#734 - Do not clear file linter results when no buffers are run

autoload/ale/engine.vim

@@ -667,25 +667,26 @@ function! ale#engine#RunLinters(buffer, linters, should_lint_file) abort
     call s:StopCurrentJobs(a:buffer, a:should_lint_file)
     call s:RemoveProblemsForDisabledLinters(a:buffer, a:linters)
 
-    let l:any_linter_ran = 0
+    " We can only clear the results if we aren't checking the buffer.
+    let l:can_clear_results = !ale#engine#IsCheckingBuffer(a:buffer)
 
     for l:linter in a:linters
-        " Skip linters for checking files if we shouldn't check the file.
-        if l:linter.lint_file && !a:should_lint_file
-            continue
-        endif
-
+        " Only run lint_file linters if we should.
+        if !l:linter.lint_file || a:should_lint_file
             if s:RunLinter(a:buffer, l:linter)
-            let l:any_linter_ran = 1
+                " If a single linter ran, we shouldn't clear everything.
+                let l:can_clear_results = 0
+            endif
+        else
+            " If we skipped running a lint_file linter still in the list,
+            " we shouldn't clear everything.
+            let l:can_clear_results = 0
         endif
     endfor
 
-    " If we didn't manage to start checking the buffer with anything,
-    " and there's nothing running currently for the buffer, then clear the
-    " results.
-    "
-    " We need to use both checks, as we run some tests synchronously.
-    if !l:any_linter_ran && !ale#engine#IsCheckingBuffer(a:buffer)
+    " Clear the results if we can. This needs to be done when linters are
+    " disabled, or ALE itself is disabled.
+    if l:can_clear_results
         call ale#engine#SetResults(a:buffer, [])
     endif
 endfunction

test/test_lint_file_linters.vader

@@ -1,6 +1,11 @@
 Before:
   Save g:ale_run_synchronously
+  Save g:ale_buffer_info
+  Save g:ale_linters
+
+  let g:ale_buffer_info = {}
   let g:ale_run_synchronously = 1
+  call ale#ResetLintFileMarkers()
 
   let g:buffer_result = [
   \ {
@@ -95,8 +100,6 @@ Given foobar (Some imaginary filetype):
   baz
 
 Execute(Running linters without 'lint_file' should run only buffer linters):
-  call ale#ResetLintFileMarkers()
-  let g:ale_buffer_info = {}
   call ale#Queue(0)
 
   AssertEqual [
@@ -115,9 +118,6 @@ Execute(Running linters without 'lint_file' should run only buffer linters):
   \], GetSimplerLoclist()
 
 Execute(Running linters with 'lint_file' should run all linters):
-  call ale#ResetLintFileMarkers()
-  let g:ale_buffer_info = {}
-
   Assert filereadable(expand('%:p')), 'The file was not readable'
 
   call ale#Queue(0, 'lint_file')
@@ -150,9 +150,6 @@ Execute(Running linters with 'lint_file' should run all linters):
   \], GetSimplerLoclist()
 
 Execute(Linter errors from files should be kept):
-  call ale#ResetLintFileMarkers()
-  let g:ale_buffer_info = {}
-
   Assert filereadable(expand('%:p')), 'The file was not readable'
 
   call ale#Queue(0, 'lint_file')
@@ -189,3 +186,41 @@ Execute(Linter errors from files should be kept):
   \   'type': 'E',
   \ },
   \], GetSimplerLoclist()
+
+Execute(Linter errors from files should be kept when no other linters are run):
+  let g:ale_linters = {'foobar': ['lint_file_linter']}
+  Assert filereadable(expand('%:p')), 'The file was not readable'
+
+  call ale#Queue(0, 'lint_file')
+
+  AssertEqual [
+  \ {
+  \   'lnum': 1,
+  \   'col': 3,
+  \   'text': 'file warning',
+  \   'type': 'W',
+  \ },
+  \ {
+  \   'lnum': 2,
+  \   'col': 3,
+  \   'text': 'file error',
+  \   'type': 'E',
+  \ },
+  \], GetSimplerLoclist()
+
+  call ale#Queue(0)
+
+  AssertEqual [
+  \ {
+  \   'lnum': 1,
+  \   'col': 3,
+  \   'text': 'file warning',
+  \   'type': 'W',
+  \ },
+  \ {
+  \   'lnum': 2,
+  \   'col': 3,
+  \   'text': 'file error',
+  \   'type': 'E',
+  \ },
+  \], GetSimplerLoclist()