From ebbbeacfdb5c68b7bcce824280aa4c24943eebe5 Mon Sep 17 00:00:00 2001
From: Andrey Popp <8mayday@gmail.com>
Date: Sun, 12 May 2019 12:55:44 +0300
Subject: [PATCH] Lint on FocusGained/VimResume

This commits allow to configure ALE to lint when vim gains focus or is
resumed after being suspended (C-z and then `fg` command).

Not that for this to work with tmux one must set
```
set -g focus-events on
```
in their `tmux.conf`.
---
 autoload/ale/events.vim | 18 ++++++++++++++++++
 autoload/ale/lsp.vim    |  4 +++-
 plugin/ale.vim          |  3 +++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/autoload/ale/events.vim b/autoload/ale/events.vim
index c3dbd37890..1f0864bc0e 100644
--- a/autoload/ale/events.vim
+++ b/autoload/ale/events.vim
@@ -92,6 +92,11 @@ function! ale#events#FileChangedEvent(buffer) abort
     endif
 endfunction
 
+function! ale#events#FocusGained(buffer) abort
+    call setbufvar(a:buffer, 'force_changedtick', 1)
+    call ale#Queue(0, 'lint_file', a:buffer)
+endfunction
+
 function! ale#events#Init() abort
     " This value used to be a Boolean as a Number, and is now a String.
     let l:text_changed = '' . g:ale_lint_on_text_changed
@@ -127,6 +132,19 @@ function! ale#events#Init() abort
                 \)
             endif
 
+            if g:ale_lint_on_focus_gained
+                if exists('##FocusGained')
+                    autocmd FocusGained * call ale#events#FocusGained(
+                    \   str2nr(expand('<abuf>'))
+                    \)
+                endif
+                if exists('##VimResume')
+                    autocmd VimResume * call ale#events#FocusGained(
+                    \   str2nr(expand('<abuf>'))
+                    \)
+                endif
+            endif
+
             if g:ale_lint_on_insert_leave
                 autocmd InsertLeave * call ale#Queue(0)
             endif
diff --git a/autoload/ale/lsp.vim b/autoload/ale/lsp.vim
index 7186d2a9d7..3fcc7b83f8 100644
--- a/autoload/ale/lsp.vim
+++ b/autoload/ale/lsp.vim
@@ -492,8 +492,10 @@ function! ale#lsp#NotifyForChanges(conn_id, buffer) abort
 
     if !empty(l:conn) && has_key(l:conn.open_documents, a:buffer)
         let l:new_tick = getbufvar(a:buffer, 'changedtick')
+        let l:force = getbufvar(a:buffer, 'force_changedtick', 0)
 
-        if l:conn.open_documents[a:buffer] < l:new_tick
+        if l:conn.open_documents[a:buffer] < l:new_tick || l:force
+            call setbufvar(a:buffer, 'force_changedtick', 0)
             if l:conn.is_tsserver
                 let l:message = ale#lsp#tsserver_message#Change(a:buffer)
             else
diff --git a/plugin/ale.vim b/plugin/ale.vim
index cf39d6328e..5372bbc962 100644
--- a/plugin/ale.vim
+++ b/plugin/ale.vim
@@ -87,6 +87,9 @@ let g:ale_lint_on_save = get(g:, 'ale_lint_on_save', 1)
 " This flag can be set to 1 to enable linting when the filetype is changed.
 let g:ale_lint_on_filetype_changed = get(g:, 'ale_lint_on_filetype_changed', 1)
 
+" This flag can be set to 1 to enable linting when vim gains focus.
+let g:ale_lint_on_focus_gained = get(g:, 'ale_lint_on_focus_gained', 1)
+
 " This Dictionary configures the default LSP roots for various linters.
 let g:ale_lsp_root = get(g:, 'ale_lsp_root', {})