#1700 - Don't send <C-x><C-o> for completion in Insert mode

autoload/ale/completion.vim

@@ -1,6 +1,17 @@
 " Author: w0rp <devw0rp@gmail.com>
 " Description: Completion support for LSP linters
 
+" The omnicompletion menu is shown through a special Plug mapping which is
+" only valid in Insert mode. This way, feedkeys() won't send these keys if you
+" quit Insert mode quickly enough.
+inoremap <silent> <Plug>(ale_show_completion_menu) <C-x><C-o>
+" If we hit the key sequence in normal mode, then we won't show the menu, so
+" we should restore the old settings right away.
+nnoremap <silent> <Plug>(ale_show_completion_menu) :call ale#completion#RestoreCompletionOptions()<CR>
+cnoremap <silent> <Plug>(ale_show_completion_menu) <Nop>
+vnoremap <silent> <Plug>(ale_show_completion_menu) <Nop>
+onoremap <silent> <Plug>(ale_show_completion_menu) <Nop>
+
 let g:ale_completion_delay = get(g:, 'ale_completion_delay', 100)
 let g:ale_completion_excluded_words = get(g:, 'ale_completion_excluded_words', [])
 let g:ale_completion_max_suggestions = get(g:, 'ale_completion_max_suggestions', 50)
@@ -129,7 +140,16 @@ function! ale#completion#Filter(buffer, suggestions, prefix) abort
     return l:filtered_suggestions
 endfunction
 
-function! s:ReplaceCompleteopt() abort
+function! s:ReplaceCompletionOptions() abort
+    " Remember the old omnifunc value, if there is one.
+    " If we don't store an old one, we'll just never reset the option.
+    " This will stop some random exceptions from appearing.
+    if !exists('b:ale_old_omnifunc') && !empty(&l:omnifunc)
+        let b:ale_old_omnifunc = &l:omnifunc
+    endif
+
+    let &l:omnifunc = 'ale#completion#OmniFunc'
+
     if !exists('b:ale_old_completopt')
         let b:ale_old_completopt = &l:completeopt
     endif
@@ -141,6 +161,22 @@ function! s:ReplaceCompleteopt() abort
     endif
 endfunction
 
+function! ale#completion#RestoreCompletionOptions() abort
+    " Reset settings when completion is done.
+    if exists('b:ale_old_omnifunc')
+        if b:ale_old_omnifunc isnot# 'pythoncomplete#Complete'
+            let &l:omnifunc = b:ale_old_omnifunc
+        endif
+
+        unlet b:ale_old_omnifunc
+    endif
+
+    if exists('b:ale_old_completopt')
+        let &l:completeopt = b:ale_old_completopt
+        unlet b:ale_old_completopt
+    endif
+endfunction
+
 function! ale#completion#OmniFunc(findstart, base) abort
     if a:findstart
         let l:line = b:ale_completion_info.line
@@ -163,7 +199,7 @@ function! ale#completion#OmniFunc(findstart, base) abort
             let b:ale_completion_result = function(l:parser)(l:response)
         endif
 
-        call s:ReplaceCompleteopt()
+        call s:ReplaceCompletionOptions()
 
         return get(b:, 'ale_completion_result', [])
     endif
@@ -174,20 +210,12 @@ function! ale#completion#Show(response, completion_parser) abort
         return
     endif
 
-    " Remember the old omnifunc value, if there is one.
-    " If we don't store an old one, we'll just never reset the option.
-    " This will stop some random exceptions from appearing.
-    if !exists('b:ale_old_omnifunc') && !empty(&l:omnifunc)
-        let b:ale_old_omnifunc = &l:omnifunc
-    endif
-
     " Set the list in the buffer, temporarily replace omnifunc with our
     " function, and then start omni-completion.
     let b:ale_completion_response = a:response
     let b:ale_completion_parser = a:completion_parser
-    let &l:omnifunc = 'ale#completion#OmniFunc'
+    call s:ReplaceCompletionOptions()
-    call s:ReplaceCompleteopt()
+    call ale#util#FeedKeys("\<Plug>(ale_show_completion_menu)")
-    call ale#util#FeedKeys("\<C-x>\<C-o>", 'n')
 endfunction
 
 function! s:CompletionStillValid(request_id) abort
@@ -523,19 +551,7 @@ endfunction
 function! ale#completion#Done() abort
     silent! pclose
 
-    " Reset settings when completion is done.
+    call ale#completion#RestoreCompletionOptions()
-    if exists('b:ale_old_omnifunc')
-        if b:ale_old_omnifunc isnot# 'pythoncomplete#Complete'
-            let &l:omnifunc = b:ale_old_omnifunc
-        endif
-
-        unlet b:ale_old_omnifunc
-    endif
-
-    if exists('b:ale_old_completopt')
-        let &l:completeopt = b:ale_old_completopt
-        unlet b:ale_old_completopt
-    endif
 
     let s:last_done_pos = getcurpos()[1:2]
 endfunction

test/completion/test_completion_events.vader

@@ -14,8 +14,8 @@ Before:
 
   runtime autoload/ale/util.vim
 
-  function! ale#util#FeedKeys(string, mode) abort
+  function! ale#util#FeedKeys(string) abort
-    call add(g:feedkeys_calls, [a:string, a:mode])
+    call add(g:feedkeys_calls, [a:string])
   endfunction
 
   " Pretend we're in insert mode for most tests.
@@ -41,6 +41,7 @@ Before:
 After:
   Restore
 
+  unlet! g:output
   unlet! g:fake_mode
   unlet! g:get_completions_called
   unlet! b:ale_old_omnifunc
@@ -155,7 +156,7 @@ Execute(ale#completion#OmniFunc() should set the preview option if it's set):
 Execute(ale#completion#Show() should make the correct feedkeys() call):
   call ale#completion#Show('Response', 'Parser')
 
-  AssertEqual [["\<C-x>\<C-o>", 'n']], g:feedkeys_calls
+  AssertEqual [["\<Plug>(ale_show_completion_menu)"]], g:feedkeys_calls
 
 Execute(ale#completion#Show() shouldn't do anything if you switch back to normal mode):
   let &l:completeopt = 'menu,preview'
@@ -225,3 +226,28 @@ Execute(b:ale_completion_info should be set up correctly when requesting complet
   \   'prefix': 'ab',
   \ },
   \ b:ale_completion_info
+
+Execute(The correct keybinds should be configured):
+  redir => g:output
+    silent map <Plug>(ale_show_completion_menu)
+  redir END
+
+  AssertEqual
+  \ [
+  \   'n  <Plug>(ale_show_completion_menu) * :call ale#completion#RestoreCompletionOptions()<CR>',
+  \   'o  <Plug>(ale_show_completion_menu) * <Nop>',
+  \   'v  <Plug>(ale_show_completion_menu) * <Nop>',
+  \ ],
+  \ sort(split(g:output, "\n"))
+
+Execute(Running the normal mode <Plug> keybind should reset the settings):
+  let b:ale_old_omnifunc = 'FooBar'
+  let b:ale_old_completopt = 'menu'
+
+  " We can't run the keybind, but we can call the function.
+  call ale#completion#RestoreCompletionOptions()
+
+  AssertEqual 'FooBar', &l:omnifunc
+  AssertEqual 'menu', &l:completeopt
+  Assert !has_key(b:, 'ale_old_omnifunc')
+  Assert !has_key(b:, 'ale_old_completopt')