#3319 - Try to modify buffers later for ALEFix

3 files changed, 32 insertions, 23 deletions

diff --git a/autoload/ale/fix.vim b/autoload/ale/fix.vim
index 3ad0a433..b04ab18f 100644
--- a/autoload/ale/fix.vim
+++ b/autoload/ale/fix.vim
@@ -15,22 +15,29 @@ function! ale#fix#ApplyQueuedFixes(buffer) abort
 
     call remove(g:ale_fix_buffer_data, a:buffer)
 
-    if l:data.changes_made
-        let l:new_lines = ale#util#SetBufferContents(a:buffer, l:data.output)
-
-        if l:data.should_save
-            if a:buffer is bufnr('')
-                if empty(&buftype)
-                    noautocmd :w!
+    try
+        if l:data.changes_made
+            let l:new_lines = ale#util#SetBufferContents(a:buffer, l:data.output)
+
+            if l:data.should_save
+                if a:buffer is bufnr('')
+                    if empty(&buftype)
+                        noautocmd :w!
+                    else
+                        set nomodified
+                    endif
                 else
-                    set nomodified
+                    call writefile(l:new_lines, expand('#' . a:buffer . ':p')) " no-custom-checks
+                    call setbufvar(a:buffer, '&modified', 0)
                 endif
-            else
-                call writefile(l:new_lines, expand('#' . a:buffer . ':p')) " no-custom-checks
-                call setbufvar(a:buffer, '&modified', 0)
             endif
         endif
-    endif
+    catch /E21/
+        " If we cannot modify the buffer now, try again later.
+        let g:ale_fix_buffer_data[a:buffer] = l:data
+
+        return
+    endtry
 
     if l:data.should_save
         let l:should_lint = ale#Var(a:buffer, 'fix_on_save')
diff --git a/autoload/ale/util.vim b/autoload/ale/util.vim
index 05f11993..1f396377 100644
--- a/autoload/ale/util.vim
+++ b/autoload/ale/util.vim
@@ -505,13 +505,6 @@ function! ale#util#SetBufferContents(buffer, lines) abort
     \   : a:lines
     let l:first_line_to_remove = len(l:new_lines) + 1
 
-    " We'll temporarily make a buffer modifiable, to force edits.
-    let l:modifiable = getbufvar(a:buffer, '&modifiable')
-
-    if !l:modifiable
-        call setbufvar(a:buffer, '&modifiable', 1)
-    endif
-
     " Use a Vim API for setting lines in other buffers, if available.
     if l:has_bufline_api
         call setbufline(a:buffer, 1, l:new_lines)
@@ -530,9 +523,5 @@ function! ale#util#SetBufferContents(buffer, lines) abort
         call setline(1, l:new_lines)
     endif
 
-    if !l:modifiable
-        call setbufvar(a:buffer, '&modifiable', 0)
-    endif
-
     return l:new_lines
 endfunction
diff --git a/test/fix/test_ale_fix.vader b/test/fix/test_ale_fix.vader
index e8a9dd7a..62643da2 100644
--- a/test/fix/test_ale_fix.vader
+++ b/test/fix/test_ale_fix.vader
@@ -727,6 +727,19 @@ Expect(There should be only two lines):
   a
   b
 
+Execute(ALEFix should modify a buffer that is not modifiable, if it becomes modifable later):
+  let g:ale_fixers.testft = ['RemoveLastLineOneArg']
+
+  set nomodifiable
+  ALEFix
+  call ale#test#FlushJobs()
+  set modifiable
+  call ale#fix#ApplyQueuedFixes(bufnr(''))
+
+Expect(There should be only two lines):
+  a
+  b
+
 Execute(b:ale_fix_on_save = 1 should override g:ale_fix_on_save = 0):
   let g:ale_fix_on_save = 0
   let b:ale_fix_on_save = 1