Add an option to save hidden buffers

When commands are run, it can be useful to just save the hidden buffers
so language servers immediately get updated with changes to files
without you having to manually save each file. You can now enable this
by setting `g:ale_save_hidden` to `1`.

autoload/ale/organize_imports.vim

@@ -19,7 +19,7 @@ function! ale#organize_imports#HandleTSServerResponse(conn_id, response) abort
     \   },
     \   {
     \       'conn_id': a:conn_id,
-    \       'should_save': !&hidden,
+    \       'should_save': g:ale_save_hidden || !&hidden,
     \   },
     \)
 endfunction

autoload/ale/rename.vim

@@ -85,7 +85,7 @@ function! ale#rename#HandleTSServerResponse(conn_id, response) abort
     \   },
     \   {
     \       'conn_id': a:conn_id,
-    \       'should_save': !&hidden,
+    \       'should_save': g:ale_save_hidden || !&hidden,
     \   },
     \)
 endfunction
@@ -118,7 +118,7 @@ function! ale#rename#HandleLSPResponse(conn_id, response) abort
         \   },
         \   {
         \       'conn_id': a:conn_id,
-        \       'should_save': !&hidden,
+        \       'should_save': g:ale_save_hidden || !&hidden,
         \   },
         \)
     endif

doc/ale.txt

@@ -1260,7 +1260,6 @@ g:ale_floating_preview_popup_opts           *g:ale_floating_preview_popup_opts*
   let g:ale_floating_preview_popup_opts = 'g:CustomOpts'
 <
 
-
 g:ale_floating_window_border                     *g:ale_floating_window_border*
 
   Type: |List|
@@ -1974,6 +1973,16 @@ g:ale_root                                                         *g:ale_root*
   LSP linter, it will not run.
 
 
+g:ale_save_hidden                                           *g:ale_save_hidden*
+
+  Type: |Number|
+  Default: `0`
+
+  When set to `1`, save buffers when 'hidden' is set when applying code
+  actions or rename operations, such as through |ALERename| or
+  |ALEOrganizeImports|.
+
+
 g:ale_set_balloons                                         *g:ale_set_balloons*
                                                            *b:ale_set_balloons*
 
@@ -3646,14 +3655,15 @@ ALERename                                                           *ALERename*
   The symbol where the cursor is resting will be the symbol renamed, and a
   prompt will open to request a new name.
 
-  The rename operation will save all modified buffers when `set nohidden` is
-  set, because that disables leaving unsaved buffers in the background. See
-  `:help hidden` for more details.
+  The rename operation will not save modified buffers when 'hidden' is on
+  unless |g:ale_save_hidden| is `1`.
+
 
 ALEFileRename                                                   *ALEFileRename*
 
   Rename a file and fix imports using `tsserver`.
 
+
 ALECodeAction                                                   *ALECodeAction*
 
   Apply a code action via LSP servers or `tsserver`.

plugin/ale.vim

@@ -191,6 +191,9 @@ let g:ale_deno_executable = get(g:, 'ale_deno_executable', 'deno')
 " If 1, enable a popup menu for commands.
 let g:ale_popup_menu_enabled = get(g:, 'ale_popup_menu_enabled', has('gui_running'))
 
+" If 0, save hidden files when code actions are applied.
+let g:ale_save_hidden = get(g:, 'ale_save_hidden', 0)
+
 " If 1, disables ALE's built in error display. Instead, all errors are piped
 " to the diagnostics API.
 let g:ale_use_neovim_diagnostics_api = get(g:, 'ale_use_neovim_diagnostics_api', 0)

test/test_organize_imports.vader

@@ -59,7 +59,7 @@ Before:
 
   function! ale#code_action#HandleCodeAction(code_action, options) abort
     let g:handle_code_action_called = 1
-    AssertEqual !&hidden, get(a:options, 'should_save')
+    AssertEqual g:ale_save_hidden || !&hidden, get(a:options, 'should_save')
     call add(g:code_actions, a:code_action)
   endfunction
 

test/test_rename.vader

@@ -59,7 +59,7 @@ Before:
 
   function! ale#code_action#HandleCodeAction(code_action, options) abort
     let g:handle_code_action_called = 1
-    AssertEqual !&hidden, get(a:options, 'should_save', 0)
+    AssertEqual g:ale_save_hidden || !&hidden, get(a:options, 'should_save', 0)
     call add(g:code_actions, a:code_action)
   endfunction