Fix cwd setting to use .stylua.toml if stylua.toml is not found (#4892)

autoload/ale/fixers/stylua.vim

@@ -8,10 +8,12 @@ function! ale#fixers#stylua#GetCwd(buffer) abort
     for l:possible_configfile in ['stylua.toml', '.stylua.toml']
         let l:config = ale#path#FindNearestFile(a:buffer, l:possible_configfile)
 
-        return !empty(l:config) ? fnamemodify(l:config, ':h') : '%s:h'
+        if !empty(l:config)
+            return fnamemodify(l:config, ':h')
+        endif
     endfor
 
-    return ''
+    return '%s:h'
 endfunction
 
 function! ale#fixers#stylua#Fix(buffer) abort

test/fixers/test_stylua_fixer_callback.vader

@@ -18,3 +18,21 @@ Execute(The stylua callback should include custom stylua options):
   \     . ' ' . g:ale_lua_stylua_options
   \     . ' --stdin-filepath %s -',
   \ }
+
+Execute(stylua should detect stylua.toml):
+  call ale#test#SetFilename('../test-files/stylua/stylua_config_dir/subdir/test.lua')
+
+  AssertFixer
+  \ {
+  \   'cwd': ale#path#Simplify(g:dir . '/../test-files/stylua/stylua_config_dir'),
+  \   'command': ale#Escape('stylua') . ' --stdin-filepath %s -',
+  \ }
+
+Execute(stylua should detect .stylua.toml):
+  call ale#test#SetFilename('../test-files/stylua/stylua_dot_config_dir/subdir/test.lua')
+
+  AssertFixer
+  \ {
+  \   'cwd': ale#path#Simplify(g:dir . '/../test-files/stylua/stylua_dot_config_dir'),
+  \   'command': ale#Escape('stylua') . ' --stdin-filepath %s -',
+  \ }