:buffer, 'go_golangci_lint_executable')
+    let l:options = ale#Var(a:buffer, 'go_golangci_lint_options') . ' --fix'
+    let l:package_mode = ale#Var(a:buffer, 'go_golangci_lint_package')
+    let l:env = ale#go#EnvString(a:buffer)
+
+
+    if l:package_mode
+        return l:env . ale#Escape(l:executable)
+        \   . ' run '
+        \   .  l:options
+    endif
+
+    return l:env . ale#Escape(l:executable)
+    \   . ' run '
+    \   . l:options
+    \   . ' ' . ale#Escape(l:filename)
+endfunction
+
+function! ale#fixers#golangci_lint#Fix(buffer) abort
+    return {
+    \  'command': ale#fixers#golangci_lint#GetCommand(a:buffer),
+    \}
+endfunction

test/fixers/test_golangci_lint_fixer_callback.vader

@@ -0,0 +1,48 @@
+Before:
+  Save g:ale_go_go111module
+  Save g:ale_go_golangci_lint_executable
+  Save g:ale_go_golangci_lint_options
+  Save g:ale_go_golangci_lint_package
+
+  " Use an invalid global executable, so we don't match it.
+  let g:ale_go_golangci_lint_executable = 'xxxinvalid'
+  let g:ale_go_golangci_lint_options = ''
+
+  call ale#test#SetDirectory('/testplugin/test/fixers')
+  call ale#test#SetFilename('../test-files/go/testfile.go')
+After:
+  Restore
+
+  unlet! b:ale_go_go111module
+
+  call ale#test#RestoreDirectory()
+
+Execute(The golangci-lint callback should return the correct default values):
+
+  AssertEqual
+  \ {
+  \   'command': ale#Escape('xxxinvalid') . ' run  --fix',
+  \ },
+  \ ale#fixers#golangci_lint#Fix(bufnr(''))
+
+Execute(The golangci-lint callback should include custom golangci-lint options):
+  let g:ale_go_golangci_lint_options = "--new --config /dev/null"
+
+  AssertEqual
+  \ {
+  \   'command': ale#Escape('xxxinvalid')
+  \     . ' run ' . g:ale_go_golangci_lint_options . ' --fix',
+  \ },
+  \ ale#fixers#golangci_lint#Fix(bufnr(''))
+
+Execute(The golangci-lint callback should support per-file mode):
+  let g:ale_go_golangci_lint_package = 0
+
+  AssertEqual
+  \ {
+  \   'command': ale#Escape('xxxinvalid')
+  \     . ' run '
+  \     . g:ale_go_golangci_lint_options
+  \     . ' --fix ' . ale#Escape('testfile.go'),
+  \ },
+  \ ale#fixers#golangci_lint#Fix(bufnr(''))