#653 Set loclists better when taking data from previous buffers

autoload/ale/engine.vim

@@ -728,7 +728,10 @@ function! s:AddProblemsFromOtherBuffers(buffer, linters) abort
             if has_key(l:item, 'filename')
             \&& l:item.filename is# l:filename
             \&& has_key(l:name_map, l:item.linter_name)
-                call add(l:loclist, l:item)
+                " Copy the items and set the buffer numbers to this one.
+                let l:new_item = copy(l:item)
+                let l:new_item.bufnr = a:buffer
+                call add(l:loclist, l:new_item)
             endif
         endfor
     endfor
@@ -737,6 +740,8 @@ function! s:AddProblemsFromOtherBuffers(buffer, linters) abort
         call sort(l:loclist, function('ale#util#LocItemCompareWithText'))
         call uniq(l:loclist, function('ale#util#LocItemCompareWithText'))
 
+        " Set the loclist variable, used by some parts of ALE.
+        let g:ale_buffer_info[a:buffer].loclist = l:loclist
         call ale#engine#SetResults(a:buffer, l:loclist)
     endif
 endfunction

test/test_setting_problems_found_in_previous_buffers.vader

@@ -1,6 +1,9 @@
 Before:
   Save g:ale_buffer_info
   Save &filetype
+  Save g:ale_set_lists_synchronously
+
+  let g:ale_set_lists_synchronously = 1
 
   " Set up items in other buffers which should set in this one.
   let g:ale_buffer_info = {}
@@ -13,7 +16,7 @@ Before:
   \ ])
   call ale#engine#InitBufferInfo(bufnr('') + 2)
   let g:ale_buffer_info[bufnr('') + 2].loclist =
-  \ ale#engine#FixLocList(bufnr('') + 2, 'linter_two', [
+  \ ale#engine#FixLocList(bufnr('') + 2, 'linter_one', [
   \   {'lnum': 1, 'filename': expand('%:p'), 'text': 'foo'},
   \   {'lnum': 3, 'filename': expand('%:p'), 'text': 'baz'},
   \   {'lnum': 5, 'text': 'ignore this one'},
@@ -23,15 +26,9 @@ Before:
   \ 'name': 'linter_one',
   \ 'callback': 'WhoCares',
   \ 'executable': 'echo',
-  \ 'command': 'echo',
+  \ 'command': 'sleep 1000',
   \ 'lint_file': 1,
   \})
-  call ale#linter#Define('foobar', {
-  \ 'name': 'linter_two',
-  \ 'callback': 'WhoCares',
-  \ 'executable': 'echo',
-  \ 'command': 'echo',
-  \})
 
 After:
   call ale#engine#Cleanup(bufnr(''))
@@ -51,6 +48,47 @@ Given foobar(A file with some lines):
 Execute(Problems found from previously opened buffers should be set when linting for the first time):
   call ale#engine#RunLinters(bufnr(''), ale#linter#Get(&filetype), 0)
 
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 1,
+  \     'bufnr': bufnr(''),
+  \     'col': 0,
+  \     'filename': expand('%:p'),
+  \     'linter_name': 'linter_one',
+  \     'nr': -1,
+  \     'type': 'E',
+  \     'vcol': 0,
+  \     'text': 'foo',
+  \     'sign_id': 1000001,
+  \   },
+  \   {
+  \     'lnum': 2,
+  \     'bufnr': bufnr(''),
+  \     'col': 0,
+  \     'filename': expand('%:p'),
+  \     'linter_name': 'linter_one',
+  \     'nr': -1,
+  \     'type': 'E',
+  \     'vcol': 0,
+  \     'text': 'bar',
+  \     'sign_id': 1000002,
+  \   },
+  \   {
+  \     'lnum': 3,
+  \     'bufnr': bufnr(''),
+  \     'col': 0,
+  \     'filename': expand('%:p'),
+  \     'linter_name': 'linter_one',
+  \     'nr': -1,
+  \     'type': 'E',
+  \     'vcol': 0,
+  \     'text': 'baz',
+  \     'sign_id': 1000003,
+  \   },
+  \ ],
+  \ g:ale_buffer_info[bufnr('')].loclist
+
   AssertEqual
   \ [
   \   {'lnum': 1, 'bufnr': bufnr(''), 'col': 0, 'valid': 1, 'vcol': 0, 'nr': -1, 'type': 'E', 'pattern': '', 'text': 'foo'},