Fix #1960 - Do not fix files on :wq

autoload/ale/events.vim

@@ -29,7 +29,7 @@ function! ale#events#SaveEvent(buffer) abort
         call setbufvar(a:buffer, 'ale_save_event_fired', 1)
     endif
 
-    if ale#Var(a:buffer, 'fix_on_save')
+    if ale#Var(a:buffer, 'fix_on_save') && !ale#events#QuitRecently(a:buffer)
         let l:will_fix = ale#fix#Fix(a:buffer, 'save_file')
         let l:should_lint = l:should_lint && !l:will_fix
     endif

doc/ale.txt

@@ -1186,6 +1186,9 @@ b:ale_fix_on_save                                           *b:ale_fix_on_save*
   after files are fixed, only when the buffer is open, or re-opened. Changes
   to the file will be saved to the file on disk.
 
+  Files will not be fixed on `:wq`, so you should check your code before
+  closing a buffer.
+
   Fixing files can be disabled or enabled for individual buffers by setting
   `b:ale_fix_on_save` to `0` or `1`.
 

test/fix/test_ale_fix.vader

@@ -180,6 +180,7 @@ After:
   unlet! g:ale_emulate_job_failure
   unlet! b:ale_fixers
   unlet! b:ale_fix_on_save
+  unlet! b:ale_quitting
   delfunction AddCarets
   delfunction AddDollars
   delfunction DoNothing
@@ -431,7 +432,7 @@ Given testft (A file with three lines):
   b
   c
 
-Execute(ALEFix should save files on the save event):
+Execute(ALEFix should fix files on the save event):
   let g:ale_fix_on_save = 1
   let g:ale_lint_on_save = 1
   let g:ale_enabled = 1
@@ -471,6 +472,36 @@ Expect(The buffer should be modified):
   $b
   $c
 
+Execute(ALEFix should not fix files on :wq):
+  let g:ale_fix_on_save = 1
+  let g:ale_lint_on_save = 1
+  let g:ale_enabled = 1
+
+  noautocmd silent file fix_test_file
+  call writefile(getline(1, '$'), 'fix_test_file')
+
+  let g:ale_fixers.testft = ['AddDollars']
+
+  " We have to set the buftype to empty so the file will be written.
+  setlocal buftype=
+
+  call ale#events#QuitEvent(bufnr(''))
+
+  call SetUpLinters()
+  call ale#events#SaveEvent(bufnr(''))
+
+  " We should save the file.
+  AssertEqual ['a', 'b', 'c'], readfile('fix_test_file')
+  Assert &modified, 'The was not marked as ''modified'''
+
+  " We should not run the linter.
+  AssertEqual [], ale#test#GetLoclistWithoutModule()
+
+Expect(The buffer should not be modified):
+  a
+  b
+  c
+
 Given testft (A file with three lines):
   a
   b